This document provides a summary of a swine nutrition guide. It discusses the objectives of the guide in providing practical information on pig nutrition. While the pig's nutritional needs have remained largely the same, knowledge of defining precise nutrient requirements and providing them effectively has grown tremendously. The guide aims to serve as a single reference source on topics like nutrient use, requirements, and effective diet formulation for pork producers, agribusiness workers, and students. It discusses factors like genetics, environment, health, and economics that must be considered in holistic feeding programs.

1. Growel' Swine
Nutrition Guide

2. Preface
The objective ofthe Swine Nutrition Guide
remains the same: to provide the reader with a
simple, easy-to-read source ofpractical information
on the nutrition of the pig. Fundamentally, the pig
has changed little since 1989 when the first edition
was released; ofcourse, genetic progress has been
impressive, but the list of nutrients required by the
pig and how they are used have remained much the
same.
What has changed over the past 6 years is the
tremendous growth in knowledge on how to define
nutrient requirements and how to provide these
nutrients more precisely and effectively with a
keener eye to economics. Perhaps even more
striking has been the rapid progress ofpork produc-
ers in their ability to take advantage ofthis informa-
tion and apply it "on the farm."
The target audience ofthe Swine Nutrition Guide
also remains the same: pork producers, workers in
agribusiness and extension, and students. The
common interest is information on how the pig uses
nutrients, how to determine the nutrient require-
ments of a given class of swine and how feedstuffs
can be most effectively employed in the diet. We
sincerely hope that the Guide continues to fill this
need - serving as a single source reference on these
topics.
The book is not intended to make all readers pig
nutritionists, but rather to provide an understanding
and appreciation for the importance ofa holistic
approach to the subject; the pig does not exist in a
vacuum and to be successful, feeding programs
must be designed with many factors in mind,
including genetics, the environment, herd health
and, ofcourse. economics.
The format of the second edition remains the
same as the first. Chapters l, 2 and 3 provide
background on the more fundamental aspects of
nutrition. Chapter 4 describes more than 40 com-
mon ingredients, including recommendations on
how they might be used in pig diets. Chapter 5 then
explains how to successfully formulate diets,
emphasizing a balanced approach to this sometimes
complex subject but also briefly explaining the
specific mechanics as well.
Chapters 6 to 9 discuss the day-to-day feeding of
various classes ofswine. Because nutrition cannot
be considered in isolation, other aspects of manage-
ment are also included. The authors have taken a
more factorial approach to the design offeeding
programs than in the first edition. This reflects
what we believe to be a growing trend in pig nutri-
tion - to define nutrient requirements on the basis of
specific traits and desired levels ofproductivity,
with economics being considered in all instances.
Chapter 10 considers the processing and manufac-
turing of pig diets, a step that is often taken for
granted - at considerable peril. Mixing and delivery
offeed to the pig represents the final step in the
nutrition continuum. Failure to manufacture diets
properly can erase any gains achieved through
improved diet formulation or ingredient selection!
Chapter 11 provides information on toxins or
antinutritional factors that may be present in feeds
and feedstuffs, either as a consequence of contami-
nation or due to the natural composition ofthe
feedstuff itself. A new chapter (12) on water has
been added to the second edition ofthe Swine
Nutrition Guide, discussing both nutritional and
quality issues.
We trust that the interests of the individual pig are
not lost in the pages ofthis book. Readers will note
that considerations ofpig behaviour creep into
many chapters as we learn more about this aspect of
the animal that we serve - and who has served us so
well. Our respect and affection for this creature, at
once both intelligent and stubborn, fun and frustrat-
ing, neat and messy, motivate us to again dedicate
the Swine Nutrition Guide to the pig.
J.F. Patience
P.A. Thacker
C.F.M. de Lange

3. Table of Contents
1. The Science of Nutrition I
What is Nutrition 1
The Role ofthe Computer . 3
The Future ofNutrition 4
2. Gastrointestinal Physiology 5
The Role of the Digestive Tract .. . 5
Types of Digestive Tracts 6
Eating and Swallowing 7
The Stomach .................................................................................................. 7
The Small Intestine . . . . 9
The Large Intestine ................ ...... . ..... ................................ ........... 12
3. Nutrients 15
What is a Nutrient ................................................... .... ...................... 15
Nutrient Availability 15
Nutrient Requirements .. . . . . 16
Energy 16
Amino Acids ........................ .. ........ .................... ................... 22
Minerals 31
Vitamins .... .. . 40
Essential Fatty Acids . . . ................................................ . ........... 48
Water 49
4. Ingredients 51
Ingredient versus Nutrient .. 51
Animal Sources 53
Blood Meal ....... ..... ................. .................................................. 54
Bone Meal 55
Feather Meal 55
Fish Meal .. .. 56
Fish Silage 57
Meat and Bone Meal .... 59
Whole Milk 60
Dried Skim Milk 61
Whey 61
Plant Sources .. . . . . . .. 63
Alfalfa 63
Barley 65
Barley: High Moisture 67
Barley: Hulless 69
Beet Pulp 71
Buckwheat 71
Canola Meal . . . .... 73

4. Canola Seed: Full Fat 74
76
78
80
80
82
84
Grain Screenings 84
Lentils 86
Molasses 87
Oats 87
Oats: Naked .... . . . 89
Oat Groats .. . . . 90
Potatoes and Potato Products ......... ........................... ...................... 90
Rye 92
Soybeans: Full Fat . . .. 93
Soybean Meal 96
Sunflower Meal . . . 97
Sunflower Seeds .... . . 98
Triticale ...... . . . . . 100
Wheat 101
Wheat Bran .......................................... ..................... ..................... 104
Wheat Shorts . . . 105
Wild Oat Groats . . . . . . 105
Fats and Oils . . . . . .. 107
Mineral Ingredients .. .. 112
Probiotics 113
Synthetic Amino Acids 115
Organic Acids 115
Feed Flavours ..................................... ................. ............................... 116
5. Diet Formulation 119
Define Objectives .... . 119
Define Requirements 121
Select and Characterize Ingredients 122
Diet Formulation 123
Evaluating Diet Quality 128
Conducting a Feeding Trial 131
Common Calculations and Conversions 132
6. Nutrition of the Breeding Herd 133
Feeding and Management of Replacement Gilts 134
Feeding the Sow During Gestation 137
Feeding the Sow Around Farrowing Time 151
Feeding the Sow During Lactation 154
Feeding the Sow at Weaning 161
Feeding Boars 162
Grain Dust .
Corn .
Corn By-Products .
Dried Bakery Product .
Fababeans .
Field Peas ..

5. 7. Feeding the Suckling Piglet 167
The Importance ofColostrum . .. 167
The Need for Supplementary Iron 168
Water Requirements 168
Use of Milk Replacers I 69
Creep Feeding . . .... . . . . . . . . . 169
8. Feeding the Weaned Pig 173
Stresses at Weaning 173
Performance Targets 174
Maximizing Feed Intake I 74
Managing the Early-Weaned Pig 176
Nutrient Requirements ofthe Weaned Pig 177
Feeding Programs .. . . 178
Diet Composition . . . . .. 180
Diet Formulations . . . 183
Feed Additives ..... . . . . 183
The Pig's Environment 184
9. Feeding Management of Market Hogs 187
Goals for the Feeder Barn . 187
Lean Tissue Growth in Growing-Finishing Pigs 188
Feed Intake in Feeder Pigs ....................................... ............................ J 91
Feed Utilization in Feeder Pigs . . 192
Factors Affecting Nutrient Requirements in Growing-Finishing Pigs l 94
Nutrient Allowances and Diet Formulation . 196
Typical Diets ..................................................................................... ... 20 l
Feed Additives ..... . . 203
Phase Feeding 203
Split-sex Feeding 204
Feeding to Appetite Versus Restricted Feeding .. 206
Choice Feeding .. . .. . .. 207
Feeding of Pigs Housed Outdoors . . 207
Feed Separation . . . 208
Feed Wastage .. . 209
Monitoring Performance . .... 210
Meat Quality 213
10. Diet Processing and Delivery 215
Grinding . .... . . .... . 216
Mixing 219
Pelleting . .. . . . . . . . . . 220
Liquid Feeding 223
Drying Grains 224
High Moisture Grains 224
Mixing Feeds on the Farm 225
Processing Problems 226
Feeds Act and Regulation 227

6. 11. Toxic Substances in Feeds 231
Toxicants Produced by Plants 231
Exogenous Microbes and Toxin Producers 235
Prevention ofMycotoxin Contamination 239
Treatment 239
Safety 240
12. Water 241
Requirements and Intake ... . 241
Gestating Sows . . . .. 242
Lactating Sows 243
Piglets .. . .... . .. 243
Weanling Pigs . 244
Water Delivery .. 244
Water Quality 245
Impact ofWater Quality . 248
Response to Poor Quality Water 249
Appendix I. Typical Nutrient Composition of Selected Feed Ingredients 253
Appendix II. Calibrating Proportioner-Type Mills 261
Conversion Factors ........ ........................................................................... 262
Glossary ......... ...... ............ ....................... . ........................................ 265
Index 271

7. List of Tables
3-1. Essential Nutrients in the Diet of the Pig 15
3-2. Proportions of Gross, Digestible and Metabolizable
Energy (Kcal/kg) in Common Ingredients 18
3-3. Fibre Content of Ingredients Used in Swine Diets 19
3-4. Digestibility of Ether Extract of Common Feedstuffs 20
3-5. Effect of Bushel Weight on Nutrient Content of Cereal Grains 21
3-6. Minimum Recommended Bushel Weightsfor Grains Used in
Swine Rations 21
3-7. Nitrogen Content of Amino Acids 24
3-8. Protein Estimation Adjusted for Corrected Nitrogen Factors
and Non-Protein Nitrogen Content 24
3-9. Amino Acid Profile ofVarious Protein Fractions in Com 26
3-10. Effect of Increasing Total Nitrogen (Crude Protein) on the Lysine
Content of Wheat and Oats 26
3-11. Average Apparent Availability ofAmino Acids(%) in
Common Ingredients 28
3-12. Suggested Optimum Amino Acid Balance in Protein
(Ideal Protein) for Swine 31
3-13. Approximate Mineral Composition of the Animal Body 32
3-14. Total Phosphorus Content and Phosphorus Availability
of Some Common Ingredients 33
3-15. Feed Grade Phosphate Sources 33
3-16. Calculating 'Salt' Values from Sodium or Chloride Assays in Swine Diets 35
3-17. Maximum Tolerable Limits and Supplemental Sources
of the Microminerals 37
3-18. Stability ofVitamins in Premixes and During Pelleting and Extrusion 43
3-19. Alpha-tocopherol Content of Feed Ingredients 45
4-1. Consistency ofVarious Protein Sources used in Swine Diets 52
4-2. Performance of Weanling Pigs Fed Diets Containing Graded
Levels offish Silage 58
4-3. Performance of Growing Pigs (25 to 55 kg body weight) Fed Diets
Containing Graded Levels of Oily Fish Silage (44% fat in the pure product) 58
4-4. Effect of Feeding Fish Silage on the Reproductive Performance of Sows 58
4-5. Replacement Scheme for Using Whole Milk in Swine Diets 61
4-6. Growth, Feed Intake and Carcass Characteristics of Pigs
(54-100 kg) Fed Alfalfa 64
4-7. Composition ofBarley Varieties and Performance of
Growing-finishing Pigs (approximately 20-95 kg body weight)
Fed Various Barley Varieties 65
4-8. Utilization of Frozen or Sprouted Barley (Bonanza) by Growing Pigs 67
4-9. Chemical Analysis of High Moisture and Dry Barley 68
4-10. Amount of High Moisture Grain Necessary to Supply the Same
Amount of Dry Matter as Regular Barley (90% DM) 69
4-11. Performance and Carcass Characteristics of Pigs Fed Acid-treated
High Moisture Barley (74.5% CM) or Regular Barley (85.8% DM) 69
4-12. Performance of Starter Pigs Fed Condor Hulless or Samson Hulled Barley 70
4-13. Performance of Growing-finishing Pigs Fed Diets Based on Hulled or
Hulless Barley 70
4-14. Performance of Growing Pigs (20-60 kg) Fed Diets Containing
Various Levels of Buckwheat in Combination With Barley 72

8. 4-15.
4-16.
4-17.
4-l8.
4-19.
4-20.
4-21.
4-22.
4-23.
4-24.
Performance of Female and Castrated Male Pigs Fed Diets
Containing Equal Levels of Digestible Nutrients
Performance of Starter Pigs Fed Diets Containing Whole Canola Seed
Performance and Carcass Composition of Pigs Fed Diets Containing
Whole Canola Seed
Nutritional Value of Immature Com
for Starter Pigs Fed Corn-Soybean Meal Based Diets
Effect of Bushel Weight on Rate and Efficiency
of Growth and on Digestibility of Energy in Corn
Performance of Starter Pigs ( l 0-25 kg) Fed Graded Levels of Fababeans
Performance of Grower Pigs ( 16-45 kg) Fed Diets Containing Fababeans
Effect of Fababeans on Reproductive Performance
Performance of Pigs (27-95 kg) Fed Peas as a Replacement for Soybean Meal
Performance of Growing-finishing Pigs (25-90 kg) Fed a
Mixture of Peas and Canola Meal
73
75
75
77
79
81
81
81
83
83
4-25.
4-26.
4-27.
4-28a.
4-28b.
4-29.
4-30.
4-31.
4-32.
4-33.
4-34.
4-35.
4-36.
4-37.
4-38.
4-39.
4-40.
4-4 l.
4-42.
4-43.
4-44.
4-45.
4-46.
4-47.
4-48.
4-49.
4-50.
Comparison of the Composition of Grain Dust and Parent Grains 84
Chemical Composition of Five Samples of
Feed Wheat Screenings Compared to Wheat 85
Effects of Feeding Cull Lentils on Digestibility and Pig Performance (23-100 kg) 86
Effect of Substituting Oats for Com on the Performance of Weaner Pigs 88
Effect of Substituting Oats for Com on Grower Pig Performance 88
Comparison of Naked Oats and Other Cereal
Grains as an Energy Source for Weaner Pigs (25-56 days). 89
Performance of Market Hogs Fed Naked Oats (32-79 kg) 89
Effect of Enzyme Supplementation on the Performance of
Growing Pigs (20-98 kg) Fed Rye 93
The Effect of Heat Treatment on the Digestible Energy Content of Soybeans 95
Performance of Growing-finishing Pigs Fed Roasted Beans as the
Sole Supplemental Protein Source in Com-based Diets 96
Effect of Feeding Sunflower Seeds on the Performance of Weaner Pigs 99
Performance of Growing Pigs Fed Graded Levels of Sunflower Seeds 99
Trypsin Inhibition Levels in Spring Triticale I 00
Performance of Grower Pigs Fed Diets Containing Triticale, Wheat or Com l OI
Comparison of Hard and Soft Wheat in the Diet of Pigs from 61 - L2 l kg 102
Replacement of Hard Red Spring Wheat
with Soft Wheat in Pig Starter Diets l 02
Performance of Starter Pigs Fed Either Sprouted or Regular Soft Wheat I 04
Typical Specifications for Wheat and its By-products I 05
Performance of Starter Pigs (7-25 kg) Fed Various Oat Products 106
Estimating Iodine Value from Fatty Acid Composition of a Fat l 09
Digestible Energy Content of Selected Fat Sources 11 O
Summary of Responses to Supplemental Fat in Sow Diets 11 I
Fat Content - Common Feed Ingredients I I I
Typical Analysis(%) of Common Mineral
Ingredients Used in Swine Diets 112
a. Macrominerals 112
b, Microminerals 113
Performance of Starter Pigs Fed Diets Containing a Probiotic 114
Performance of Growing Pigs (23-38 kg) Fed Diets Containing a Probiotic 114
Effect of Organic Acid Supplementation on Starter Pig Performance 116
5-1.
5-2.
5-3.
Typical Ingredient Output from a Feed Formulation Program
Typical Nutrient Output from a Feed Formulation Program
Diet Composition from Pierson Square Calculation
124
125
127

9. 5-4. Recommended Schedule for Feed Testing on a Farm Manufacturing Three Diets 129
5-5. Calculation of the Theoretical Nutrient Composition of a Feed 130
5-6. Examples of Conclusive and Inconclusive Test Results Based on ADG 132
6-1. Reproductive Efficiency ofAverage and Superior Swine Herds 133
6-2. Influence ofFeeding Level Following Mating on Embryo Survival in Gilts 136
6-3. Effect ofFeed Level in Early Gestation
on Plasma Progesterone Levels and Embryo Survival 136
6-4. Effect of Energy Intake (day 75 to I 05 of Gestation) on Mammary
Development in Gilts 137
6-5. Comparison of Sows Fed with Electronic Sow Feeders or in Gestation Stalls 139
6-6. The Influence of Dispensing Speed on the Behaviour and Feed Intake of
Sows Using the Slow Feeding System 141
6-7. Effect of Feeding Level During Last 23 days of Gestation on
Reproductive Performance 144
6-8. Components of Gestational Weight Gain 144
6-9. Feed Allowances for Dry Sows According to Body Condition Score 145
6-10. Metabolic Body Weights of Sows and Maintenance Energy Requirements 145
6-1 I. Energy Requirements of Sows (estimated) During Gestation 147
6-12. Daily Amino Acid Requirements for Maintenance of Gestating Sows 148
6-13. Daily Amino Acid Requirements {g/day) for Growth of Gestating Sows 148
6-14. Estimated Total Amino Acid Needs of Pregnant Sows Under
Various Conditions 149
6-15. Mineral Requirements of Gestating Sows 150
6-16. Vitamin Requirements of Gestating Sows 150
6-17. Effects of Folic Acid Supplementation of Diets Fed to Gestating Sows 150
6-18. Effect of injection of Beta-Carotene on Reproductive Performance of
Multiparous Sows 151
6-19. Effect ofVitamin E on Sow Productivity 151
6-20a. Examples of Gestation Diets 153
6-20b. Examples of Lactation Diets 153
6-21. Effect ofType of Fat Fed During Late
Gestation and Early Lactation on Sow Productivity 154
6-22a. Effect of Sow Feed Intake During Lactation
on Subsequent Reproductive Performance 154
6-22b. Effect of Feed Level on Milk Yield at 21 Days 155
6-23. Effect of Feed Intake During Pregnancy on Feed Intake During Lactation 155
6-24. Effect of Feeding Various Levels of Protein During Lactation
on Sow Feed Intake and Body Condition 156
6-25. Effect of Method of Feeding on Sow Feed
Intake and Weight Change During Lactation 156
6-26. Performance of Sows Fed Artificial Flavours During Lactation 157
6-27. Effect of Environmental Temperature on Feed Intake and Weight
Loss of the Sow and Weight Gain of the Litter 158
6-28. Estimated Daily Energy Requirements of Lactating Sows 159
6-29. Estimated Daily Amino Acid Requirements for Milk Production by the Sow 160
6-30. Estimated Total Daily Amino Acid Requirements of Lactating Sows 161
6-31. Effect of Feed and Water Deprivation.
Prior to Weaning, on Days to Successful Service After Weaning 161
6-32. Effect of Feed Intake During the Weaning to Remaining Interval
on the Reproductive Performance of Gilts and Sows 162
6-33. Nutrient Requirements of Developing Boars (20-100 kg) 163
6-34. Energy Requirements of Working Boars 164
6-35. Composition of Diets for Adult Boars 165

10. 7-1 Effect ofWeaning Weight at 25-29 Days
ofAge on Piglet Performance to 78 Days ofAge 167
8-1. Recommended Weaning Age for Disease Elimination 174
8-2. Performance Targets for Pigs from 7 to 25 kg Body Weight 174
8-3. Nutrient Requirements of the Weanling Pig 176
8-4. Diet Composition Guidelines for the Weanling Pig 181
8-5. Sample Diets for Weanling Pigs 182
8-6. Effect of Medication on the Performance of Weanling Pigs in a High Health Herd 183
8-7. Recommended Floor Space Allowances for Weanling Pigs 185
9-1. Goals for the Feeder Barn 187
9-2. Saskatchewan Grading Table 190
9-3. Observed Lean Growth Rates in Growing-finishing Pigs in
Relation to Growth Rates and Carcass Lean Yield Content 191
9-4. Effect of Health Status on Performance in Growing-finishing Pigs 195
9-5. Estimated Available (apparent ilea! digestible) Lysine Requirements
for a Growing Pig at 50 kg Body Weight 196
9-6. Estimation of the Lowest Cost per Unit of Energy in Growing Pig Diets 197
9-7. Effect of Dietary Energy Density on the Voluntary Feed Intake
and Performance of Entire Male Pigs between 22 and 50 kg Body Weight 197
9-8. Recommended Allowances ofAvailable(apparent ilea) digestible)
Lysine in Relation to Lean Growth Potential and Body Weight
in Growing-finishing pigs 198
9-9. Estimated Change in the Balance in which Amino Acids are
Required by Growing Pigs with Average Lean Growth
Potentials and with Increasing Body Weights 199
9-10. Recommendations for Vitamin Fortification of Grower and
Finisher Diets 199
9-11. Recommendations for Mineral Levels in Grower and finisher Diets 200
9-12. Examples of Growout Diets based on Wheat and Barley 201
9-13. Examples ofGrowout Diets Based on Corn 202
9-14. Pig Response to Antimicrobials in Feed of Growing-finishing Pigs 203
9-15. Estimated Value of a One versus Two versus Three Phase Feeding
Program in Pigs with Average Lean Growth Potential 204
9-16. Performance of Barrows and Gilts Fed a Similar Diet 204
9-17. Effect of Sex and Dietary Lysine Level on Performance in Finishing Pigs 205
9-18. Estimated Effect of Level ofFeed Intake on Animal and Financial
Performance in Pigs with a Slightly Better than Average
Lean Growth Potential 207
9-19. Performance Data Comparing Shelter and Conventionally Raised
Feeder Pigs During the Summer, Fall and Winter 208
9-20. Effect of Feed Handling on Pig Performance 209
9-21. Effect of Floor feeding on Growing-finishing Pig Performance 209
9-22. Effect of Feed Form on Performance of ad libitum Fed Pigs 210
9-23. Calculation of Days to Market Based on Inventory Turnover 211
9-24. Estimated Performance of Feeder Pigs Based on Feed Intake and
Growth Curves Presented in Figure 9-11 213
9-25. Recommended Pen Floor Space Allowances for Growing Pigs 214
10-1. Effect of Fineness of Grind on the Performance ofWeanling Pigs
Fed Barley-based Diets 216
10-2. Effect of Fineness of Grind on the Performance of Finishing
Pigs Fed Barley-based Diets 216

11. 10-3. Effect of Particle Size on the Performance of Lactating Sows
Fed a Corn-based Diet 217
10-4. Impact of Fineness of Grind on Mill Productivity and Energy Efficiency 217
10-5. Effect of Screen and Hammer Wear on Grinding Effectiveness 218
10-6. Effect of Fineness of Grind of Corn on Incidence of Ulcers
and other Stomach Lesions in Swine 219
10-7. Effect of Fineness of Grind of Barley on the Incidence of Ulcers
and other Stomach Lesions in Swine 219
10-8. Impact of Mixing Time on Diet Uniformity and Performance of
Weanling Pigs 219
10-9. Impact of Mixing Time on Diet Uniformity and Performance of
Finishing Swine 220
10-10. Impact of Pelleting Corn-based Diets on Finishing Pig Performance.
Nutrient Digestibility and the Incidence of Ulcers 221
10-11. Effect of Pelleting Diets based on Canola and Cereal Grains on
Pig Performance 222
10-12. Effect of Pellet Fines on Performance of Finishing Pigs Fed a
Corn-based Diet 222
10-13. Effect of Pelleting and Fines on Performance of Newly-weaned
Pigs Fed Com-based Diets 223
10-14. Separation of Feeds Following Mixing on the Farm 226
10-15. Nutrient Guarantees Required for Swine Diets that are Exempt
from Registration Requirements 228
11-1. Phytate Phosphorus Content of Common Feedstuffs 232
11-2. Naturally-occurring Phytase in Common Feedstuffs 232
11-3. Results of Salmonella Assays Reported by the Veterinary
Diagnostic Laboratory at the Pennsylvania State University 235
11-4. Survey of Raw Materials Provided by Five Feed
Compounders in the U.K. 235
12-1. Nipple Drinker Flow Rates on Saskatchewan Farms 244
12-2. Recommended Nipple Drinker Flow Rates for Various Classes of Swine 245
12-3. Canadian Water Quality Guidelines for Livestock 245
12-4. Assays to Include in the Chemical Evaluation
of Water Used in Pig Production 246
12-5. Effect ofAeration and Seven Days Settling on Water Chemistry 247
12-6. Effect of Water Quality on the Performance
of Weanling Pigs Fed a Diet Containing Antibiotics 248
12-7. Effect of Water Quality on the Performance of
Weanling Pigs Fed a Diet Free ofAntibiotics 249
12-8. Effect of Pen Temperature and Water Quality on the
Performance of Newly-weaned Pigs 249

12. List of Figures
I-la. Cost of Production Budget: all costs
I-lb. Cost of Production Budget: variable costs only
2-1. Gastrointestinal Tracts 6
2-2a. Capacity of Gastrointestinal Tract 7
2-2b. Length of the Gastrointestinal Tract 7
2-3. Nutrient Digestion along the Gastrointestinal Tract of the Pig 12
3-1. Pig Response to Level of Nutrient in the Diet 16
3-2. Distribution of Dietary Energy 17
3-3. Relationship of Protein Content to Protein Type in Cereal Grains 26
3-4. Relationship between Amino Acid Level in Diet and Observed
Apparent and Calculated "True" Ilea! Amino Acid Digestibilities
(Figure 3-4a.), and the Relationship between Amino Acid Level in Diet
and Observed Recovery at Distal £1eum (total endogenous and
non-digested dietary aminoacids) (Figure 3-4b.) 29
3-5. Diagram Tllustrating What is Meant by the Term Amino Acid Balance
as it Relates to Evaluating Swine Diets 30
4-1. Flow Diagram Showing Choices in Selection
of Ingredients used in Practical Diets 53
4-2. Triglyceride 107
5-1. Determination of a Nutrient Requirement Showing the Pig Response to
increasing Nutrient Supply 122
5-2. Quality Control Procedures on the Farm 130
6-1. Effects of Feed Intake During Pregnancy on Sow Productivity 138
6-2. Diagram of Slow Feeding System for Sows 140
6-3. Diagram ofWoldrix Feeding System for Sows 141
6-4. Diagram of Hurnick-Morris System for Gestating Sows 142
6-5. Guides to Condition Scoring Sows, Including Photographs of
Representative Animals 146
6-6. Example of a Card for Monitoring Lactation Feed Intake 159
7-1. A Lactation Curve for a Sow 169
7-2. Digestive Enzyme Activity Pattern in Young Swine 170
8-1. Average Daily Gain versus Days to Market 173
8-2. Growth Curves for Pigs Demonstrating Good, Better and Best
Performance to IO Weeks ofAge 175
8-3a. Starter Feed Usage: Two Week Weaning 178
8-3b. Starter Feed Usage: Three Week Weaning 178
8-4. Relationship Between Dietary Energy Concentration and Body Protein
Gain in Weanling Pigs 178
9-1. Sigmoidal Growth Curve 188
9-2. Relative Proportions of Muscle Bone and Fat at Birth and 28 Weeks ofAge 188
9-3. Description of PI, P2, and P3 Fat Measurements 189

13. 9-4. Typical Feed Intake Curve for Growing Pigs Consuming a Diet
with a DE Content of Either 3150 or 3400 kcal/kg. 192
9-5. Relationship between Feed lntake and Tissue Accretion Rates in Growing Pigs 193
9-6. Effect of Feed Intake on Lean Tissue Growth and Body Fat
Deposition in Finishing Pigs with Average ("average pig")
and High ("good" pig) Lean Tissue Growth Potential 193
9-7. Relationship between Feed Intake and
Performance in Growing Pigs where Energy Lntake Limits Lean
Growth (Figure a), and in Finishing Pigs Where Feed Intake
does not Limit Lean Growth (Figure b) 194
9-8. Effect of Dietary Lysine Levels and Pig Type on Lean Growth Rates 194
9-9. Change in Required Dietary Nutrient Levels in Relation to Body Weight 195
9-10. Feed Intake Curves of Barrows and Gilts Fed a Similar Diet and
Housed in Groups of 12 Pigs per Pen 205
9-l 1. Estimated Feed lntake and Growth Curves
Derived from a Limited Number ofDetailed Observations on
Feed Lntake and Body Weights in a Feeder Barn 212
10-1. Improvement due to Grinding on the Digestibility ofNutrients for
Two Sizes of Pigs 216
12-1. Water Balance in the Pig: Intake and Output 241
12-2. Typical Water Intake Pattern During the Post-weaning Period 244

15. DIET INGREDIENTS
BLOOD MEAL BONE MEAL
•• •
•
•
. •..., .
• •
FEATHER MEAL FISH MEAL FISH SILAGE (CAPELIN)
SKIM MILK POWDER WHEY POWDER ALFALFA: DEHYDRATED
MEAL
BARLEY BARLEY:HULLESS

16. BEET PULP
;-:_, '') 'I • I
. ' .. , ..· .. ,' _...,, . -c..·1;. •. . . , .. ,.' '!-' ','.,.� ,,, ·. --.••
. It ... •• > .,..• . ' .. ,li"J, .
• ; ,: ·�.� �.-•. • '{ y'·� '�I :.,': ....
.�----J' •;- .. , i;.'1_
•.Jo_�:·"" .:.,�.�... .: ; +-&-,. �
.• . ... , . ':j'' . ·, • i � 'l_ "i!'
' • I I • , { ! ll"". :• > � . ;' ....
1·· s I . . .:--..:.· .,. "I ; -.,I,, .• • .; I '(. e • •
... . -. .,..· .�· :· ..-'( �...�·· ,
... ' ' ' , . ' . '• . -·,, ... ' A' • ,. • � I• �� .,, • • I ��
• I• 4 «r: �. • :'� '. / I ..,/
• . •.-� ' .•.,«•..... ,' . , .'· ... �-' - ;I a---;' _- .... ,;· ,· • • • .
. t t -. .. ", �� ...
CANOLA: FINE
SCREENINGS
CORN: DISTILLER'S
GRAIN
DRIED BAKERY PRODUCT
CANOLASEED
CORN
CORN: MOLDY
ERGOT
CANOLA MEAL
CORN:CRACKED
FABABEANS

17. FIELD PEAS (PRINCESS)
MOLASSES
DEHYDRATED
SOYBEAN SEED
FIELD PEAS (TIPU)
OATS
RYE
SOYBEAN MEAL
LENTILS (LAIRD)
OATS: NAKED (TARA)
RYE: WITH ERGOT
SUNFLOWER SEEDS

18. SUNFLOWER MEAL:
DEHULLED
WHEAT BRAN
L-THREONINE
TRITICALE
MHA LIQUID
L-TRYPTOPHAN
WHEAT
CANOLA OIL: CRUDE,
DEGUMMED
DL-METHIONINE
l
LYSINE HCI

19. 1. THE SCIENCE OF NUTRITION
Despite major changes in the nature ofthe swine
industry in Canada, the cost offeed remains the
largest single expense involved in raising pigs.
Although the exact cost varies greatly depending on
grain and protein markets, the total feed bill for the
Canadian pork industry approaches one billion
dollars. Even modest savings would provide
benefits to the swine industry in the millions of
dollars.
At the farm level, feed represents slightly more
than 50% ofthe total cost ofproduction and about
75% of the variable costs (Figure 1-1). It surpasses
the next largest expense - fixed costs associated
with housing- by a factor ofthree. Simple logic
dictates that optimizing feed costs - selecting
feeding programs that maximize net income - is a
critical step in ensuring success in pork production.
Figure 1-la. Cost of production budget: all costs.
..
•II FEED 11
111111111 72% 11111111
11111
111111111111111111111111111111111111111111111111111111111
111111
Figure 1-1 b. Cost of production budget: variable
costs only.
It is our experience that much can be
accomplished to reduce feed costs and increase net
income. Linking nutrient supply to nutrient
requirements represents a reasonable, if not
essential goal, but it becomes difficult at the farm
level due to differences in genetics, housing, health
status and overall production objectives.
Recently, a sampling offarrow-to-finish
operations on the Canadian prairies suggested that
feed costs, expressed on a per pig sold basis, varied
by almost 100%! While the lowest feed cost may
not be associated with the highest profitability, it is
clear that such variability is inexplicable by normal
economic and biological principles. The obvious,
and correct conclusion is that nutrients are being
wasted; the source ofsuch waste varies from poor
feed presentation through to diet over- formulation.
Clearly, opportunities exist for significant cost
savings through the application ofincreased knowl-
edge in nutrition. The nutritionist must be able to
identify such opportunities and exploit them effec-
tively. The purpose ofthis book is to provide
practical information on the subject ofnutrition to
afford nutritionists, pork producers and their associ-
ates the capability to exercise greater control over
their feeding programs.
What is Nutrition?
What exactly is nutrition? It is the science that
studies the nutrients needed by animals: how much
ofeach is required in a healthy diet, how they can
be supplied in an economical fashion andhow the
body utilizes them for maintenance, growth and
production. Nutritionists are concerned with
improving the chemical analysis offeeds and
feedstuffs to better reflect their true value to the
animal. Information is drawn from other fields of
science, such as biochemistry and physiology, to
help us understand the basic processes in the body
that dictate the ultimate fate ofthe feed that animals
eat. The essence ofnutrition is to define the
nutrients required by the animal to perform at a

20. desired level, identify a suitable source ofthese
nutrients and match the two (requirement and
source) in a diet formulation.
This is not a simple task. Nutrient requirements
fluctuate according to many environmental, genetic
and physiological influences. For example, grow-
ing pigs with a maximum protein deposition rate
(Pdma.> of 170 grams per day will have a very
different requirement for essential amino acids than
those with a Pd of 150 grams per day. Sowsma.,
housed outdoors require more nutrients, and thus
more feed, than sows housed indoors. This is
particularly true during the winter.
Diets, therefore, cannot be formulated in a
vacuum; the total circumstances surrounding the
animal including its environment and the type of
farming operation involved must be considered. In
the same way that an engineer designs a barn with a
view towards the producer's management style and
his overall production objectives, the nutritionist
must formulate diets that will complement other
aspects ofthe farm. No single diet will suit all
farming operations.
Diets can not be formulated in a vacuum. Like designing
a barn, feed formulation must consider the total manage-
ment situation including genetics, housing, health, and of
course. economics.
The nutrients supplied by a given ingredient are
sometimes difficult to determine with precision, due
partly to the limitations ofthe chemical analyses
currently available and in part to the many factors
that influence how available these nutrients might be
to the animal.
t<>t> o 0
NUTRIENTS
I t» <>
0 I> 0
QUANTITY
EATEN
PER DAY
"-.. <> g<>o
i t» <> 0
MIXED DIET INGREDIENT A INGREDIENT B
Pig nutrition embraces three components: nutrient requirements, nutrient sources, and daily feed intake.
2

21. It is also a challenge to determine the intake of
diets, since feed intake will obviously dictate
nutrient intake. The physical capacity ofthe gas-
trointestinal tract plays a role, particularly in nurs-
ing sows, weanling pigs and growing pigs. The
importance of feed intake in practical nutrition is
becoming increasingly apparent, in part because of
the considerable variation that exists among farms -
in the order of30% in the grow out period, for
example. Measuring true feed intake is being
viewed as increasingly important, although it tends
to be a time consuming process.
Palatability is another factor. However, people
will often make the mistake ofascribing human
tastes to the pig. Yet, the pig will eat many things
that humans will not, while some components ofthe
human diet are met with disdain by the pig! Great
care should be taken to avoid altering the diet to
improve what we might think is its palatability. The
pig may have very different opinions on the subject,
and the producer may end up with a more expen-
sive, but no more desirable diet.
The Role of the Computer
In the past 15 years. the computer has become an
indispensable tool to the professional nutritionist for
formulating diets. Farmers who choose to manufac-
ture their own diets now have the added option of
using feed formulation programs designed for the
home computer. Time will tell ifpork producers
choose this option, or decide to leave diet formula-
tion to professional nutritionists working for the
feed industry, provincial extension services or
private consultants.
The use ofthe computer in formulating diets has
met with considerable skepticism, focusing on the
mechanical and unfeeling way with which it com-
bines feedstuffs into a diet. This ignores the incred-
ible power the computer brings to the whole area of
diet formulation. Certainly, the computer is only as
good as the nutritionist operating it and mistakes
can be made. However. the chances oferror are far
more likely with manual calculation. For all their
faults, computers are notably less prone to mistakes
than their human masters! Dependency on the
3
computer has led to errors in diet formulation, but
invariably these can be traced to human mistakes in
programming.
Photo 1 - 1.
The computer can be an enormously useful tool to help
monitor the performance of the breeding herd. It is not a
replacement for good management; itjust makes it easier
and more effective.
The computer has allowed the nutritionist to
move ahead with much greater speed. A balanced
diet contains 40 or more known nutrients. Using
manual calculation methods, it would be impractical
to consider more than three or four nutrients at a
time. With computers. all nutrients can be moni-
tored simultaneously and least-costing programs
focus on a dozen or more ofthe most critical
nutrients. The computer also demands much more
of its nutritionist master in terms ofprecise infor-
mation on nutrient composition, availability, re-
quirements and cost. Researchers have responded
by developing knowledge to accommodate this
expanded need. Finally, computers are being used
increasingly in the development and application of
growth simulation models, with the result that
specific feeding and management programs can be
generated for individual farms. Clearly, in every
respect, the livestock farmer has been a beneficiary
ofthese developments.

22. The Future of Nutrition
What does the future hold for the science of
nutrition? Already, the advent ofbiotechnology is
having an effect. Reduced costs ofsynthetic amino
acids means that we will have more options for
balancing diets, and that our dependency on con-
ventional protein sources such as soybean meal and
canola meal will diminish.
Both improved crops and superior genetic quality
of pigs will alter the way in which we formulate
diets. The most exciting development, however,
will be a vastly improved ability to understand how
the pig grows and uses nutrients. This knowledge
will be oftremendous benefit because it will expand
our ability to match the pig's diet with its needs for
growth and production. It will allow us to
formulate diets for very specific conditions, such as
the growth of lean as opposed to fat in the carcass;
and to integrate environment, disease and genetics
into the final ration. The costly waste ofexcess
nutrients will be eliminated and pork production
will become a much more efficient process.
The rise of the environment as a key issue in pork
production, and the role ofthe diet in determining
the nutrient content ofslurry, dictates that nutrition
and the environment will be intimately linked in the
future. Indeed, diet formulation with a view to
minimizing nutrient waste not only benefits the
environment, but it often leads to reduced produc-
tion costs. It has forced us all to question bow we
balance diets and design feeding programs, particu-
larly with respect to amino acid (nitrogen) and
phosphorus supply.
CROP
The pig plays an integral part in the environment.
4

23. 2. GASTROINTESTINAL PHYSIOLOGY
The science ofnutrition is closely linked to other
scientific disciplines, one ofthe most important
being physiology. Gastrointestinal physiology is
the study ofthe stomach, the small and large intes-
tines and related tissues. It is a subject that helps us
better understand nutrition.
The Role of the Digestive Tract
Before feed can be used by the pig, it must first
be absorbed from the digestive tract into the body.
From a physiological point of view, the material
contained in the digestive tract is considered to be
outside the body. There are very good reasons for
this. Some parts ofthe undigested food are actually
toxic to the body; the intestinal wall acts as a barrier
to prevent, or at least attempt to prevent, the entry
ofunwanted compounds. For example, some intact
proteins can cause an allergic reaction in the animal.
The proteins in the diet are therefore broken down
into their constituent parts called amino acids,
before being allowed to enter the body.
The breakdown of food into simpler and smaller
compounds is called digestion. Digestion not only
converts proteins into amino acids, but it also
breaks carbohydrates down into sugars such as
glucose or fructose. Fats in the diet are converted
into their constituent parts, largely free fatty acids,
monoglycerides and related compounds. Minerals
are also separated into individual elements. Salt is
an example. Salt is chemically known as sodium
chloride and is broken down into its individual
molecules of sodium and chloride. Although not
digested, some vitamins must be modified in the
gut to facilitate their transfer across the gut wall.
All ofthese processes are required in order to
prepare the nutrients for absorption. The enzymes
involved in the digestion offeed are represented
below. The dual processes ofdigestion and ab-
sorption are discussed in more detail later in this
chapter.
e,oSE
Q
Feed ingredients must be broken down in the gastrointestinal tract into individual nutrients such as protein into amino
acids or starch into glucose.
5

24. Types of Digestive Tracts
There is an old saying that "You are what you
eat!" In actual fact, all animals must cat according
to what "they are". Each member of the animal
kingdom has a digestive tract that determines the
type of diet best suited to the animal and dictates
how it should be fed. For example, cattle and other
ruminant animals have a complex stomach which
includes four distinct segments each of which has a
specific function. The rumen is the largest of these
and functions as a large fermentation vat containing
both bacteria and protozoa. The action of these
microbes serves to degrade many feed components
and convert them into more simple compounds.
This fermentation process allows the cow to take
advantage ofthe "bugs" that can break down fibre
or roughage into products that, upon entering the
intestinal tract, can be digested and absorbed.
Pigs differ from cattle in that they possess only a
simple stomach. The pig must depend on its own
digestive abilities because it cannot depend on
microbes in a rumen to do thejob for it. The pig is
able to compensate for this, to some extent, because
"bugs" do live in its large intestine and help to
digest fibre after it leaves the small intestine.
Bacterial digestion is believed to provide a signifi-
cant amount ofenergy to the pig, somewhere in the
range of20 percent of its maintenance energy
requirement.
Stomach Small lnttttlne
Figure 2-1. Gastrointestinal Tracts.
6
As a result ofthe differences in the digestive
tracts ofcattle and pigs, their diets are also differ-
ent. The ruminant digestive tract lends itselfto the
use of feeds with a high fibre content while that of
the pig utilizes more easily digested. low-fibre feeds
such as grains.
All animals with a simple stomach are not alike
in terms of nutrition. Chickens and pigs both have
simple stomachs but differ in many areas.
Small lnlesllne
When one considers all ofthese differences, it is
easy to understand why the digestibility of lower
quality feedstuffs such as barley or oats, is higher in
swine than in poultry, while the digestibility of
higher quality or more easily digested feed ingredi-
ents such as corn or fish meal, is higher in poultry.
The reason appearers to be that the combination of
rate ofpassage and mixing, which occurs in the
intestinal tract ofthe chicken, maximizes the use of
highly digestible ingredients, but reduces its ability
to extract nutrients from feedstuffs requiring more
prolonged digestion.

25. PIGS DIFFER FROM CHICKENS
* The pig has a stronger sense of
taste, so palatability is ofgreater concern
with swine than with poultry.
* Poultry have a shorter intestinal
tract but compensate by moving digesta
back and forth within it more effectively
than pigs and thus enhance nutrient ab-
sorption.
* The rate ofpassage ofmaterial
throughout the gut ofthe pig is slower
than that of the chicken. This helps the
pig increase its nutrient absorption.
E3 SMALL INTESTINE (18.3 M)
D CECUM (0.2 M) � COLON (5.0 M)
Figure 2-2b. Length of the Gastrointestinal Tract.
Adapted from E.T. Moran, 1982.
* Chickens have a smaJler total
Figure 2-2a. Capacity of the Gastrointestinal Tract.
capacity in the large intestine than pigs,
and thus the contribution ofmicrobial
fermentation is reduced.
The physiology of the gastrointestinal tract ofthe
pig plays an important role in determining what
constitutes a good or bad diet. Figure 2-2 illustrates
the size and capacity ofvarious segments ofthe
gastrointestinal tract in the fully grown pig.
Secondly, chewing mixes saliva into the food.
The saliva lubricates the material to make swallow-
ing easier. It also contains digestive enzymes which
initiate the breakdown ofthe food bolus. For
example, an enzyme called amylase, which helps to
break down starches, is a component of saliva. The
amount ofstarch digestion occurring in the pig due
to salivary enzymes is not substantial. It has been
estimated that the quantity of salivary amylase is
less than 0.001 percent that ofpancreatic amylase.
The Stomach
Once food enters the stomach, the next phase of
digestion begins. The stomach serves as a large vat
in which food is mixed with acid and digestive
enzymes plus a substance called intrinsic factor.
Because the stomach secretes acid into itself, its
structure must be such that it does not digest itself!
Mother nature works in wonderful ways, and in this
case, the stomach also produces a mucous-like
substance that lines the stomach and helps prevent
acid from damaging it.
Eating and Swallowing
Digestion offood actually begins in the mouth
where chewing accomplishes at least two important
objectives. The grinding action ofthe teeth serves
to break down food particles into smaller pieces to
facilitate swallowing and to increase their exposure
to digestive enzymes.
33.5%
29.2%
D CECUM (1.6 L)
� COLON (8.7 L)
[ill STOMACH (8.0 L)
§ SMALL INTESTINE (9.2 L}
7

26. Acid secreted in the stomach serves to alter the
structure of food proteins making them more
accessible to digestive enzymes and initiating the
action ofcertain digestive enzymes. For example,
the stomach secretes a compound called
pepsinogen. When pepsinogen is exposed to the
acid of the stomach, it is converted into pepsin, a
very potent enzyme involved in the digestion of
proteins.
The intrinsic factor is an interesting compound
also secreted by the stomach. It is absolutely
critical in the prevention ofa disease called perni-
cious anemia, which is due to a vitamin B12
defi-
ciency. The intrinsic factor must bind to the
vitamin B12
supplied by the diet ifthe vitamin is to
be absorbed. Supplements ofthe vitamin will not
prevent pernicious anemia ifthe intrinsic factor,
which cannot be added to swine diets, is not present
to allow for its absorption.
The secretory activity ofthe stomach must not be
underestimated. For example, in one study, 40 kg
pigs were found to secrete four to eight litres of
total fluid per day.
A major role ofthe stomach is to control the rate
ofentry offood into the small intestine and thus
contribute to a more gradual supply ofnutrients
from the gut. After a single meal, the stomach can
mete out digesta to the lower gut over a period of
18 hours or more.
It has been postulated that in the young pig, the
formation ofthe 'milk clot' in the stomach is
critical in slowing the entry offood into a relatively
immature small intestine. The problem with diets
containing little or no milk is that clotting is im-
paired and transit time is increased. An excessive
rate of passage of food into the small intestine
overloads the system. The problem is compounded
by the reduced digestive abilities ofthe small
intestine ofthe young pig. This is extremely
important to consider at the time of weaning. Once
poorly digested material overwhelms the gut,
undesirable bacterial fermentation begins and
scouring results. lt is recommended that recently
weaned pigs fed non-milk diets should be limit-fed
for five to seven days to help prevent scouring.
8
In summary, the stomach ofthe pig secretes acid,
pepsinogen and intrinsic factor which all contribute
to the digestion and absorbtion offood. The stom-
ach also acts as a regulator offood entry into the
small intestine, helping to prevent either overloading
or deprivation.
The stomach ofthe pig is susceptible to ulcers,
especially in the esophageal region. Ulcers are
common in growing and adult swine, although most
producers do not recognize the problem until death
occurs. Symptoms ofbleeding ulcers include dark
feces and anemia, both due to the loss ofblood into
the intestinal tract. Animals with a chalky, white
colour may also have a bleeding ulcer. Ulcers can
impair growth in swine and in severe cases, result in
death. Detailed information on ulcers is surprisingly
limited, but it is suggested that economic losses are
greater with subclinical ulcers which reduce animal
performance, than from death loss itself.
The cause ofgastric (stomach) ulcers is not really
known. Many factors are associated with them but
more research needs to be carried out in this area.
CURRENT THEORIES ON THE
CAUSES OF ULCERS
* Some suggest that "stress" is involved but
this has not really been studied nor quantified.
* Diet type may be involved with wheat and
corn showing more ofa connection with ulcers
than barley or oats. This may be due to their
different fibre contents.
* Pelleted diets may also contribute to ulcers
and yet the number of animals fed pelleted diets
without apparent problems suggest that it is not
the sole cause. The fine grind required to manu
facture firm pellets is probably more of a factor
than the pelleting process itself.
* Other dietary factors that may be involved
include fineness ofgrind, the presence of milk
proteins, high fat content, especially of unsatu
rated, long-chained triglycerides and deficiencies
in thiamine and vitamin E.
* Ulcers also appear to be a greater problem in
minimum disease herds, possibly because other
health problems are reduced or because animal
performance is higher.

27. Photo 2 - I.
Cross section of the intestinal tract, showing the villi
extending into the lumen of the gut(top). The mus-
cles of the gut, which allow it to mix and move its
contents, appear at the bottom of th� photo. The
micro-vllli, too smaJI to be seen in this photo appear
opposite.
An outbreak of ulcers can be treated by adding
coarse fibre to the diet. Oats appear to be particu-
larly effective. The inclusion of 10% whole oats
even in pelleted diets is beneficial, although pellet
quality will suffer. If oats are added, adjustments
need to be made to the diet to account for the drop
in energy. In some cases, long hay can be offered to
affected pigs to increase the fibre level in their diet.
but this is generally impractical in barns with liquid
manure systems. A coarser grind ofthe total grain
in the diet may also prove helpful. The topic of
grinding is covered in more detail in Chapter I 0.
9
Photo 2 - 2.
A more powerful microscope shows the micro-villi
(top) typical ofthe small intestine. The dark oblong
structures below the micro-villi are called
mitochondria; they act like little power plants to
drive the many activities of the gut.
The Small Intestine
The small intestine works in conjunction with a
number oftissues to achieve its objectives of
digestion and absorption ofas much food as possi-
ble. For example, it accepts digestive enzymes
from the pancreas to supplement those it manufac-
tures itself. Tt gets bile from the liver to assist in the
absorption of fats and fat soluble vitamins. Many
hormones produced throughout the body regulate
the activity ofthe small intestine in relation to
feeding, appetite and other external signals. As
well there are internal stimuli, such as gut fill and
the presence ofcertain materials in the gut which

28. also help to regulate its activity. It is quite clear
then that the small intestine does not work in
isolation, but is influenced by many other tissues in
the body. Once food enters the small intestine from
the stomach, digestion speeds up and absorption
begins. More enzymes are added to the digesta, as
well as mucous, buffers and bile. Some of the
enzymes are produced locally by the intestine;
others arrive from the pancreas.
Specific enzymes have specific roles to play.
Carbohydrates, such as starches and sugars, are
broken down by the action ofenzymes which are
very specific with respect to the carbohydrates they
will attack. Amylase breaks down starches such as
those found in grains. Sucrase degrades sucrose
(table sugar) and lactase degrades the 'milk sugar',
lactose.
Proteins are digested by a totally different set of
enzymes. Proteins must be broken down into
amino acids before crossing the intestinal wall.
Protein digestion begins in the stomach but be-
comes much more effective in the small intestine.
Examples ofprotein-degrading enzymes include
trypsin, chymotrypsin, elastase and
carboxypeptidase. The protein-degrading
(proteolytic) enzymes attack proteins at very spe-
cific locations in their structure.
Fats in the diet must also be digested before
being absorbed. An enzyme called lipase, derived
from the work lipid which is another name for fat,
breaks fats into smaller parts which are then com-
bined with bile salts to form a compound that can
cross the intestinal barrier. Bile salts are produced
in the liver and are an absolute necessity for proper
fat digestion.
lt can be seen that a very competent system has
been devised to allow the pig to digest the various
components in the diet. Failure of any part of this
system will result in impaired utilization of food. It
is a complex system, with details far beyond the
scope of this book. lt is important, though, to
recognize that digestion is not a simple matter and
that what and how we feed the pig, how we house
it, how old it is and how healthy it is can all influ-
ence the final outcome of the digestive processes.
10
The structure ofthe small intestine is uniquely
designed to accomplish its objectives ofdigestion
and absorption of nutrients. The walI is heavily
muscled which permits the intestine to expand and
contract in a rhythmic manner to move material
along its length and to assist in mixing enzymes,
bile and other secretions into its contents. The
process also ensures that material ready for absorp-
tion is brought into contact with the absorptive cells
found along the intestine surface. The constant
mixing motion is absolutely critical ifthe process of
absorption is to be efficient.
The small intestine is designed to maximize
absorption. The surface consists offiner-like
projections called villi which increase the surface
area ofthe gut and thus increase its absorptive
capacity. Along the villi are further projections,
called microvilli which also increase surface area
and thus, the absorptive capacity ofthe small
intestine.
Another interesting feature ofthe small intestine
is the way in which the absorptive cells grow. They
are called enterocytes and are formed at the base of
the villi and then migrate up along its surface as
they mature. The maturation process is important
because the more mature these cells are, the greater
is their content ofdigestive enzymes. The migra-
tion ofenterocytes along the surface ofthe villi
from the base to the tip, ensures that the mature
cells receive maximum exposure to the contents of
the intestine; meanwhile, the immature cells located
at the base ofthe villi are protected rom the physi-
cal forces offood moving along the length ofthe
intestine. Once the enterocytes reach the tip ofthe
villi, they are sloughed offinto the lumen ofthe
intestine, to be digested and absorbed. These
sloughed offcells, together with enzymes secreted
into the intestine, constitute what are cal1ed endog-
enous protein. This endogenous protein has been
estimated to represent anywhere from 25 to 75% of
the protein digested and absorbed by the gut. The
diet makes up the remainder.
The cells have a very briefexistence even under
conditions ofgood health. The life expectancy of
an enterocyte in a one week old piglet is only two to
four days. Sometimes the enterocytes do not reach

29. Moving through
the lumen, feed Is
digested and absorbed
Into the body of the
pig. Muscles surround
the Intestinal tissue;
their contraction
moves the dlgesta
along the tract and
helps mix In digestive
enzymes.
DISCARDED CELLS
!1
Folds in the
intestine are lined
with projections called
villi. The villi
increase the surface
area, thus enhancing
both digestion and
, absorption.
-,
'>1--.
'�� �' "-.�� �<',<
."" , "� '$� '..o
":/ o 0}
-,
BLOOD VESSELS
�����2----/
The individual villus consists of
cells that form at the base and migrate
to the tip, where they are sloughed off
Into the lumen of the intestine. As the
cells migrate they mature, Increasing
their ability to break-down and absorb
nutrients from the lumen of the gut. It
takes a cell 2-5 days to move from the
base to the tip. Each day, literally
billions of cells are discarded along the
length of the pig's gastrointestinal
tract. The villi are also the site of
absorption, where nutrients pass
through the cells to enter the blood
stream.
THE SMALL INTESTINE OF THE PIG
NUTRIENTS ABSORBED INTO BLOOD
11

30. maturity, but are sloughed off into the intestinal
lumen prematurely. As a result, the 'oldest' cells in
the system arc still immature. Ifthis happens, the
digestive ability ofthe small intestine is impaired
due to the absence ofmature cells and their rich
source ofdigestive enzymes.
Several things have been shown to influence the
lifespan of absorptive cells. Research suggests that
one ofthe factors responsible for the post-weaning
lag in the young pig is a reduction in the length of
the villi. This results in a greater proportion of
immature intestinal cells with reduced digestive
capacity. Diet composition and feeding behaviour
may also affect the Iifespan of the cells. For exam-
ple, even a few days off feed wiU lower the rate of
cell turnover and impair the intestine's ability to
produce new cells.
"' 100
CD
.c..0 80Ill
.c
<
ell
60
'i 40
iii
CD
Cl
20
0
*- 0
Duodenum Ileum
- O,yMa!ter
- En11gy
- Nlltogan
To1•1 Tract
Figure 2-3. Nutrient Digestion Along the Gastrointes-
tinal Tract of the Pig.
What does all this mean in the day-to-day feeding
of pigs? A very relevant example is the post-
weaning Jag mentioned above. The stress ofwean-
ing with an associated drop in feed intake, appears
to have a negative effect on the structure ofthe villi
and thus, the function ofthe smaU intestine. Re-
moving milk form the diet impairs clot formation
and increases the flow ofmaterial from the stomach
into the small intestine. The small intestine is
unable to handle the material presented to it result-
ing in digestive upset. A further drop in feed intake
compounds the problem. Poor sanitation which
leads to increased stress from disease makes the
situation even worse. Various feeding regimes
designed to minimize this problem wilJ be dis-
cussed in Chapter 5.
Another feature ofthe small intestine and the
stomach which is relevant to practical nutrition is
their overall capacity. Size plays an important role
in determining the amount of food a pig can eat. It
has been estimated that the capacity of the small
intestine represents a major Limiting factor in young,
growing pigs and that among individual animals,
the length of the intestine is correlated with Lean
tissue growth. As a result, young pigs are fed a very
concentrated diet that maximizes the quantity of
digestible nutrients per unit of feed and thus, the
amount ofnutrients consumed per day by the
animal.
The Large Intestine
The large intestine plays an important role in the
processes ofdigestion and absorption. Figure 2-2
shows how the digested portion offood increases as
it passes along the intestinal tract. By the time the
digesta leaves the first part ofthe small intestine
called the duodenum, much of it remains to be
absorbed. Even as the food passes throught the last
segment ofthe small intestine called the ileum,
digestion and absorption still occur.
The major role ofthe large intestine, which
consists ofthe cecum and colon, is to absorb water
and certain minerals called electrolytes. Bacteria in
the large intestine break down undigested food and
help to extract more nutrients, especially energy,
from the feed ingredients. Complex carbohydrates,
supplied by fibre (roughage) in the diet, are con-
verted by the bacteria into volatile fatty acids.
These volatile fatty acids can be absorbed and used
as an energy source by the pig. The ability to utilize
more fibrous ingredients increases in older animals.
Sows for example, can utilize alfalfa hay more
efficiently than weanlings.
The B-vitamins, as well as vitamin K, are pro-
duced by these same bacteria. It is not clear,
though, to what extent the vitamins can be absorbed
12

31. by the large intestine. lf the vitamins are excreted
in the feces and re-eaten, they will then contribute
to the vitamin nutrition of the pig. Some people
believe that pigs housed on fuJly-slatted floors
which have Jess exposure to manure, have a higher
requirement for dietary vitamins. There is very
little scientific evidence to support this. The pru-
dent approach is to ensure that the diet is properly
supplemented with preformed vitamins to meet the
requirements of the pig. In this way, the pig is not
dependent on microbial fermentation to supply even
a portion of its vitamin requirements.
Some of the information in Figure 2-2 must be
interpreted with great care. It suggests that nitrogen,
and thus protein, is absorbed by the large intestine.
It is true that nitrogen is absorbed, but unfortu-
nately, not as amino acids. Thus, ifan essential
amino acid is not absorb from a feed by the end of
the small intestine, it will not be absorbed intact.
The large intestine does not have the ability to
absorb essential amino acids but rather absorbs
nitrogen as a simpler compound called ammonia.
Nutritionists who are measuring the proportion of
lysine or other amino acids digested from a given
feedstuffwill collect digesta as it leaves the small
intestine rather than collect the feces. This is done
quite painlessly by surgically placing a collecting
tube in the intestinal tract of the pig. Ifnutritionists
use feces to determine amino acid digestibility, their
results will be incorrect. The bacteria in the large
intestine break down lysine and other amino acids
and are also able to manufacture amino acids from
non-protein nitrogen.
Summary
It appears that about 20% ofthe intestinal tissue
turns over (is replaced with new tissue) every day!
In the pancreas, up to 75% of the tissue is replaced
daily. This compares with muscle which turns over
at a rate of 2 to 3% per day. It has been estimated
that 25% of the protein turnover in the total body
occurs in the gastro-intestinal tract.
Studying the physiology ofthe stomach, intes-
tines and related tissues in the pig provides ex-
tremely useful information on how the pig digests
and absorbs feed, and how different conditions
13
impair this activity. Simply stated, for best per-
formance, the pig should be fed a diet that is suited
to its digestive abilities. Since these abilities change
with age, the better quality and more expensive
ingredients should be used with the younger pig
than with the adult sow or boar.
Additional Reading and References
Lloyd, L.E., B.E. McDonald and E.W. Crampton.
1978. Fundamentals ofNutrition. W.H. Freeman
and Co., San Francisco. 466 pp.
Low, A.G. 1989. Research into the digestive
physiology ofpigs. In. (E.J. van Weerden and J.
Huisman, eds.) Nutrition and Digestive Physiology
in Monogastric Farm Animals. pp. 1 - 15, Pudoc,
Wageningen.
Moran, E.T., Jr. 1982. Comparative Nutrition of
Fowl and Swine: The Gastrointestinal System,
University ofGuelph, Guelph.
McDonald, P., R.A. Edwards and J.F.D.
Greenhalgh. 1973. Animal Nutrition. Oliver &
Boyd, Edinburgh.
Pond, W.G. and K.A. Korpet. 1978. The Biology
ofthe Pig. Cornell University Press, Ithaca.
371 pp.
Whittemore, C.T. 1987. Elements ofPig Science.
Longman Handbooks in Agriculture, Harlow.
181 pp.
Whittemore, C.T. 1993. The Science and Practise
of Pig Production. Longman Group, U.K. Ltd.,
Harlow. 661 pp.

32. 14

33. 3. NUTRIENTS
Although diets are mixed using ingredients,
what really matters to a pig are the nutrients
contained in those ingredients. The relative
proportions of barley, wheat, soybean meal, and
other feedstuffs in a diet are determined on the basis
ofthe nutrients they provide to a pig. When a
nutritionist formulates a diet for pigs, no less than
41 essential nutrients are considered.
The essential nutrients can be divided into
categories ofminerals, amino acids, vitamins, fatty
acids, energy, and water (Table 3-1 ). If a diet is to
be properly balanced, the nutritionist must know the
pig's requirement for each nutrient and the amount
supplied by each ingredient.
Table 3-1. Essential Nutrients in the Diet of a Pig.
In this chapter, the utilization ofnutrients by
pigs and means to estimate the available nutrient
levels in pig feed ingredients are discussed. For
information on nutrient allowances in diets for the
various classes of pigs, the reader is referred to
chapters 6 - 9. Water, which can also be classified
as a nutrient, is addressed in chapter 12.
What is a Nutrient?
Knowing the difference between a nutrient and
an ingredient, or feedstuff, is critical when
formulating a diet. A nutrient is a chemical
substance that is supplied by the diet and which pigs
need to stay alive. Nutrients perform specific
functions in the body and their absence or
deficiency will result in reduced productivity, health
problems and, possibly, death.
An ingredient or feedstuff is the material used to
supply nutrients. For example, barley and com are
ingredients which contain amino acids, energy, and
other nutrients. They can supply a pig with some of
the nutrients it needs. A balanced diet mixes
ingredients, such as com or barley, that supply the
nutrients in proper proportions. The pig has no
specific requirement for individual ingredients - it
does not need barley or com, specifically, in its diet,
for it can obtain the necessary nutrients from other
ingredients, such as canola or soybean (or in some
countries, even green bananas!). A pig may prefer
to eat one ingredient over another, but ingredients
have no unique role in a pig's diet. Selecting the
type of feedstuffs to supply nutrients is much less
critical than making certain the necessary nutrients
are supplied from the feedstuffs chosen.
15
Amino Acids Minerals Vitamins Other
* These amino acids are considered semi-essential
nutrients because they can be derived from methionine
and phenylalanine, respectively. Other nutrients, such as
vitamin C, linolenic acid, fluorine, chromium, nickel, lead
silicon, tin, and vanadium, may be essentiaJ in a pig's diet,
however, deficiencies are extremely unlikely and/or
requirements for these nutrients have not been clearly
established.
Nutrient Availability
Availability refers to the pig's ability to digest,
absorb, and utilize nutrients from a given
ingredient. Very few nutrients are 100% available.
A nutrient may be present in an ingredient but not
available to the pig for both mechanical (e.g.,
processing methods) and physiological (e.g.,
digestive functions, age, state of health) reasons.
Defining the availability for each nutrient in each
ingredient is a difficult task because availability
Arginine Macro Vitamin A Energy
Histidine Calcium Vitamin D Linoleic
Isoleucine Chloride Vitamin E Acid
Leucine Magnesium Vitamin 812
(Omega-6
Lysine Phosphorus Biotin fatty acids)
Methionine Potassium Choline Water
Phenylalanine Sodium Folic Acid
Threonine Sulphur Menadione
Tryptophan Niacin
Valine Micro Pantothenic Acid
Cystine* Cobalt Pyridoxine
Tyrosine" Copper Riboflavin
Iodine Thiamine
Iron
Manganese
Selenium
Zinc

34. 5
Figure 3-1. Pig Response to Level of Nutrient in the
Diet.
10
o..L.�---�------.....-..1,--.--r--.-....,....-r....,............,
o 2 4A s s
Nutrient Level In the Diet
*As the requirement (point A) is approached, the rate of
improvement per unit of nutrient decreases.
: .c
g_ 3
••a: 2
CII
a: 1
How docs the nutritionist work around this
problem? In many cases, sufficient information is
available to permit at least an educated guess. Diets
will often include more than one basal grain and
more than one protein supplement. Thus, the
nutritionist 'hedges his position' across a number of
ingredients, such that underestimating one might be
compensated by overestimating another. This
approach is not a totally desirable one, but until
more precise data becomes available, it is probably
the most practical one.
varies from ingredient to ingredient and is
influenced by many factors.
Nutrient Requirements
What is meant by the word 'requirement' from a
nutritionist's perspective? Traditionally, a
requirement has been defined as the amount ofa
given nutrient a pig requires to maximize
performance. Producers need to understand the
criteria used to determine requirements because
how the requirements are determined can influence
the way producers use nutritional information.
One ofthe frustrations in defining a requirement
is that maximum performance may occur at
different nutrient levels depending on the response
criteria being considered. For example, maximum
growth rate may require more or less ofan amino
acid than maximum feed efficiency. The amount of
a given nutrient required to maximize the immune
response may differ from the amount required for
maximum feed intake. Ifcarcass merit is used to
evaluate nutrient requirements, conclusions may
differ from those reached using growth rate.
Thus, requirement defines the level needed to
achieve maximum performance but not necessarily
maximum profit. Each situation must be evaluated
to determine the best (most profitable) feeding
strategy.
Although we would all like to have neat, simple
tables defining an absolute value, they are not
realistically possible. Some compromise must
occur. The compromise does not diminish the value
or importance ofnutrient requirement tables, it
merely emphasizes the importance ofunderstanding
their origin. Three excellent publications that
provide useful requirement guidelines are the
National Research Council's Nutrient Requirements
ofSwine (1988), the Agricultural Research
Council's The Nutrient Requirements ofPigs
(1981), and the Australian Agricultural Council's
Feeding Standardsfor Australian Livestock - Pigs
(1987).
Typically, in the case ofessential amino acids
and many minerals, the requirement is determined
by feeding a range oflevels ofthe nutrient and
determining the lowest concentration that
maximizes growth rate, feed efficiency, or some
other response criteria. The key word here is
'maximize'. Often, the pig's response to increasing
levels ofa nutrient becomes progressively smaller
as the requirement level is approached (Figure 3-1);
consequently, the cost of the last I 0% improvement
is much higher than the first 10%.
Energy
According to the definition given earlier, energy
is not truly a nutrient. Energy is a characteristic of
the organic nutrients (carbohydrates, fats, amino
acids) that are normally present in the pig's diet.
The energy released by burning a substance in a fire
is the same as the energy obtained by the body
when it metabolizes energy in a cell. The amazing
point is that, unlike an open fire which releases all
its heat, the body is able to 'capture' the energy that
is supplied by the diet and convert at least part of it
16

35. into forms the cell can use for various purposes.
Energy, due to the amount required, is generally the
most expensive 'nutrient' in the pig's diet.
Consequently, nutritionists focus considerable
attention on energy in feed formulation and feeding
management in order to minimize feed cost without
compromising performance.
energy is called net energy (NE). NE is the best
estimate ofthe amount ofuseful energy that is
supplied by feed ingredients.
Metabolizable Energy - Heat Increment= Net
Energy
Figure 3-2. Distribution of Dietary Energy.
Some scientists have attempted to use this
information on heat increment to practical
advantage by designing diets around heat
increments. The pig is a warm-blooded animal and
must maintain a constant internal body temperature
irrespective ofthe temperature ofits surroundings.
Normal metabolism generates heat that is used in
body temperature regulation. Ifa pig is chilled, it
must eat more feed to keep warm or else it will lose
weight or gain it at a slower rate. The heat
increment is used to provide some ofthis required
heat, so heat increment in a diet is desirable. The
pig will need less heat to maintain a constant body
temperature in hot weather and will actually lower
its feed intake to reduce the production of metabolic
body heat if it is in danger of becoming heat
stressed; in this case, heat increment in the diet is
detrimental. Obviously, in these two instances, pigs
will require diets with different heat increments.
The quantity ofheat increment varies depending on
the nature ofthe diet.
Production
Net energy
I
Metabolizable energy
I
IDigestible energy
I
Gross Energy
I
Maintenance
IFecal energy
Urinary energy
Heat increment
A portion of metabolizable energy is lost when
the pig uses the nutrients in the feed as heat, i.e. heat
losses during eating, digestion and actual nutrient
metabolism. This portion is called the heat
increment. Once the heat increment is used up out
of ME, the energy actually available to the pig for
maintenance and growth is left. This amount of
Gross Energy - Fecal Energy = Digestible Energy
_Some ofthe digestible energy is lost in the pig's
unne or released as gas from its gastro-intestinal
tract. Much ofthe energy lost in the urine results
from the excretion ofunneeded nitrogen
compounds, such as urea. The amount ofdigestible
energy remaining in the pig after these losses is
called metabolizable energy (ME).
Digestible Energy - (urine energy loss+ gas energy
loss)= Metabolizable Energy
Energy Components
The total quantity ofenergy contained in a
feedstuffcan be partitioned into different
components based on how the pig will use the
energy (Figure 3-2). Ifan ingredient, such as barley
or wheat, is burned completely, the amount of
energy released is called gross energy (GE). The
gross energy content can be determined by the
bomb calorimeter. GE is thus the total amount of
energy contained in the grain; ifthe pig could digest
and utilize 100% ofthe energy, that is how much
would be available. The pig, however, digests or
absorbs only a portion of the gross energy. The
energy absorbed by the intestinal tract and actually
available to the pig is called the digestible energy
(DE). The DE content of any feedstuffcan be
determined by measuring the quantity offood
(energy) consumed and subtracting the energy lost
in the feces (calculated by weighing the feces and
analysing their composition).
17

36. The solution proposed by some scientists is to
feed a diet high in heat increment (rich in fibre)
when the pig is likely to be chilled. When the pig is
likely to be heat stressed, a diet low in heat
increment (rich in fat) is recommended. Under
Canadian conditions, this feeding approach means
feeding a high-fibre diet to dry sows in chilled
conditions, such as in outside housing in winter or
in a cool gestation barn (especially barns equipped
with individual stalls where sows cannot huddle to
keep warm). A high fibre diet is never fed to
weanling pigs, lactating sows, or growing pigs
because growth rate would suffer. In the heat of
summer, lactating sows and growing pigs should
receive a diet rich in fat to help maintain energy
intake. Ofcourse, these suggestions must be
considered in the context ofcost and economic
benefit.
Although net energy is the best estimate ofhow
much useful energy is supplied by a diet, it is rarely
used as a system for formulating swine diets in
North America because of the difficulty in routinely
and accurately determining the heat increment of
feeding when different ingredients are fed to pigs.
NE systems are used more commonly in European
countries, where a larger variety of ingredients are
used to formulate swine diets.
Table 3-2 shows the GE, DE, ME, and NE
content in selected pig feed ingredients. Most of
the ingredients listed are very similar in GE content.
There are, however, some important differences in
DE content, both expressed in absolute values as
well as in fractions ofGE content. In fact, barley
contains more GE but Jess DE than com. This
clearly indicates that it is more accurate to
formulate pig diets based on a DE basis rather that
on a GE basis.
The proportion ofdigested energy lost in the urine
is fairly constant for all grains and all protein
sources, but differs between these classes of
ingredients. This difference is due in part to the
urinary energy lost during excretion ofnitrogenous
waste products. Because ofthe differences between
protein sources and grains, there are theoretical
advantages to using ME values in preference to DE
values to formulate feed. However. note that many
of the published ME values have merely been
derived mathematically from DE. Direct assays
(analyses) ofME are difficult since measuring the
amount ofenergy excreted in the urine poses a
number of logistical problems. Whether DE or ME
is used, be certain that both requirement and
nutrient values are expressed in the same system.
The values in Table 3-2 demonstrate that the
differences in NE content between feedstuffs tend
to be larger than the differences in DE content. For
example, in a DE system. corn contains 12% more
energy than barley. In a NE system, this difference
increases to 15%. For ingredients with extreme
compositions such as alfalfa and wheat shorts (high
in fibre) or soybean oil (high in fat), these differ-
Table 3-2. Proportions of Gross Energy (GE), Digestible Energy (DE), Metabolizable Energy (ME) and Net
Energy (NE) in a Sample of Ingredients.
GE DE ME NE DE:GE ME:DE NE:ME
Alfalfa Meal 3830 1880 1705 540 .49 .91 .32
Barley 4395 3120 3040 1980 .71 .97 .65
Corn 3945 3490 3380 2270 .88 .97 .67
Wheal 3965 3360 3200 2215 .85 .95 .69
Wheat Shorts 4060 3025 2835 1795 .75 .94 .63
SBM 47% 4260 3680 3385 1760 .86 .92 .52
Soybean Oil 9395 7560 7280 5500 .80 .96 .76
Derived from: Ewan, 1989; Energy metabolism offarm animals. EAAP publication No.. 43. Pudoc Publishers,
Wagcningcn,The Netherlands.
18

37. ences are even more apparent. This again illustrates
that, in theory, it is more accurate to formulate diets
using an NE rather than DE or ME system.
Energy is measured in units ofeither calories (cal)
orjoules (J). The term used in this book is the
kilocaloric, equal to 1000 calories. Thejoule is
more common in Europe and is becoming more
popular in Canada, but is not yet universally
accepted. One calorie equals 4.184 joules.
hemicellulose, and lignin, which are essentially
indigestible by swine. ADF consists only of
cellulose and lignin. ADF and NDF were
developed to evaluate forages for ruminant species.
They have also been found valuable by swine
nutritionists but tend to underestimate the total fibre
ofcereaJ grains.
Table 3-3. Fibre Content of Ingredients Used in Swine
Diets.
Energy Sources Ingredient
Dietary energy is derived from three sources:
carbohydrates, fats, and amino acids. The term
carbohydrate includes simple sugars and starches,
such as table sugar or the starches found in flour,
which are all highJy digestible. Carbohydrates also
include more complex compounds, such as fibre,
which is difficult to digest, and thus a poor energy
source.
Content(%)
Dietary Crude
Fibre NDF ADF Fibre
Barley 19 15 5 4
Corn 9 8 2 2
Peas 16 10 7 5
Soybean meal 24 15 9 8
Wheat 11 10 3 2
Defining the term fibre has been a source of
controversy for decades. For the purposes of this
book, fibre is defined as the portion of carbohydrate
in a diet that cannot be digested by the enzymes
produced by a pig. Pigs, like ruminants, rely on
bacteria that are present in the digestive tract to utilize
dietary fibre. The pig does not have a requirement
for fibreperse, although it provides a texture in diets
that helps digestive processes. Fibre is used to evaluate
ingredient quaJity because it is associated with reduced
DE content and impairedutilization ofother important
nutrients. Therefore. from a nutrient perspective, fibre
has a generally negative impact onanimal feed quality.
Measuring fibre in feed ingredients is an area of
active research. Table 3-3 defines the fibre content of
some common ingredients. The complex nature of
fibre is illustrated by the number of fibre values
defined. Dietary fibre is a Swedish tenn that includes
lignin (a highly indigestible carbohydrate found in
such feedstuffs as straw) plus all complex sugars not
found in starch.
The detergent system, developed by P.J. van Soest
in the United States, differentiates between two
kinds offibre: acid detergent fibre (ADF) and
neutral detergent fibre (NDF). NDF includes
material in the plant cell wall, notably cellulose,
Adapted from: Graham 1988. Anim. Plant Sci. 1 :76-80.
There are large differences in the values obtained
by these measurements, although they all attempt to
define the same component of feed ingredients -
indigestible carbohydrate. Most Canadian feed
testing laboratories report crude fibre, although acid
detergent fibre and neutral detergent fibre
measurements are gaining popularity.
The ether extract (fat) content ofa feedstuffor
diet is important because fat is rich in energy. All
other factors being equal, the higher the fat content
in a diet, the more digestible energy it will contain.
Determining fat content provides some insight into
how much energy is present. Fat content is
estimated by determining the portion ofthe sample
that is soluble in petroleum ether. This procedure is
a standard one, but misses some important
compounds. such as energy-rich phospholipids. In
barley, for example, these phospholipids represent
as much as 25% ofthe total fat in barley grain and
contribute to its total energy.
Ether extract will also include such components
as waxes and pigments, which are of little
nutritional value. For this reason, the digestibility
19

38. Feedstuff
Alfalfa meal
Barley
Com
Soybean meal
Meat meal
Wheat
Wheat bran
Percent
Digestibility
54
86
80
80
93
52
58
Estimating Energy Contents in Feeds and
Feed Ingredients
Evaluating the content ofenergy and other
nutrients in feed ingredients is an important step in
formulating diets for swine. Without knowing the
amounts of nutrients supplied by individual
ingredients, one cannot, with any degree of
certainty, put together diets that will satisfy the pig's
needs. Unfortunately, there is a considerable
amount ofvariation in available energy contents
between different samples of one feedstuff. For
example, recent research at the Prairie Swine Centre
demonstrated that DE content varied by as much as
l0% between various samples ofsubstandard
wheat, with the poorest sample similar to that in
regular barley. This demonstrates the use of
average book values is not sufficient to estimate
nutrients in specific samples offeed ingredients.
However, it is simply too expensive and time-
consuming to evaluate the nutritional value of
feedstuffs in feeding trials. There is thus a need for
rapid, inexpensive, and practical tests for use in
day-to-day diet formulation. Laboratory (chemical)
evaluation can be ofgreat assistance in meeting this
need. World-wide research has attempted to
develop chemical and alternative tests that give the
true nutrient composition of ingredients and mixed
diets, and accurately reflect the true feeding value.
Table 3-4. Digestibility of Ether Extract of
Common Feedstuffs.
ofthe ether extract varies among grains as they vary
in the relative proportion of phospholipids and
waxes (Table 3-4).
What is the solution? Some nutritionists use
di ITcrent solvents in place of petroleum ether to
extract the fat of feed grains thus developing a more
complete analysis. Common alternative solvents
include diethyl ether, and a 2: 1 mixture of
chloroform and methanol. Different solvents arc
used to answer different questions. As in most
analyses, there is no complete test for all answers.
Adapted from: Animal FeedstuffTable. 1991. Centraal
Veevoederbureau, Runderweg 6, 8219 PK Lelystad, The
Netherlands.
Amino acids supply energy only when they are
not used for protein synthesis. Animals prefer to
use amino acids to produce body protein. Amino
acids supplied in excess ofthe animals'
requirements for the synthesis of body protein or
other nitrogenous compounds are degraded and
used as an energy source. Since protein is a very
expensive energy source, excess amino acids should
not be added to a diet intentionally to help meet the
pig's energy requirements. Much cheaper energy
sources, such as carbohydrates, are preferred
wherever applicable in a diet. In addition, some of
the energy derived from amino acid degradation is
required for the excretion (through urine) of
nitrogenous compounds that are derived from
amino acids. This requirement reduces the amount
of available energy that can be derived from
degraded ammo acids.
An example ofthe progress made in this area is
the use ofnear infra-red analyses (NTRA) to
evaluate feed samples. Nutrient levels are estimated
based on the feed sample's absorption of specific
wavelengths of infra-red light. However, in order to
properly calibrate NIRA equipment, large numbers
ofsamples which enclose the entire range of
samples to be tested and with known nutrient
contents and availabilities arc required. An
alternative means to estimate available energy
content in ingredients, as well as in complete feeds,
is to chemically determine the content ofvarious
nutrients that supply energy (fat, protein, various
fractions ofcarbohydrates such as starch sugars and
specific fibres) as well as GE, and to use this
information to predict its available energy content.
For example, the following equation, developed by
French researchers. can be used to estimate the DE
content in complete pig diets.
20

39. DE (Kcal/kg of dry matter)*= 4168 - (9. lx Ash)+
( 1.9 x Crude Protein)+ (3.9 x Ether Extract) - (3.6
x NDF)**
*The contents ofthe chemical constituents in the diet are
expressed in grams per kg of dry matter.
**NDF - Neutral Detergent Fibre
In Chapter 4, various equations will be presented
that can be used to predict DE content in specific
samples ofmain feed ingredients.
Table 3-5. Effect of Bushel Weight on Nutrient
Content of Cereal Grains.
Bushel Crude Crude Ether
Weight Protein Fibre Extract
kg (lb) -%-
23 (5 I) 9.2 8.5 2.4
22 (49) 10.4 7.6 1.8
20 (45) 10.6 8.9 2.5
19(42) 11.0 9.6 2.5
Table 3-6. Minimum Recommended Bushel Weights
for Grains Used in Swine Rations.
Guidelines for minimum bushel weights ofgrains used in
swine diets. [f grains below these standards are used,
adjustments in energy content should be made.
Table 3-6 offers guidelines for minimum bushel
weights ofcereal grains destined for use in swine
diets.
Energy Requirements
A pig requires energy for almost all its body
processes. Amino acids cannot be converted to
muscle proteins and feed cannot be digested or
wastes eliminated without energy. Body
temperature cannot be maintained , gestating sows
cannot produce a fetus, nor can nursing sows
produce milk without energy. Clearly, energy is
fundamental to all life.
43
50
55
48
56
60
Bushel Weights (lb)
Standard Minimum
Grain
Barley
Com
Wheat
A common misconception is that bushel weight
is a good indicator of a cereal grain's nutrient
quality, and DE content in particular. Premiums are
sometimes paid for grains that exceed normal
bushel weights, e.g., 23 kg (50 lb) barley or 26 kg
(58 lb) com. Unfortunately, like many of the .
factors used in the grading ofgrains, bushel weight
is not a good indicator of feed value. Test weight
can be affected by many factors, such as the shape
and surface dimensions ofindividual kernels, which
do not necessarily reflect nutrient content.
Research results show very clearly that energy
concentration ofgrains does not fall in proportion
with bushel weight. The energy content oftypical
50 lb of barley is no different than that of48 lb or
even 46 lb of barley. In a recent study at Prairie
Swine Centre, there was no relationship between
DE content and bushel weight in wheat samples that
varied in density between 53 and 63 lb/bushel. In
the case ofvery low bushel weights, energy values
do appear to fall; therefore, very low bushel weight
grains should be used only in diets where energy
concentration is not critical (gestating sows or
growing pigs over 60 kg body weight) and even
then the concentration ofother nutrients needs to,
be adjusted to reflect changing energy levels.
The rise in crude fibre coinciding with falling
bushel weight is often put forward as an argument
favouring the use of bushel weight as an indicator
ofgrain quality. However, the rise in crude fibre,
which is low in energy, appears to be offset by a
similar rise in fat, which is high in energy (Table 3-
5). Interestingly, bushel weight has been used as an
indicator of flour yield, but even this relationship is
suspect.
A pig's requirement for energy will be determined
by a number of factors. The pig's size is important
because energy needed for maintenance is directly
related to body size. It 'costs' more in terms of
energy to maintain a 250 kg sow than a 180 kg sow.
The pig's productive state is also an important
factor. A lactating sow requires more energy than a
gestating sow since she is producing large quantities
of milk. A pig that is gaining weight requires more
21

40. energy than one that is not growing. As described
previously, the environment in which a pig is
housed is also critical. In cold temperatures or wet,
drafty conditions, energy required to maintain body
temperature rises. Jf pigs can huddle with each
other, their energy requirements in cold weather are
lower than if they arc penned individually.
The amount of energy required in feed is
determined by considering both quantity offeed
consumed per day and amount ofenergy required
per day. This principle is important. For example,
a man working at a job that involves considerable
physical exertion has a high energy requirement per
day. In theory, this requirement could be met by
eating an enormous quantity of lettuce or other
bulky, low energy, foods. In practice, this approach
will not work because the man simply cannot
physically consume enough lettuce to meet his
energy needs. If he is given a diet of meat and
potatoes, i.e., high energy foods, he can easily
consume enough food to meet his daily energy
needs. The message here is that gut capacity plays
an important role in formulating diets.
The same principle applies to pigs. Ifthe
concentration ofenergy in the diet is too low, the
pig may be unable to consume sufficient amounts to
meet its energy needs. A gestating sow is fed less
than her appetite demands to prevent excess weight
gain. Her stomach capacity is more than sufficient
to meet her energy needs with most practical diets.
Conversely, the lactating sow has a very high energy
requirement to support milk production and
maintain her body condition in preparation for the
subsequent breeding period. Ifshe is fed a low
energy diet, she will be unable to consume
sufficient energy per day, will lose body weight, and
produce less than her maximum potential ofmilk.
Pigs up to about a 60 kg body weight ( 130 lb)
being fed traditional ingredients may be in danger
ofgrowth retardation because their gut capacity is
insufficient to accommodate the energy required for
them to grow quickly. In pigs with extremely high
(lean) growth potential, such as boars, energy intake
may limit growth up to higher body weights.
However, in most finishing pigs of 60 kg or heavier
body weight, gut capacity no longer places a limit
on growth, assuming normal ingredients are used.
Because of limitations in gut capacity relative to
energy needs, diets with a high concentration of
energy should be fed to younger pigs and lactating
sows. These are called high nutrient density diets.
Lower energy grains, such as oats, are too low in
energy to support maximum growth rate.
Refer to the specific chapters on feeding various
classes ofpigs for further information on energy
requirements. Any general requirement must
consider many variables, such as environmental
temperature, desired performance, body size, and
some score of genetic capacity.
Amino Acids
Amino acids are the building blocks ofprotein,
meaning that all proteins are made up of individual
amino acids linked together like beads in a
necklace. In nature, there are about 22 amino acids
that can link together to form proteins. Pigs can
produce some of them from other substances; but
they cannot synthesize 10 amino acids so they must
be provided by the diet. These 10 amino acids are
called the 'essential amino acids' (Table 3-1). If
they are not present in the diet, or are present in
insufficient quantities relative to need, the animal
will be unable to grow properly.
In addition to the 10 essential amino acids, there
are two so-called semi-essential amino acids,
cystine and tyrosine, that can be synthesized only
from essential amino acids, methionine and
phenylalanine, respectively. The term 'total sulphur
amino acids' (T.S.A.A.), refers to the sum of
methionine plus cystine. Pigs require T.S.A.A. in
addition to the requirements for methionine. This
requirement indicates the importance ofmonitoring
both methionine and cystine levels in swine feeds.
At least 50-55% ofthe total T.S.A.A. requirements
must be supplied by methionine. In the same
manner, phenylalanine must supply approximately
55% of the animals' requirements for phenylalanine
plus tyrosine. The sum ofphenylalanine and
tyrosine is also referred to as "total aromatic amino
acids". Phenylalanine and total aromatic amino
acids are rarely deficient in practical diets.
Consequently, under practical conditions, tyrosine is
much less important than cystine.
22

41. When the pig eats protein as part of its diet. the
intestinal tract breaks down protein into individual
amino acids. These amino acids are then
transported into the blood and carried to various
tissues where they are used for a variety of
purposes. The most obvious function is to form
muscle protein. However, a host of other proteins
in cells are just as important since they support a
wide range ofessential body functions. Enzymes,
such as those that help to digest food in the gut, or
those that help ensure that overall metabolism in
tissues flows smoothly, are proteins. There are also
carrier proteins that transport nutrients from one
side of the cell wall to the other. Haemoglobin in
the blood is a protein; it transports oxygen from the
lungs to the tissues to support cell metabolism. The
blood also contains many other proteins, such as
those which transport certain vitamins or minerals.
Milk contains proteins to nourish newborn piglets.
Immunoglobulins circulating in the blood protect
animals against specific forms ofdisease.
Although protein synthesis is important,
individual amino acids also perform other
functions. For example, tryptophan is converted
into serotonin, a chemical called a neuro-
transmitter, that is involved in the transmission of
signals by the nervous system. It is this function
that has prompted some people to recommend
tryptophan supplements as a calming influence in
the diet. Tryptophan can also be converted to the
vitamin niacin. thereby reducing, but not
eliminating, the need for niacin in the diet.
Estimating Protein and Amino Acid
Contents in Feeds and Feed Ingredients
The crude protein content is an estimate of the
amount ofprotein present in a feed ingredient or
mixed diet. Since amino acid analysis is very
expensive and time-consuming, crude protein has
been adopted as a more practical indicator of feed
value. Direct analysis for amino acids will become
a much more common procedure in the future.
Crude protein is usually measured using the
Kjeldahl method. According to this very old, but
simple and accurate method, feed is digested in acid
and the quantity oftotal nitrogen in the sample is
determined. The total nitrogen value is then multi-
plied by the 'Kjeldahl' factor of6.25 to generate the
crude protein value.
The crude protein content of feedstuffs must be
interpreted with great care for three main reasons:
The true Kjeldahl factor varies from ingredient to
ingredient; not all ofthe nitrogen in a feed sample is
associated with true protein; and total protein is a
very rough estimate ofthe amino acids present.
The first point The true Kjeldahl factor varies
from ingredient to ingredient. The Kjeldahl factor
of6.25 assumes that the protein in the sample
contains 16.0% nitrogen. This assumption is not
necessarily true. As mentioned previously, protein
consists of individual amino acids. The proportion
of nitrogen in each amino acid varies from 7.7 to
32.2 (Table 3-7) so the actual amount ofnitrogen
present in a protein will depend on the relative
proportions ofeach amino acid in the protein. As
the proportion of amino acids change, so will the
average proportion ofnitrogen in the final protein.
Com protein contains I 6.0% nitrogen while the
protein in wheat or barley contains about 17.2%
nitrogen. Therefore, the correct factor for wheat
and barley is 5.83. Using 6.25 for these two cereals
will overestimate protein content by about 7%.
However, the standard Kjeldahl factor is neces-
sary because the proper nitrogen correction value is
not always known. For example, ifa pork producer
submits a mixed feed for analysis, what value
should be used to adjust nitrogen to crude protein?
A universally accepted standard is required and
6.25 has become that accepted standard.
23

42. Table 3-7. Nitrogen Content ofAmino Acids.
Amino Acid % Nitrogen
.Methionine 9.4
Cystine 11.6
Lysine 19.2
Tryptophan 13.7
Phenylalanine 8.5
Leucine 10.7
lsoleucine 10.7
Threonine 11.8
Valine 12.0
Histidine 27.1
Arginine 32.2
Glycine 18.7
Asparagine 21.2
Aspartic Acid 10.5
Serine 13.3
Glutamine 19.2
Glutamic Acid 9.5
Proline 12.2
Alanine 15.7
Tyrosine 7.7
The second point: Not all ofthe nitrogen in a
feed sample is associated with true protein. Some
ofthe nitrogen in feed ingredients is in the form of
non-protein nitrogen. There are compounds that
contain nitrogen but are not protein. Including them
in the crude protein calculation will overestimate
the quality ofthe ingredient. The information in
Table 3-8 summarizes these two points. It provides
the 'corrected' Kjeldah1 factor, two crude protein
values (one obtained from the standard Kjeldahl
factor, one from the corrected factor) and the
corrected crude protein value adjusted for non-
protein nitrogen.
The third point: Total protein is a very rough
estimate ofthe amino acids present. Total protein,
even adjusted for non-protein nitrogen and using the
corrected Kjeldahl factor, is not a perfect indicator
ofamino acid content. For example, in cereal
grains lysine contributes to approximately 4% of
corrected protein, while in soybean meal this value
exceeds 7.5%. As lysine is generally the first
limiting amino acid in pig diets, this means that
protein in soybean meal is close to two times more
valuable than cereal grains in meeting the pig's
amino acid requirements.
Table 3-8. Protein Estimation Adjusted for Corrected Nitrogen Factors and Non-protein Nitrogen Content.
Corrected Crude Protein (CP) Non-protein Corrected
Feedstuff Factor N x 6.25 N x Corrected Nitrogen Protein
Factor (% ofCP)
(%)
Barley 5.83 10.6 9.89 18.2 8.09
Canola Meal 5.53 37.7 33.36
Com 6.25 8.5 8.50 22.2 6.61
Milk, Fresh 6.38 3.3 3.40 11.1 3.01
Oats 5.83 10.8 9.79 25.0 7.34
SBM 5.71 47.5 43.40 18.4 35.41
Wheat 5.83 13.5 12.59 16.7 10.49
Wheat Bran 6.31 15.5 15.65 20.0 12.52
Source: unknown.
24

43. We do not suggest eliminating the crude protein
measure since it is a simple, rapid, and inexpensive
test which is required to provide an estimate of
protein quality. However, failure to consider the
underlying principles could lead to serious errors in
diet formulation. For greatest precision, crude
protein should be used in conjunction with
estimates ofamino acid composition.
The pig requires amino acids that make up
protein. It is possible to analyse ingredients for
their amino acid content but it is an expensive
procedure that costs as much as $150 per sample.
How then can diets be formulated on the basis of
amino acids, when such anaJyses are so expensive?
Nutritionists have a number ofoptions open to
them. Most use book values for amino acids.
These vaJues will be vaJidated from time to time by
amino acid anaJyses to confirm their accuracy.
Nutritionists also use 'prediction' equations to
adjust individual amino acid content based on
changes in nitrogen content. Prediction equations
are becoming more common and, as further studies
are completed, will improve in accuracy. At this
time, however, they must be used with caution.
The following regression equations can be used
to estimate the amino acid content ofcommon
grains and protein sources.
(Courtesy: Degussa Corporation)
The ingredients tested to obtain these equations
were not necessarily all Canadian.
Barley (Canadian. N=59 samples)
% Lysine=% CP x 0.0269 + 0.097; r = 0.91
% Methionine=% CP x 0.0154 + 0.027: r = 0.95
% T.S.A.A. = % CP x 0.0304 + 0.118: r = 0.92
% Threonine - % CP x 0.0318 + 0.029; r = 0.96
% Tryptophan = % CP x 0.0076 + 0.051: r = 0.76
Wheat (N=l48 samples)
% Lysine=% CP x 0.0194 + 0.094; r = 0.82
% Methionine=% CP x 0.0163 + 0.009; r = 0.87
% T.S.A.A. = % CP x 0.0343 + 0.042; r • 0.90
% Threonine=% CP x 0.0264 + 0.026; r = 0.94
% Tryptophan = % CP x 0.0087 + 0.037; r = 0.79
Com (N= 153 samples)
% Lysine=% CP x 0.0224 + 0.057; r =0.64
% Methionine=% CP x 0.0192+0.015; r = 0.62
% T.S.A.A. = % CP x 0.0345 + 0.073; r = 0.56
% Threonine= % CP x 0.0336 + 0.014; r = 0.84
% Tryptophan = % CP x 0.0026 + 0.041; r = 0.41
Soybean Meal (N=277 samples)
% Lysine = % CP x 0.0665 + 0.252; r - 0.70
% Methionine=% CP x 0.0 I I + 0.127; r = 0.44
% T.S.A.A. = % CP x 0.0255 + 0.157; r = 0.52
% Threonine=% CP x 0.0344 + 0.203; r = 0.65
% Tryptophan = % CP x 0.0144 + 0.041; r = 0.62
Canola MeaJ (N=57 samples)
% Lysine=% CP x 0.0231 + 1.133; r =0.29
% Methionine = % CP x 0.0157 + 0. I 77; r = 0.67
% T.S.A.A. = % CP x 0.0419 + 0.140; r = 0.60
% Threonine=% CP x 0.0377 + 0.250; r = 0.74
% Tryptophan = % CP x 0.0 l05 + 0.51O; r = 0.51
Triticale (N=26 samples)
% Lysine=% CP x 0.0209 + 0.140; r = 0.88
% Methionine = % CP x 0.0147 + 0.024; r = 0.90
% T.S.A.A. = % CP x 0.0332 + 0.069; r = 0.93
% Threonine=% CP x 0.0264 + 0.047; r = 0.95
These equations can thus be used to adjust
estimated amino acid levels based on the analysed
protein content in the various ingredients. The
crude protein content of ingredients may vary with
cropping conditions, such as heavy fertilization or a
dry growing season and methods ofprocessing.
The equations indicate that the limiting amino acid
concentration does not increase proportionally with
the rise in crude protein. This is because the
proportions ofthe cereal proteins, albumens,
globulins, prolamines and gluteJins, vary with
protein content. For example, the albumens and
globulins arc well balanced proteins, rich in both
lysine and tryptophan. Prolamine protein is a very
poor source of lysine and tryptophan (Table 3-9).
As crude protein content rises, the prolamine protein
tends to increase at a faster rate than albumen and
globulin forms (Figure 3-3). Consequently, the
essential amino acid content of higher protein grain
reflects more the amino acid profile of the prolaminc
25

44. Adapted from Eppendorfer, 1978. J. Sci. Food Agric.
29:995-100 I .
Table 3-1 O. Effect ofIncreasing Total Nitrogen (Crude
Protein) on the Lysine Content ofWheat and Oats.
Wheat Oats
9.4 3.3 4.4
12.5 3.1 4.2
15.6 2.8 4.1
18.8 2.6 4.0
21.9 2.4 3.8
Proportion of Lysine in Total Protein
(Percent ofTotal Amino Acids)
Crude Protein
in Grain
(%)
e
!0
0::
]j
eO AJbumlnaandGlob<II�
��·
protein and less the profile of nutritionally superior
albumens and globulins. Thus. lysine decreases as a
proportion of the total. Oats are an exception to this
rule, since the prolamine protein proportion in oats is
low. The effect ofdifTcring nitrogen contents ofwheat
and oats on lysine content is shown in Table 3-10.
Protein Content
Adapted from Hosenay, R.C. 1986. Principles of Cereal
Science and Technology. American Association of Cereal
Chemists, Inc.
Figure 3-3. Relationship of Protein Content to
Protein Type in Cereal Grains.
Amino Acid Availabilities in Feed
Ingredients
In addition to the total amino acid content in feed
ingredients, the availability ofthese amino acids
should also be considered in practical feed
formulation. Over the last decade, a considerable
amount ofresearch has been conducted that
demonstrates large differences in amino acid
availabilities between various feedstuffs. For
example, the availability of lysine in canola meal is
lower than that in soybean meal. Ifthese
differences are overlooked in a feed formulation
(i.e. diets are formulated based on total rather than
available amino acid levels) then animal
performance will likely be reduced if soybean meal
is replaced by canola meal. However, research at
various institutions, including the Prairie Swine
Centre, has demonstrated that when diets are
formulated based on available amino acid levels in
canola meal and soybean meal. animal performance
can be maintained at high levels even iflarge
quantities ofcanola meal are included in the diet.
Differences in availabilities between feedstuffs
can be attributed to various factors. These factors
include fibre levels, levels ofanti-nutritional factors
that interfere with nutrient digestion and utilization,
protein quality, and heat damage. For example, raw
soybeans contain anti-nutritional factors called
trypsin inhibitors, which reduce the trypsins' effec-
tiveness (trypsins are digestive enzymes produced
Table 3-9. Amino Acid Profile ofVarious Protein Fractions in Corn (g/IOOg of protein).
Amino Acid Albumins and Prolamines Glutelins
Globulins ZeinA Zein B
Arginine 7.35 2.16 3.46 4.49
lsoleucine 4.25 3.53 2.23 3.97
Lysine 4.18 0.46 0.57 4.38
Phenylalanine 3.57 6.11 2.56 5.31
Leucine 6.50 17.49 10.23 12.09
Methionine 1.72 0.94 1.63 2.86
Adapted from: Robuui, J.L., et al., 1974.
26

45. by pigs). When soybeans are processed (oil extrac-
tion or roasting), these trypsin inhibitors will be
inactivated.
Amino acid availabilities are routinely estimated
from apparent ileal digestibilities, i.e., the disap-
pearance (absorption) of amino acids from the
digestive tract prior to the end ofthe small intestine
(terminal ileum). Heal digestibilities are a better
reflection ofamino acid availabilities than
digestibilities measured over the entire digestive
tract because essential amino acids that enter the
large intestine, or cecum. may be altered by resident
bacteria. The bacteria may break down some of
these amino acids, convert them to other amino
acids, or even manufacture new amino acids from
ammonia, thus contributing to an inaccurate digest-
ibility measurement. Essential amino acids that are
digested by bacteria present in the pig's large
intestine and cecum are not available to the animal.
Therefore, to measure the net amounts ofamino
acids extracted from the diet, digesta is collected
before it enters the large intestine. Measuring
amino acids excreted in the feces wilI not reflect
unabsorbed amino acids, but rather unabsorbed
amino acids after possible alteration by the bacteria.
Many nutritionists now formulate diets using ilea!
digestible amino acids rather than total amino acids
in a feedstuff.
Table 3-11 summarizes the estimated apparent
ileal digestibility of amino acids from common feed
ingredients. The word 'apparent' refers to the fact
that the values are not adjusted for what are called
endogenous (internally produced) secretions.
Amino acids consumed in the diet are not the
only amino acids entering the small intestine.
Endogenous secretions, which include sloughed off
intestinal cells, digestive enzymes, and possibly
hormones, are added by the stomach, the salivary
glands, and the small intestine. This process was
described in chapter 2. If these endogenous secre-
tions were constant, apparent digestibilities could be
easily corrected to true digestibilities. However,
that is not the case, and many factors appear to
influence the quantity ofendogenous secretions in
the gut. An important observation is that endog-
enous gut protein losses appear to increase as the
27
protein level in the diet is raised. Because separat-
ing endogenous secretions from those ofdietary
origin is difficult, estimating true amino acid
digestibilities in feedstuffs for swine is not yet
possible.
There is, however, a concern about apparent
amino acid digestibilities in pig feed ingredients
related to these endogenous secretions. More
specifically, the apparent amino acid digestibilities
in a mixture of ingredients many not be the same as
that calculated from the inclusion level ofthe
various ingredients in the diet and their apparent
digestible amino acid contents. This may cause
errors in feed formulation. This concern can be
attributed to the effects ofdietary amino acid levels
(or inclusion levels of the protein source in the test
diet) on observed apparent amino acid digestibilities
(Figure 3-4a). For example, the apparent amino
acid digestibilities in cereal grains, and com in
particular. are generally lower than in protein
sources such as soybean meal. This is because
amino acid digestibilities in cereal grains are deter-
mined at lower levels ofamino acids in the test diet.
This corresponds to low apparent amino acid
digestibilities (Figure 3 - 4a).
Apparent amino acid degestibilities in protein
sources, such as soybean meal and canola meal, are
determined at higher amino acid levels in the test
diet, corresponding to higher apparent amino acid
digestibilities (Figure 3-4a). Ifcorrections are made
for the minimum endogenous gut amino acid losses,
then the corrected "true" amino acid digestibilities
are generally independent ofthe dietary amino acid
level (Figure 3 - 4a). Minimum gut amino acid
losses can be derived from feeding protein free
diets or from regression to zero protein intake when
various diets are fed with varying protein levels
(Figure 3-4b). However, it should be stressed that
the actual endogenous gut amino acid losses are
higher than the minimum losses and they arc
affected by various dietary and animal factors. This
implies that these corrected "true" digestibilities arc
merely a means to improve the precision of diet
formulation; they are not an accurate reflection of
the actual true digestibility ofamino acids in
feedstuffs.

46. Table 3-11. Average Apparent AvailabiUty ofAmino Acids (%) in Common Ingredients.
Ingredient lsoleucine Lysine Methionine Threonine Tryptophan Valine Cystine
Alfalfa Meal 55 47 62 47 54 52 22
Barley 74 68 79 64 68 71 72
Blood Meal 66 84 78 81 80 85 74
Canola Meal 72 74 78 68 64 78 77
Corn 78 65 86 68 64 78 76
Fish Meal 85 86 87 80 76 83 65
(high quality)
Meat & Bone 7l 70 77 66 55 72 54
Meal
Oat Groats 83 79 83 75 80 83 76
Peas 78 83 77 69 67 71 60
SBM (44%) 82 84 85 76 80 79 74
SBM (47%) 83 85 85 78 80 81 78
Sunflower 78 74 87 72 77 75 73
Meal
Triticale 80 73 83 64 70 78 82
Wheat(HRS) 83 72 84 71 79 79 81
Whey 88 81 88 82 82 87 90
Derived from: Centraal Veevoeder Bureau ( 1994 Table of Feeding Values ofAnimal Feed Ingredients); Heartland
Lysine ( 1994 Swine and Poultry Digestibility Tables); BioKyowa ( 199 I Digestible Amino Acids and Digestible Amino
Acids for Swine, BioKyowa Technical Review 2); Rhone Poulenc (1990, first version, Nutrition Guide); Degussa
(Ileal Digestible Amino Acids in feedstuffs for Pigs).
28

47. - 0.4
ic
c, 0.3
�
:§
0.2 1 - "true" dig.
�G)
> 0.10
CJ
Minimum endogenous methionine lossesCl)
a::: 0
0.4 0 0.1 0.2 0 .3 0.4
95 .............. -1 ...... � ...............
.� 90
------·�
'- ---�
., -85 ,,..
/o
:0 / "True"; 80 /Ill
I ApparentCl)
c,
75 .,,
0
TO
0 0.1 0 .2 0 .3
Dietary Methionine (% OM) Dietary Methionine (% in OM)
Figure 3-4a. Figure 3-4b.
Figure 3-4. Relationship between Amino Acid Level in Diet and Observed Apparent and Calculated1 "True"
Ilea! Amino Acid Digestibilities (Figure 3-4a), and the Relationship between Amino Acid Level in Diet and
Observed Recovery at Distal Ileum (Total Endogenous and Non-digested Dietary Amino Acids)(Figure 3-4b).
'According to a review of the literature, it can be estimated that the minimum endogenous gut amino acid losses
(AAend; g/kg dry matter intake) are 0.38 - lysine, 0.10 - methionine, 0.3 l - methionine plus cystine, 0.51 - threonine,
0.18 - tryptophan, and 0.24 - isoleucine. The "true" digestibility (TD,%) can be calculated from observed apparent
digestibilities (AD,%) and the amino acid level in the test diet (AAd, g/kg dry matter) as follows: TD= 100 x (1-
[AAd-{AAd x AD/100} -AAend)/AAd). Note that the slope in the right hand graph represents the true digestibility.
Derived from Fan, M. R. 1994. Methodological considerations for the determination ofamino acid digestibility in
pigs. PhD. Thesis. University ofAlberta.
Ifdiets are formulated based on 'true' rather than
apparent ileal digestible amino acid contents in feed
ingredients, then adjustments may have to be made
to the requirements as well. Requirements ex-
pressed as apparent digestibilities (g/kg ofdiet) can
be converted to those expressed as 'true'
digestibilities, simply by adding the minimum gut
amino acid losses (g/kg ofdiet; g/kg ofdry matter x
dry matter content of the diet/I 00).
Unfortunately (apparent, or true, ileal)
digestibilities do not always provide a good esti-
mate of amino acid availability. The amino acids in
some ingredients are digestible but unavailable
because they are absorbed in a form which renders
them useless to the animal. These amino acids are
excreted, mostly in the urine. This occurrence is a
concern especially for heat treated ingredients of
animal origin - milk products, blood meal, meat
meal, fish meal- but also applies to some ingredi-
ents ofplant origin.
One ofthe unfortunate features ofreduced
availability ofamino acids due to heating is that
lysine is the amino acid most affected. Lysine can
interact with sugars in a chemical reaction called
'carmelization'. This reaction is stimulated by heat
in the presence ofmoisture, the exact conditions
present in the drying process. Carmelization, as its
name suggests, is associated with a colour change in
the grain or protein. Thus, darkened grains or
protein supplements tend to be down-graded for
livestock due to concerns about carrnelization and
associated changes in lysine availability. At present,
there is no assay available that will allow us to
routinely evaluate this chemical (un)availability.
Amino Acid Requirements
Clearly, dietary protein is very critical to the
pig. None of the body processes described above
could occur without the necessary proteins being
present. Consequently, inadequate amino acid
intake from the diet resulting in impaired protein
29

48. Deficient Diet
Deficient 01e1
ESSENTIAL AMINO ACIDS
llSSENTIAL AMlNO ACIDS
The explanation above brings up the concept
of the 'first limiting' amino acid. In Figure 3-5,
lysine would be the first limiting amino acid in the
deficient diet because the amount present is lower,
relative to requirement, than any other amino acid.
Methionine would be considered second limiting.
There are no third limiting amino acids in this
example. Lysine is the amino acid discussed most
often because in practical diets for swine, it is the
one most likely to be first limiting. Thus,
nutritionists pay particular attention to lysine.
Remember, however, that while adding extra lysine
to a deficient diet will be beneficial, you must also
consider the supply ofother limiting amino acids if
the diet is to be fully balanced.
The balance in which amino acids are required by
pigs can be determined in a number ofways. Until
recently, the most common approach was to study
individual amino acids and determine the require-
ment ofeach one in terms of maximum growth rate
or carcass quality. A second approach, gaining in
popularity, is to relate the requirement for all amino
acids to one reference amino acid, often lysine.
This approach emphasizes the concept ofamino
acid balance and integrates the requirement for all
10 essential and two semi-essential amino acids.
For example, the requirement for lysine is defined
in absolute terms (e.g., 1.3% in a starter diet). The
requirement for the other amino acids is then
established relative to lysine.
Table 3-12 provides an estimate for the optimum
amino acid balance, also referred to as the ideal
dietary protein. Lysine is set at l 00 and all other
amino acids are defined relative to I 00. For exam-
ple, the amount oftryptophan in a diet should be
about 19% of lysine, while threonine should be
65% of lysine. Thus. in a diet containing 0.85%
lysine. there should be at least 0.16% tryptophan
and 0.55% threonine. Remember that the balance
in which amino acids arc required by pigs will vary
somewhat with body weight, (lean) growth rate,
level ofmilk production, and diet composition. For
example, as pigs grow heavier relatively more
protein is required for body maintenance functions.
Because proteins required for body maintenance
functions contain large quantities ofthreonine and
T.S.A.A. relative to lysine, requirements for
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Figure 3-5. Diagram Illustrating What is Meant by
the Term Amino Acid Balance as it Relates to Evalu-
ating Swine Diets.
100
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The importance of a proper balance ofamino
acids is illustrated in Figure 3-5. Tn the adequate
diet, all amino acids arc present at 100% of
requirement. Thus, when the body requires amino
acids for protein synthesis, each will be present in
sufficient quantity. In the inadequate diet, both
lysine and methionine are present at levels well
below requirement. Iflysine is present at 50% of
the requirement, it will place this upper limit on the
rate of protein synthesis. Not only will body
functions be impaired, but other amino acids
supplied in adequate quantity will be wasted.
synthesis has a profound effect on a pig's health and
productivity. That amino acids present in the diet
are balanced according to the pig's need is very
important. Ifall other amino acids are present in
quantities well above requirement, but lysine is
missing or inadequate, the pig will still be unable to
grow to its full potential because it must have all
amino acids present in adequate quantities. Each
individual protein is created by a specific sequence
ofamino acids; the lack ofany single amino acid
can prevent formation of the total protein.
30

49. Amino acid
Lysine
Threonine
Methionine
Methionine plus cystine
(T.S.A.A.)
Tryptophan
Isoleucine
Leucine
Phenylalanine
Phenylalanine+ tyrosine
Valine
Histidine
Arginine
Suggested balance
100
60-70
30
56-64
18-20
60
100
60
100
70
30
45
31
However, minerals have other important functions
to fulfill ifthe pig is to perform well. Many
enzymes will not function unless certain minerals
are present. Muscles could not contract and nerves
could not send signals in the absence of minerals.
Minerals can be assayed directly in feedstuffs
with great accuracy and precision. Samples are first
ashed using very high temperatures (550°C) or
strong acids to remove all but the mineral content.
This residual material is then dissolved in weak acid
and assayed by various methods.
Minerals can be divided into two types:
macrominerals and microminerals (Table 3-13).
They are differentiated solely by the relative
amounts present in the diet. Macrominerals are
present in greater concentration and are therefore
measured in terms ofpercent or grams per kilogram
(1 g/kg equals 0.1%). Microminerals are present in
much smaller quantities and are measured in terms
of parts per million or milligrams per kilogram ( 1
ppm equals I mg/kg). Thus, the concentration of
rnicrominerals in the diet is about one-tenth to one-
ten thousandth that ofthe macrominerals. To put
ppm and percent in perspective: 1 ppm is I second
out of 11 .5 days; 1 percent is approximately one
second out of 1.5 minutes.
The quantity ofeach mineral present in a pig's
body reflects, in a general way, the amount required
in the diet. Table 3-13 shows the approximate
concentration ofminerals in the animal body. Note
that calcium and phosphorus are present in by far
the highest concentration, while minerals such as
selenium and chromium can be found only in trace
amounts. Calcium and phosphorus are involved in
the skeleton and are thus present in large quantities,
while selenium supports the activity ofcertain
enzymes, a role which requires only trace amounts.
Importance should not be equated with quantity; a
deficiency of a micromineral can be just as serious
as that ofa macrornineral.
Table 3-12. Suggested Optimum Amino Acid
Balance in Protein {Ideal Protein) for Swine.
Minerals
Minerals are an important constituent ofthe pig's
diet. As a group, they perform far more functions
in the body than they are normally given credit for.
We tend to associate minerals, such as calcium and
phosphorus, with the hard structures ofthe body
because oftheir involvement with bones and teeth.
threonine and T.S.A.A., expressed as a proportion
of lysine, will increase as pigs grow heavier. In a
similar fashion, requirements for threonine and
T.S.A.A., relative to lysine, will reduce as lean
growth rates in pigs continue to increase. The
concept of ideal protein, the optimum balance in
which amino acids are required by pigs, has proven
very useful in practical swine diet formulation. This
concept a11ows for a rapid estimation of require-
ments for essential and semi-essential amino acids
once the requirements for one amino acid have been
established. Determining the optimum amino acid
balance for different groups ofpigs under varying
conditions remains an important area in swine
nutrition research. Refer to the specific chapters on
feeding various classes ofswine for further infor-
mation on amino acid requirements and optimum
dietary amino acid balances.

50. Table 3-13. Approximate Mineral Composition of the
Animal Body.
Macrominerals Microrninerals
Element % Element ppm
Calcium l.50 Iron 20-80
Phosphorus l.00 Zinc 10-50
Potassium 0.20 Copper 1-5
Sodium 0. 16 Manganese 0.20-0.50
Chlorine 0.11 Iodine 0.3-0.6
Sulphur 0.15 Molybdenum 1-4
Selenium 1.7
Chromium 0.08
Adapted from: McDonald, et al. 1973.
Macrominerals
Calcium
Most ofthe body's calcium is present in bones.
Bone ash contains about 36% calcium and 17%
phosphorus. Calcium deficiencies lead to leg
weakness, lameness, and in extreme cases, bone
fractures. Bone is a strong and dynamic tissue. It is
dynamic in that calcium and phosphorus in the bone
are constantly being exchanged for calcium and
phosphorus in the blood. Since bone is rigid and
strong, many people think bones are not alive.
That, clearly, is not true!
The fact that so much of the body calcium is
present in bone often leads people to ignore its
other very important functions. For example,
calcium is required for blood to clot and for muscle
and nerve function. Calcium helps regulate the
acid-base status of blood and is involved in regulat-
ing cell division and hormone secretion. Because of
its important role in muscle contraction, calcium
deficiency can lead to cramping and even tctany.
Basal ingredients in most diets are poor sources
ofcalcium. For example, cereal grains contain less
than 0.05% calcium and vegetable protein
supplements also contain only small quantities.
Meat meal is an excellent source of both calcium
and phosphorus but due to its variability, must be
formulated into the diet with caution. Fortunately,
an inexpensive source of calcium, limestone (38%
calcium), is available for diets.
Although limestone is not expensive, supple-
menting large quantities ofcalcium 'costs' a consid-
erable amount in terms ofthe total diet because
limestone dilutes all other nutrients. Although
calcium is added to the diet at least expense by
using limestone, limestone contains no energy or
protein, so adding it in place of barley or com or
any other basal grain will reduce the diet's energy
and amino acid content unless other adjustments are
made. To provide a rough estimate of the true cost
ofadditional calcium in a diet, multiply the cost of
limestone required to meet the new levels by
approximately 2 or 3. This equation accounts for
the cost ofovercoming nutrient dilution by lime-
stone as well as the cost ofadding the calcium
itself.
Take care to avoid too much dietary calcium
because it can lead to depressed feed intake. This
situation appears a greater problem in starter diets
and lactation rations than at any other time because
in both cases, feed intake is a major concern, and
these diets tend to be formulated to contain high
levels ofcalcium to meet the pig's nutrient
requirements. Although the exact limit for calciwn
has not been defined, levels in excess of 1.25%
should be avoided. This level poses no hardship,
since no diet needs to contain more than about
1.20% calcium, and most diets are quite adequate at
0.90% or lower.
Phosphorus
Phosphorus, along with calcium, is a major bone
component. More phosphorus, however, is present
outside the bones than is the case with calcium.
While about 99% ofbody calcium is present in
bones and teeth, only about 80-85% of the phos-
phorus is present in these tissues. The metabolism
ofcarbohydrates, fats, and amino acids all require
phosphorus. Phosphorus performs numerous other
functions, including being a major part of the
'energy currency' in the body. This chapter has
already discussed how the body is able to break
down food materials and convert it into energy
forms. Certain compounds in the body wbich
contain phosphorus (ATP, creatine phosphate) trap
this energy and transport it to the site ofuse in the
cell. In the same way that money allows us to earn
cash in one location at one time and spend it at a
different location at a later time, phosphorus allows
32

51. Table 3-14. Total Phosphorus Content and Phospho-
rus Availability of Some Common Ingredients.
Derived from NRC, 1988 and table of feeding values of
Animal Feed Ingredients (Centraal Veevoeder Bureau)
The Netherlands.
the body to generate energy in one location for later
use in a different part ofthe cell. Although none of
this activity requires large amounts, phosphorus is
nonetheless important to keep the body functioning
properly.
Whereas phytate is an undesired component of
swine diets, it plays a very important role for
growing plants that need it to store phosphorus for
later use. Late application offertilizer may increase
total phosphorus in the seed but much of the addi-
tional mineral is in the form ofphytate and less
available to the pig when it eats the plant.
Phosphorus Calcium Sodium
(%)
Source
Bone meal 12.0 24.0
Defluorinated
phosphate 18.0 31.0 4.0
Diammonium
phosphate 20.0 trace
Dicalcium
phosphate 18.0 21.0
Monocalcium
phosphate 22.0 16.0
Given the low availability ofphosphorus in most
swine feed ingredients, the cost ofphosphorus, and
the contribution ofphosphorus excreted with swine
manure to environmental pollution in areas with
extensive swine operations, there is much interest in
enhancing the efficiency with which dietary phos-
phorus is utilized by pigs. A means to accomplish
this is to add enzymes, called phytases, to the pig's
diet. Various studies have shown that these en-
zymes enhance the availability ofphytate phospho-
rus in pig feed ingredients. This reduces the need
for inorganic phosphorus in pig diets. Concerns
with the use ofthese phytases include cost and
product stability. Phytases are generally unstable at
higher temperatures which is a concern when feeds
are pelleted. It should be noted that some ingredi-
ents such as wheat and triticale contain some
endogenous phytases.
Note: Actual nutrient composition may vary depending
on the supplier. Nutrient composition should be con-
firmedby chemical analysis.
Table 3-15. Feed Grade Phosphate Sources.
calcium costs about forty cents per tonne while
0.1% additional phosphorus costs two dollars. As
with calcium, part of this cost is associated with the
cost of the phosphorus itselfand part is overcoming
the diluting effect ofthe added phosphorus source.
Commonly used sources ofsupplemental phosphate
are shown in Table 3-15.
Total Phosphorus
Phosphorus (%) Bio-availability(%)
A major concern with respect to dietary phospho-
nis levels is the proportion the pig actually utilizes.
A part of the phosphorus supplied by cereaJ grains
and vegetable proteins is bound to phytate and is
much less available than in other forms. Table 3-14
shows the amount oftotal phosphorus present in
common ingredients and an estimate ofphosphorus
availability.
Ingredient
Corn,dry 0.25 15
Corn,
high moisture 0.25 49
Barley 0.29 31
Wheat 0.34 50
Oats 0.31 30
SBM, 47% 0.60 25
Canolameal 1.07 21
Peas I.OJ 47
Wheat
middlings 0.95 45
Wheat bran 1.10 35
Meat and
bone meal 4.75 68
Phosphorus is a much more expensive ingredient
than calcium, so maximizing utilization should be a
priority. Presently, the addition of 0.1 % additional
The ratio ofcalcium to phosphorus, and more
accurately, available phosphorus, in the diet should
also be considered. Dietary calcium to phosphorus
33

52. levels of 3: I and 1.25: I for available and total
phosphorus, respectively, are thought to optimize
calcium and phosphorus utilization. The impor-
tance of the ratio appears to be greater ifcalcium is
present at or slightly above requirement. In practi-
cal diets the ratio of calcium to available phospho-
rus in the diet should be maintained at 2.7 to 3.4.
This corresponds with calcium to total phosphorus
rations of approximately 1.1 to 1.5. If the diet
contains plenty ofcalcium and phosphorus, the ratio
becomes much less important. A deficiency in
vitamin D also impairs the utilization ofcalcium in
the diet.
Sodium
Sodium, together with potassium and chloride, is
required by the body to maintain proper water
balance and to help generate the electrical charges
needed by muscles and nerve tissue to function
normally. Sodium is particularly important in the
body's many transport processes. Absorption of
amino acids, sugars. many minerals, and water from
the gut could not occur without sodium.
Sodium is often considered to be 'salt' since
table salt is actually sodium chloride and contains
about 39% sodium. This explanation may be a
convenient one but is not physiologically or even
nutritionally appropriate. Sodium and chloride are
quite distinct chemicals and should be considered as
distinct entities. They are required independently in
a pig's diet.
The most obvious symptom of sodium deficiency
is a depressed appetite. Excess sodium can result in
diarrhea. Since many diseases also cause diarrhea,
observing only this symptom is not a very effective
way to diagnose salt excesses in the diet! Although
pigs may become loose ifexcess salt is present in
the feed, they can tolerate very high levels without
loss of performance if they have access to plenty of
clean water. Ifaccess to water is restricted, pigs
receiving excess salt in their diet can die. Since
automatic waterers can become plugged and there is
no beneficial effect ofextra salt in a diet, restrict
added salt to no more than 0.5% of the diet.
Basal ingredients are poor sources ofsodium. For
example, cereal grains generally contain less than
34
0.05% sodium (compared with a requirement of
0.10%). Vegetable-based protein ingredients are
much richer in sodium, containing 0.30 - 0.50%. A
good, economical source of sodium is common salt
(39% sodium). Feed companies sell four types of
salt defined according to colour. White salt con-
tains only NaCl, red salt contains iodine, blue salt
contains iodine and cobalt, and brown salt contains
trace minerals. For most swine diets, salt will be
added as part of the premix or supplement. If the
premix contains other sources of iodine or trace
minerals, only pure (i.e., white) salt should be
added to the diet.
As mentioned above, most swine diets contain
0.30 to 0.50% added salt to ensure the sodium
requirement is met. Ifyou wish to add sodium
without chloride, sodium bicarbonate is a reason-
able choice. Sodium bicarbonate contains about
27% sodium and is available in feed grade forms.
Meat meal, fish meal, and milk products often
contain considerable quantities ofsodium but since
they are highly variable, be extremely careful in
depending on these ingredients to supply the total
sodium requirement.
Drinking water from deep wells sometimes
contains considerable quantities ofsodium plus
other salts. In this case, sodium is often removed
from the diet to help alleviate scouring associated
with poor quality drinking water. This practice may
or may not help pigs adapt to bad water. Take great
care to avoid a sodium or chloride deficiency if
removing dietary salt. Ifyou suspect water quality
problems, request a detailed water analysis that
includes both sodium and chloride. By estimating
water intake (assume 2 kg ofwater are consumed
per kg of feed), you can determine the daily intake
ofboth sodium and chloride. If the pig's require-
ment for both sodium and chloride is not met by
that in the water (it rarely is), at least some salt must
be added to the feed. Consult a qualified nutrition-
ist to calculate the minimum amount ofsalt re-
quired.
Remember that water quality can change over
time. lffeed salt is reduced, ongoing analysis ofthe
water is required to ensure that sodium and chloride
intake is maintained. Interestingly, if removing salt

53. from feed has reduced the scouring associated with
poor-quality water, a chloride deficiency (which
results in reduced feed intake, thus reduced scour-
ing), is likely to have developed. A pig's perform-
ance will suffer more as a consequence ofthe
chloride deficiency than it would have due to the
water quality problem.
Salt analysis ofa diet is determined by measuring
either sodium or chloride and adjusting it to reflect
total salt. Table 3-16 provides information for
conversion ofsodium, chloride, and salt values.
Table 3-16. Calculating 'Salt' Values from Sodium or
Chloride Assays in Swine Diets
Salt Sodium Chloride
(%)
0.1 0.04 0.06
0.2 0.08 0.12
0.3 0.12 0.18
0.4 0.16 0.24
0.5 0.20 0.31
0.6 0.23 0.37
0.7 0.27 0.43
0.8 0.31 0.49
0.9 0.35 0.55
1.0 0.39 0.61
To determine a diet's 'salt' content, locate the
appropriate sodiwn or chloride value from the
chemical analyses and identify the salt content on
the same line. For example. ifan analysis revealed
a sodium content of0.20%, tbe diet contains 0.5%
salt. The table can also be used to determine the
amount of sodium and chloride present ifthe
amount of salt is known. This approach makes one
important assumption - that sodium and chloride
are being supplied largely by salt. ln most diets,
this assumption is true.
It is important to note, however, that other dietary
components which supply chloride or sodium alone
may make this table invalid. For example, some
diets contain considerable amounts ofcholine
chloride, a source of the vitamin choline. Some
diets, notably pig starters, will contain lysine
hydrochloride, a source ofthe amino acid lysine.
Both chloride sources could bias the salt value if
chloride is used to estimate salt content. Thus, ifa
diet is found to contain excessive 'salt', be sure to
consider the method ofanalysis before worrying
about a possible formulation or mixing error.
Consult a nutritionist ifyou suspect a problem.
Chloride
Chloride, like sodium and potassium, plays a
major role in water and acid-base balance. Ifow-
ever, it also performs a number of independent
functions, including the formation ofacid to sup-
port digestion in the pig's stomach.
Chloride is often supplied in the diet as part of
table salt, which is sodium chloride. The nutrition-
ist considers sodium and chloride as independent
components ofa diet. A diet can be quite adequate
in sodium and be deficient in chloride because they
are supplied in different proportions by the basal
ingredients. Standard practice now includes 0.30 to
0.50% salt in the swine diet formula. This practice
will provide 0.18 to 0.30% chloride, sufficient to
meet the pig's requirement of about 0.15%.
A pig can handle large quantities ofexcess ch1o-
ride in the diet, provided it has a consistent supply
offresh drinking water available. A pig's kidneys
are very efficient in excreting excess sodium and
chloride.
Chloride can be added to swine diets independent
ofsodium by removing the salt and replacing
calcium carbonate (limestone) with calcium chlo-
ride. Calcium carbonate contains about 38%
calcium; calcium chloride, in the anhydrous form,
contains about 36% calcium and 64% chloride.
Hydrated forms, that is those forms in which water
is chemically bound to the mineral, contain less
calcium and chloride. Chloride can also be added
as potassium chloride (47% chloride) or ammonium
chloride (66% chloride).
Some ground water contains excessive levels of
sodium, which causes scouring and poor pig per-
formance. In an attempt to minimize the effect of
excess sodium in the water, salt, containing sodium
chloride, is removed from the feed. Although this
35

54. action may provide some relief, a chloride defi-
ciency may result since water rarely contains much
chloride. Therefore, even partial removal ofdietary
salt requires some care; consult a qualified nutri-
tionist since a deficiency in chloride will depress
feed intake and slow growth rate.
Magnesium
About two-thirds ofthe total magnesium in the
body is found in bone. Magnesium is important in
stimulating the activity of many enzymes that
catalyse chemical reactions in the body. It is also
required for normal nerve and muscle function, and
for fat and protein utilization.
Like potassium, common feed ingredients supply
sufficient magnesium to meet the pig's normal
requirements. For example, a cereal grain-based
diet will contain about 0.1% magnesium, more than
twice the pig's requirement. Ifmagnesium must be
supplemented, magnesium oxide (51-59%
magnesium) can be used.
Potassium
Potassium is an important mineral. It helps to
maintain both water and acid-base balance, supports
the transport ofnutrients across cell membranes,
and is involved in maintaining heart rate.
Potassium tends to be overlooked in nutrition
because natural ingredients supply more than
enough of it to meet a pig's requirement. Common
protein supplements, such as soybean or canola
meals, are particularly good sources ofpotassium.
For this reason, combined with the fact that cereal
grains often supply all the potassium the pig
requires, a potassium deficiency is not usually a
concern in practical diets.
Excess potassium may depress the absorption of
many nutrients from the intestinal tract but this
situation appears to require dietary levels in the
range of2.0% (practical diets contain less than 1%
potassium) combined with a wide
potassium:sodium ratio.
Potassium rarely needs to be supplemented to
healthy swine, but if it docs, potassium bicarbonate
36
(38.0% potassium) and potassium chloride (50.5%
potassium) are logical choices.
Sulphur
Most of the sulphur present in a pig's body is
found in the amino acids, methionine and cystine.
Practical diets are never deficient in sulphurper se
and supplementing a diet with pure sulphur is not
required. However, the sulphur amino acids need to
be added via the protein supplement to meet the
pig's requirements. (see Amino Acids)
Microminerals
The microminerals required in a pig's diet are
discussed in the following sections. Some
microminerals are present in sufficient quantity in
basal ingredients and are not normally
supplemented. Others are routinely supplemented
to prevent deficiency symptoms. Table 3-17
summarizes the information on the microminerals
including those which are normally supplemented in
practical diets, maximum tolerable limits for the
pig, and common supplemental sources.
Cobalt
Although there is some evidence that cobalt may
be involved in several bodily functions, cobalt's
major role is as a constituent of vitamin B12
• A pig's
requirement for cobalt is very low; ifvitamin 812
is
properly supplemented, there is no need to add
additional cobalt to swine diets.
Copper
Copper is essential for formation of red blood
cells. A copper deficiency may lead to anemia, a
type very different from that caused by an iron or
vitamin B12
deficiency. Copper plays an important
role in certain enzyme systems, most importantly
those involved in energy metabolism. Finally,
copper is required for normal hair pigmentation.
Although a copper deficiency is very rare in
swine, copper is always supplemented in a pig's
diet. Normally, only 6-12 ppm is required. Usually
this amount is supplied by copper oxide (75%
copper) or copper sulphate (25% copper), the latter
being the more available source ofcopper. Metallic
copper is poorly absorbed so is not used in diets.

55. Table 3-17. Maximum Tolerable Limits and Supplemental Sources of the Microminerals.
Mineral Supplemented Suggested Upper Source
Limit, mg/kg'f Name Micromincral Content3
Copper Yes 250 (125)4
Copper sulphate 25%
Copper oxide 75%
Cobalt No 10
Iodine Yes 400 Calcium iodate 63.5%
Potassium iodide 76.0%
E.D.D.I. 79.5%
Iron Yes 3000 Ferrous sulphate 20.0-32.0%
Ferrous carbonate 36.0-40.0%
Ferrous fumarate 32.0%
Manganese Yes 400 Manganous oxide 55.0-65.0%
Manganous sulphate 27.0-28.0%
Selenium Yes 2 (0.3)4
Sodium selenate 40.0%
Sodium selenite 45.0%
Zinc Yes 1000 Zinc oxide 70.0-80.0%
Zinc sulphate 36.0%
I As recommended by National Research Council 1980.
2Upper limits based on nutritional toxicity. These limits may differ from those contained in the Feeds Regulation 1983.
3Exact concentration may vary depending on the source. Actual nutrient composition should be determined by
analysis.
"Legal upper limit according to the Canadian feeds Act (see chapter I I).
Copper sulphate, also called 'bluestone' because
of its blue colour, was a popular disinfectant in the
days before more powerful and effective agents
were discovered. For example, copper sulphate was
used in foot baths to treat lame animals.
Copper is now added to swine diets in high levels
to act as an inexpensive growth promotant. It is a
more effective growth promotant in diets for starter
and grower pigs than for finishing pigs. Adding up
to 125 ppm copper (from copper sulphate) to feed
is legally permitted in Canada. This amount is well
above the amount required for nutritional purposes
but costs less than one dollar per tonne.
Adding copper sulphate to a diet at growth
promoting levels will produce black sticky feces in
pigs. Also, in regions of high livestock density, the
use ofcopper as a growth promotant has sparked
criticism due to the potential accumulation of
copper in the soil. Although swine can tolerate
copper levels in excess of250 ppm, sheep have
been found to be highly susceptible to copper
toxicity. Total dietary copper levels for sheep
should not exceed 25 ppm. Consequently, swine
diets containing copper at growth promotant levels
must not be fed to sheep.
37

56. Chromium
Until recently, chromium was not considered an
essential nutrient for swine. Recently, however,
considerable interest has been generated in the
effect ofchromium and chromium-containing feed
additives on the performance ofgrowing-finishing
pigs and sows. Chromium, via its involvement with
the so-called glucose tolerance factor. may be
required for the utilization of large amounts of
sugars. There are also some indications that chro-
mium may improve the animal's immune status and
increase the effectiveness of insulin. Insulin,
produced by the pig, is an important hormone that
is required for energy and amino acid utilization.
Several studies have demonstrated that including
inorganic chromium in practical swine diets does
not affect animal performance. Other studies have
shown that adding certain chromium-containing
compounds, such as chromium picolinate, to
finishing pig diets improves animal performance,
especially the lean yield in the carcass and
reproductive performance in sows. Further research
is required to determine the optimum level of
chromium and the form in which it should be
included in pig diets and the conditions under which
it is most effective.
Iodine
Iodine's main role in the body is as part of the
hormone, thyroxine. Thyroxine, produced by the
thyroid gland, is involved in regulating a pig's
overall metabolic rate. An iodine deficiency,
resulting in impaired thyroid function, will have a
serious effect on swine growth and productivity.
Iodine deficiency leads to a condition known as
goiter, which refers to an enlargement ofthe thyroid
gland. Goiter can be observed as a swelling in the
neck where the thyroid gland is located. Goiter
causes reproductive failure or the birth of weak or
dead, hairless piglets.
Goiter is not caused only by a dietary deficiency
of iodine. Certain ingredients in the diet impair
iodine utilization by the thyroid gland. The highly
successful rapeseed breeding program, which
resulted in the development of canola, was in part
motivated by a need to remove glucosinolates, well-
38
known goitrogenic compounds in rapeseed meal.
Canola meal, with very low levels of glucosinolates,
can be used in swine diets (including those of
breeding animals) without fear of impairing thyroid
function.
Primary iodine deficiency is prevented by includ-
ing iodine in the mineral premix. Various forms of
iodine can be used including potassium iodide
(68.5% iodine), calcium iodate (63.5% iodine), or
EDDI (ethylene diamine dihydro-iodide; 79.5%
iodine). Adding iodized salt (0.007% iodine) at the
rate of2 kg per tonne of feed provides sufficient
iodine to meet the pig's requirement. Feeds of
marine origin, such as fish meals, are also rich
sources of iodine.
Iron
Iron, a component ofhemoglobin in the blood, is
required to help the blood transport oxygen from
the lungs to the body tissues. An iron deficiency
can be very serious because the oxygen-carrying
capacity ofthe blood is impaired. lron is also a
constituent ofmany important enzymes throughout
the body. Symptoms ofdeficiency include poor
vigour, lethargy. and a pale, white skin colour.
Iron is always supplemented in pig diets, although
pigs would probably do quite well without it. A
pig's requirement for iron is not very high and its
body has the ability to retain iron very well, espe-
cially ifdietary sources are scarce. Furthermore, as
the need for iron rises, so does the ability ofthe
pig's gut to extract iron from the diet. If market
pigs or sows appear iron deficient, the cause is more
likely a bleeding ulcer, or other illness, than a
dietary deficiency. However, iron is very inexpen-
sive and is added to the diet as cheap insurance.
A definite exception to the pig's limited need for
iron is the neonatal pig. NeonataJ pigs grow very
rapidly and require a great deal of iron to support
this growth. Sow's milk is a poor source of iron so
supplements are imperative. Injectable iron in a
single dose of approximately 150 mg should be
administered no later than 3 days ofage. A second
injection may be given at approximately 21 days
(see Chapter 7).

57. [fan iron injection causes sudden mortality, the
little pigs are possibly suffering from a vitamin E
and/or selenium deficiency. Ifthis is the case, the
solution is to treat the sow herd with either inject-
able vitamin E/selenium or increase the quantities of
each element present in the diet.
An iron deficiency leads to anemia, which in turn
causes stunted growth and reduced disease resist-
ance. Some producers have seen almost 'magical'
recovery from scours in pigs 2 to 4 weeks of age
merely by providing iron that was deficient earlier
in the pig's life. Avoid extreme excesses, however
- some research suggests that too much iron may
actually predispose young pigs to diarrhea.
Iron should be injected in the neck rather than the
ham muscle. The neck location avoids the possibil-
ity ofstaining expensive cuts (e.g., the ham) and
making the product undesirable to the consumer.
Ferrous sulphate (20 - 32% iron) is the first
choice of iron supplement in a diet. A less desir-
able second choice is ferrous carbonate (36 - 45%
iron); iron oxide is nothing more than rust and is of
little nutritional value. Iron oxide may appear on
some feed labels because it is used as a colouring
agent to ensure a uniform red colour. This practice
is most common in mineral supplements or
premixes. Pigs eating such diets produce red
manure due to iron oxide's poor digestibility.
Manganese
Manganese acts as an important enzyme activator
so is critical for normal utilization ofcarbohydrate,
fat, and protein in a pig's diet. Lameness is a
symptom ofdeficiency because manganese is
involved in bone formation. Manganese deficiency
can also impair normal reproductive performance.
causing such problems as irregular estrus cycles,
late sexual maturity, and weak piglets at birth.
Supplements are required because basal dietary
ingredients cannot be relied on to supply sufficient
manganese. Manganese is routinely added to the
mineral premix, usually as manganous oxide (55 -
65% manganese) or manganese sulphate (27 - 28%
manganese), so a manganese deficiency in swine is
very rare.
Selenium
The history ofselenium as a nutrient is an inter-
esting study. Initially selenium was considered only
as a toxic substance, responsible for alkali disease
and blind staggers in cattle. More recently nutri-
tionists have learned that animals must have sele-
nium in their diet. Selenium helps the body protect
against the breakdown ofcell membranes. It works
with vitamin E in this regard, so the two elements
are often discussed together.
Because selenium was first identified as a toxic
substance and more recently has been found to
cause cancer, government agencies are very con-
servative in allowing selenium supplementation of
livestock feeds. ln Canada, 0.3 ppm can be added
to diets for all classes of swine. Supplemented with
adequate vitamin E, this amount would appear to be
adequate under most circumstances. Nonetheless,
reports of selenium deficiency persist, especially in
areas where the soil is low in selenium, thus a low
natural supply in the grain. Adding more than 0.3
ppm ofselenium to a diet requires a veterinary
prescription.
Selenium deficiency in pigs result in mulberry
heart disease and liver necrosis. But, before adding
selenium to a diet in response to a problem with
mulberry heart disease, review the situation
carefully. Ifthe problem is occurring in recently
weaned pigs, supplementation ofthe starter diet
may be of limited value because the piglets will eat
very little before succumbing to the disease. In this
case. increasing the vitamin E content ofthe nursing
sow diet or injecting pregnant sows with injectable
vitamin E-selenium is the preferred course of
action. Some additional attention to the diagnosis
ofmulberry heart disease is also advised; infections
ofStrep. Suis Type II have been suggested as a
plausible alternative diagnosis. Discuss your
situation with a qualified nutritionist and/or veteri-
nary pathologist before beginning any treatment.
Concerns about selenium toxicity must not be
underestimated because the difference between
required and toxic levels is so small. While the
requirement is in the range of0.1 to 0.3 ppm, only
7.0 ppm (25 times the requirement), is toxic.
39

58. Selenium supplements in the diet are provided by
sodium selenite (45% selenium) or sodium selenate
(40% selenium). Because selenium is required in
such small amounts, 0.7 gm ofsodium selenite per
tonne will supply 0.3 ppm. Many feed companies
use diluted selenium sources to ensure proper
distribution in the mix and to avoid the risk of
toxicity. In some instances, selenium can be admin-
istered by injection, often as a combination of
vitamin E and selenium, to deal quickly with
suspected problems.
Zinc
Zinc is an important component in a pig's diet.
Zinc is a constituent of many enzymes and acts as a
co-factor of others. It is also a part of the hormone,
insulin.
Zinc deficiency in the pig results in poor overall
growth, reduced appetite, and poor hair growth. A
specific syndrome in swine, known as parakeratosis,
is the result ofa zinc deficiency. It shows up as skin
lesions which may open and later develop scabs.
Parakeratosis is associated with poor growth rate
and impaired feed efficiency.
The utilization ofzinc can be impaired by exces-
sive calcium in the diet. Indeed, dietary calcium has
a profound effect on zinc requirements. At recom-
mended calcium intakes, 50 ppm zinc appears to be
quite adequate; excessive calcium can more than
double the amount ofzinc required to prevent
deficiency symptoms. Phytic acid. common in
cereal grains and protein supplements ofplant
origin, also reduces the pig's utilization ofzinc.
Zinc should always be supplemented in a swine
diet. Consequently, it is included in the mineral
premix as zinc oxide (70-80% zinc) or zinc sulphate
(36% zinc). As zinc supplied in the form ofa
sulphate is more available to the pig than zinc
supplied in the form of an oxide. zinc sulphate is
preferred over zinc oxide.
Recent studies have shown that including ex-
tremely high levels of zinc oxide (up to 3000 ppm
ofzinc) in dicts for newly weaned piglets increased
feed intake and growth rate. It is speculated that at
these pharmacological levels, zinc is effective in
controlling£. coli scours. However, these levels
are higher than is allowed in swine feeds in Canada.
In addition, if these high zinc levels arc fed for too
long. e.g., more than two to three weeks, they may
result in zinc toxicosis. Alternative means to
control the negative effects of£. coli scours are
preferred.
Vitamins
Vitamins are one ofthe six major nutrient classes
in a diet. The other classes are energy, protein,
minerals, essential fatty acids, and water. A pig
requires vitamins to support or stimulate the many
chemical reactions that occur in the body as part of
normal metabolism. Although they are present in
small quantities, vitamins perform very important
functions. As is the case with all nutrients, the
quantity present is not an indicator of importance.
Vitamins can be analysed but the cost is high. Also,
once they are added into a mixed feed, the levels may
be too low to be accurately analysed. It is rare to test
for vitamins unless a problem arises. Many feed
manufacturers test for one or two vitamins, e.g., ribo-
flavin and vitamin A, in spot samples to ensureproper
formulation and mixing ofpremixes.
Deficiencies of a vitamin or group of vitamins
must be avoided to maximize swine performance.
Unfortunately, the role ofvitamins in nutrition has
often been misunderstood; vitamins have in many
cases been viewed in almost the same way as drugs.
For example, vitamin X will prevent spraddle leg or
vitamin Y will improve estrous behaviour. Al-
though individual vitamins have specific functions
and a deficiency will result in certain symptoms,
this does not mean that adding additional quantities
ofa vitamin or vitamins will improve health or
performance. As always, the essence of nutrition
must be to balance all nutrients according to need
and not to assume that one nutrient possesses
magical qualities.
At least some vitamins arc naturally present in the
diet and need not be supplemented. Others are
present, but are either poorly available (niacin) or
arc in amounts well below the requirement (vitamin
E) so that supplementation is necessary. Some
vitamms, such as vitamin C (ascorbic acid), are
40

59. synthesized by the pig. Others, such as biotin, are
produced by the microbes present in the lower gut.
Under some conditions, natural synthesis may be
impaired, resulting in greater need for supplementa-
tion. For example, sulpha drugs in the feed or water
may reduce or even eliminate biotin synthesis in the
gut. All vitamins can be produced chemically so
that supplementation, when necessary, is not a
problem other than cost. Overall, vitamin fortifica-
tion generally represents less than 4% ofthe total
feed cost.
Identifying vitamin deficiencies is not a simple
task because the symptoms are rarely specific. For
example, a niacin deficiency impairs appetite and
growth rate, and causes severe diarrhea. Many
other factors can produce the same symptoms.
Consequently, symptoms must be considered in the
context of other information, such as feed analysis,
herd history, and a thorough review ofhealth status,
to ensure an accurate vitamin deficiency diagnosis.
Vitamins are categorized according to solubility
characteristics. Vitamins A, D, E, and Kare called
the fat soluble vitamins. The B vitamins and
vitamin Care called the water soluble vitamins.
The fat soluble vitamins are stored in the pig's body
so that briefperiods ofdietary deficiency rarely
cause a problem because the pig can draw on
reserves. The water soluble vitamins, because they
are not stored in the body, must be present in the
diet on a more or less regular basis.
In Canada, all diets based on cereal grains must be
supplemented with vitamins A, D, E, K, and B12
, as
well as riboflavin, niacin, and pantothenic acid.
Sow diets should contain added choline, and prob-
ably folic acid and biotin. Other vitamins, if
supplemented, are probably being included only as
a safety factor.
Vitamin Stability
Vitamin supplements deteriorate with age; certain
environmental factors accelerate the rate ofdeterio-
ration. Agents that tend to stimulate vitamin degra-
dation include moisture, oxygen (air), light, and
heat. pH is another concern but the producer can do
little to regulate it, for pH regulation is the feed
supplier's responsibility. A producer must be aware
41
ofthe situations that increase vitamin breakdown
and avoid them as much as possible. In general, the
fat soluble vitamins are less stable than the water
soluble vitamins. There are exceptions; for exam-
ple, vitamin C is very unstable in the diet.
Vitamin supplement manufacturers have recog-
nized the problem of stability. Vitamins A, D, and
E are supplied encased in gelatin that protect them
from breakdown, but which still allow for absorp-
tion in the gut. These gelatin beads also contain
anti-oxidants which provide further protection for
the vitamins inside.
The presence oftrace minerals, such as copper
and iron, in the diet tend to increase the breakdown
ofsome vitamins. Poor quality fats may also cause
a problem. The concern regarding trace minerals is
greater in premixes than complete feeds since in a
premix, trace minerals are present in much higher
relative concentrations and are thus in more intimate
contact with vitamins.
Choline chloride is a particular stress factor for
vitamins. Breakdown can be as much as three to
four times higher in premixes containing choline
chloride than those without it.
Table 3-18 summarizes information on the stabil-
ity of individual vitamins. To ensure maximum
vitamin stability, premixes should be stored in a
cool, dry, dark location and inventories should be
turned over reasonably quickly, particularly in the
summer when the temperature and humidity rise.
A premix containing only vitamins can be stored
up to 6 months with minimal deterioration, except
for folic acid, which deteriorates more rapidly.
Vitamin-trace mineral premixes, sometimes called
micro-premixes, which do not contain calcium,
phosphorus, or salt, can be stored up to 4 months.
However, losses ofsome vitamins under good
storage conditions will exceed 10%. Folic acid and
vitamin C, ifpresent, are the least stable vitamins in
such premixes.
Macro-premixes, which contain supplements of
all vitamins and minerals (micro and
macrominerals) should not be stored for more than

60. four months, since losses in excess of I 0% can
occur for many vitamins including folic acid,
pyridoxine, vitamin 03
,vitamin A, thiamine,
menadione (vitamin K), and if present, vitamin C.
The maximum time for storing complete feeds is
probably 4 months; losses of I 0% or more will
occur after that period. Vitamins C and K, and
thiamine will be particularly affected.
Acceptable storage periods can be increased if
extra vitamins are added to the premix. By provid-
ing large overages, shelf-life is extended because
losses due to storage are offset by higher original
vitamin concentrations. Actual overages can be
calculated based on expected losses due to process-
ing and length of the storage time (Table 3 - 18).
Vitamin A
Vitamin A, known chemically as retinol, plays a
major role in vision, bone development, reproduc-
tion, and in the formation of mucous membranes
(i.e., lining ofthe lungs and intestine). Vitamin A
deficiency can result in night blindness or un-co-
ordination. In sows, a deficiency may result in the
birth of dead. weak, or malformed piglets. Signs of
vitamin A deficiency include fetuses with small or
no eyes, a cleft palate, or hydrocephalus. These
symptoms, however, can be caused by other factors,
including some ofgenetic origin, so a vitamin A
deficiency cannot be diagnosed merely on the basis
ofmalformed piglets. Vitamin A deficiency in the
sow will not cause abortion. In any event, vitamin
A deficiency is rare now that diets are properly
supplemented.
Vitamin A is readily destroyed when exposed to
heat, moisture. and light. The process can be
accelerated if the vitamin is in close contact with
trace minerals and/or unstable fats. Vitamin A
activity can best be maintained by storing the feed
in a dry, cool, dark area.
Vitamin A in feed is supplied as esters (com-
pounds), such as vitamin A palmitate or vitamin A
acetate, which are more stable than other forms.
They are also manufactured in tiny gelatin capsules
that reduce deterioration rate and ensure both
stability and uniform distribution. Anti-oxidants are
often added to provide further protection. Perhaps
the greatest danger exists in vitamin-mineral
premixes that contain both vitamin A and trace
minerals. For this reason, it is wise not to keep such
premixes longer than 4 months. Because modem
vitamin A sources are stable and because most
premixes contain far more vitamin A than a pig
actually requires, a 4 month storage period should
not be excessive provided the premix is kept dry
and is not heated or exposed to light.
Vitamin A concentration is expressed in Interna-
tional Units (IU), an arbitrary scale that permits
comparison among different sources. One IU of
vitamin A is equivalent to 0.3 ug ofretinol (vitamin
A alcohol), 0.344 ug ofretinyl acetate (vitamin A
acetate) or 0.55 ug retinyl palmitate (vitamin A
palmitate).
Fish oils are good natural sources ofvitamin A.
Alfalfa meal contains carotenoids which are chemi-
cals that the animal can convert to vitamin A. As a
rule, one can assume that for swine, 1 mg ofBeta-
carotene is equivalent to 260 TU ofvitamin A.
There are some indications that Beta-carotene itself
plays a role in swine reproduction, independent of
vitamin A. However, more research is required in
this area. For example, some studies indicate that
Beta-carotene appears effective only when adminis-
tered via injections and not when included in the
feed. Other studies suggest that vitamin A, when
administered in an injectable form, may enhance
reproductive performance in sowsjust like inject-
able Beta-carotene.
Beta-carotene is widely distributed in certain
foods. Most green materials, such as alfalfa, are
relatively rich in Beta-carotene since it is generally
associated with chlorophyll (the compound which
imparts the green colours in plants). There are
exceptions, such as carrots and tomatoes, which
contain carotene but not chlorophyll. A compound
called xanthophyll, although part ofthe carotenoid
family, has no vitamin A value. It is often used in
poultry rations based on cereal grains to provide the
yellow pigment in egg yolks, but xanthophyll has
no value in swine diets.
42

61. Hays may lose much oftheir vitamin A activity if
left in the sun too long to cure, since heat and
sunlight destroy the carotenes. Cereal grains
contain essentially no vitamin A.
Vitamin D
A pig requires vitamin D for the proper utilization
ofcalcium and phosphorus, including stimulating
the gut to absorb them. Vitamin D also plays a very
important role in normal bone metabolism. A
vitamin D deficiency is most likely to appear as
lameness or other signs of disturbed calcium and
phosphorus utilization. Pigs that are deficient may
have swollen joints, broken bones, or stiffness.
However, various infectious agents can also cause
stiffness and swelling so determination ofa vitamin
D deficiency cannot be made without detailed
diagnostic tests.
Vitamin D is formed naturally by exposure of the
pig's skin to sunlight. The ultraviolet rays in
sunlight activate an enzyme responsible for convert-
ing a natural compound (7-dchydrocalciferol) into
vitamin D. For this reason, pigs housed indoors
require preformed vitamin D supplements in their
diet.
Stability concerns, similar to those described for
vitamin A, also exist for vitamin D, although it is a
somewhat more stable compound. Modern
processing methods, generous diet formulation
standards, and proper storage practices combine to
overcome potential concerns. ln terms ofnatural
sources, most fish oils are excellent. Cereal grains
contain no vitamin D.
Table 3-18. Stability ofVitamins in Premixes and During Pelleting and Extrusion.
Stability
Very High High Moderate Low Ver:i::Low
Vitamin Choline Riboflavin Thiamine Mono Thiamine Menadione
Chloride Niacin Folic Acid HCI Ascorbic
B12 Pantothenic Pyrodoxine acid
acid, E DJ
Biotin A
(losses/month)
Premixes without
choline and trace 0 <0.5% 0.5% 1% 2%
minerals
Premixes with <0.5% 0.5% 2% 4% 6%
choline
Premixes with
choline and <0.5% 1% 8% 15% 30%
trace minerals
Pelleting 1% 2% 6% 10% 26%
Extrusion 1% 5% 11% 17% 50%
Source: BASF Technical Bulletin.
43

62. There are two chemical forms ofvitamin D
referred to as vitamin 02
, also called ergocalciferol,
and vitamin 03
, known as cholecalciferol. Vitamin
03
is the only form available in commercial supple-
ments since poultry have difficulty utilizing Vitamin
02
and because the cost of manufacturing vitamin
D2
is greater than that for vitamin Dr Vitamin D
activity is expressed in International Units, where l
TU is equivalent to 0.025 ug ofpure vitamin 03
•
Excess vitamin D must be avoided because it can
lead to many health problems, such as accumulation
ofcalcium in the kidney and blood vessels which,
in severe cases, will cause death. In some parts of
the world, high potency vitamin D preparations are
used as rat poison.
Vitamin E
Vitamin E is actually a general name for a group
of compounds called tocopherols and tocotrienols.
Alpha-tocopherol is the most active and also the
most widespread in nature. A pig requires vitamin
E for many functions, including normal muscle
activity and reproduction. Vitamin E helps to
prevent the membrane surrounding individual cells
from deteriorating, influences the production of
various hormones, and defends against infection.
Because of its involvement in maintaining cell
membranes, increased vitamin E levels in pig
finisher diets have been related to reduced drip
losses and reduced incidence of pale meat in swine
and beefcarcasses.
Vitamin E deficiency symptoms include muscle
weakness and liver damage. Reproductive impair-
ment is often used as a sign ofvitamin E deficiency,
but because the sow can store vitamin E for a long
time and in considerable quantities, effects on litter
size are extremely rare.
Researchers now know that vitamin E acts with
selenium to protect against some diseases. Thus,
nutritionists take great care to ensure that both
vitamin E and selenium are properly supplemented
in a diet. Ifone is deficient, the requirement ofthe
other is raised. Conversely, a high dietary level of
one reduces, but does not eliminate, the need for the
other. A vitamin E deficiency can be prevented by
supplying a properly balanced diet containing both
vitamin E and selenium supplements.
On occasion, a symptom ofvitamin E deficiency,
hypersensitivity to iron injections in young pigs, is
reported. Piglets die soon after receiving an iron
injection due to iron's oxidizing effects. The
solution is to treat the pregnant sow with vitamin El
selenium injections so that she transmits protection
to the fetus directly and to the piglet, after
farrowing, via her milk.
Mulberry heart disease is occasionally diagnosed
in swine and is attributable to a dietary deficiency
of vitamin E and/or selenium. Care must be taken
in diagnosing mulberry heart disease. Infection
with Strep. suis Type II can induce similar
symptoms. Ifyou suspect a problem, consult a
veterinary pathologist familiar with the disease.
Vitamin E in the diet is inherently unstable,
especially in the presence ofrancidifying
(improperly stabilized) fats. Vitamin E is also
expensive so that over-formulation, a common
practice with vitamins A and D, is less common.
Therefore, vitamin E represents a greater concern
with respect to the longevity ofvitamin-mineral
premixes. The four month feed storage rule still
applies provided care in storage and handling is
exercised.
Vitamin E requirements are expressed in mg,
International Units (IU) or United States
Pharmacopeia (USP) units. It is important to be
44

63. able to interchange these measurements because
different sources may be expressed in different
ways. One IU ofvitamin Eis equivalent to I USP
unit which in turn equals l mg ofdl-a-tocopheryl
acetate, 0.74 mg ofd-a-tocopheryl acetate, 0.91 mg
ofdl-a-tocopherol, and 0.67 mg of d-a-tocopherol.
The acetate form is preferred because it is more
stable.
Vitamin Eis present in many feedstuffs but can be
destroyed by curing, artificial drying (ofgrains),
and storage. The tocopherol content ofmany feed
ingredients are listed in Table 3-19. However, in
practical swine diets, sufficient supplemental
vitamin E is added to meet requirements so the
natural sources provide an additional safety margin.
Table 3-19. Alpha-tocopherol Content (mg/kg) of
Feed lngredients.
Ingredient Mean Range
Alfalfa meal 49.8 3 - 106
Barley 7.4 4 - 11
Blood meal 1.0 0-4
Canola meal 14.5 10 - 19
Com 3.1 0 - 21
Com germ 22.7 2 - 49
Corn gluten meal 6.7 3 - 12
Cottonseed meal 17.3 3 - 32
Feather meal 7.3 5-8
Linseed meal 4.0
Meat meal 1.2 0-5
Oats 7.8 4 - 11
Peanut meal 2.7 2-4
Poultry by-product meal 6.0 0 - 16
Rice 2.3 2 - 2.4
Rye 9.0 2 - 14
Sorghum 5.0 1 - 16
Soybeans 21.0
Soybean meal 2.3 0-8
Sunflowers 10.4 4 - 18
Sunflower meal 5.0
Wheat 11.6 5 - 30
Wheat bran 16.5 10 - 25
Wheat middlings 20.1 2 - 41
Whey (dried) 0.3 0 - I
Source: Hoffman LaRoche Ltd. 1988
45
Vitamin B12
Vitamin B12
, also known as cyanocobalamine, is
required in extremely small quantities in the diet. It
used to be called the 'animal protein factor' because
before Vitamin B12
was discovered, producers knew
that animals receiving diets containing ingredients
solely ofplant origin would develop pernicious
anaemia. Now we know that plants are incapable of
producing vitamin B12
so diets based on grains are
completely devoid of it. Today, synthetic vitamin
B12
is readily available so pigs can grow quite well
on diets devoid ofanimal products. The vitamin is
synthesized by bacteria so that pigs with access to
feces can obtain vitamin B12
from this source.
Vitamin B12
cannot be absorbed from the gut
without the aid ofthe 'intrinsic factor', which is
secreted by the stomach of healthy animals. Ab-
sence of intrinsic factor, even with adequate vitamin
B12
, will result in pernicious anaemia.
Vitamin B12
deficiency results in anaemia, slow
growth, poor co-ordination ofthe hind legs, and
rough hair coat. Longer term deficiency causes
nerve degeneration. The impact ofa deficiency is
much greater in young animals than adults. Severe
cases can result in high mortality among affected
animals. Vitamin B12
deficiency can also alter the
structure ofbackfat in pigs leading to the accumula-
tion ofodd chain fatty acids.
Cobalt is a part of vitamin B12
• Cobalt's main
function in the body is to work within vitamin B1
/s
structure. Diets supplemented with vitamin B12
,
need no extra cobalt. Synthetic sources, simply
called vitamin B12
, are available for use in diets.
Vitamin C
In the animal kingdom, only a few species,
including man and monkeys, require supplemental
vitamin C (ascorbic acid). All other species, includ-
ing pigs, possess an enzyme that converts glucose to
vitamin C. There is some indication that young pigs
may benefit from the addition of vitamin C to their
diet, but the available information is not conclusive.
Biotin
Biotin is involved directly or indirectly in energy
and carbohydrate metabolism, fat synthesis and
breakdown, amino acid metabolism, protein

64. synthesis, nitrogen excretion, and the maintenance
of hair, skin, nerves, and sex glands. A deficiency
results in impaired growth rate, dermatitis, loss of
appetite, and spasticity ofthe hind legs.
Biotin is found in cereal grains and other
ingredients commonly fed to swine. The
availability of natural biotin in most feedstuffs tends
to be poor and variable. The biotin in com is more
available than that in wheat, but there is much less
of it. Thus, the earlier beliefthat supplemental
biotin is not required in swine diets has been
reconsidered and common practice now includes
biotin in diets for the breeding herd and growing
boars and gilts that may be selected for breeding.
Avidin, a naturally occurring compound in egg
whites that binds with biotin and makes it
nutritionally unavailable, can be added to swine
diets to induce deficiency symptoms. On the basis
ofthis research, we now understand that sows
deficient in biotin may develop hooflesions that
can lead to premature lameness. Various studies
show that adding biotin to sow diets increases
reproductive efficiency. Wheat or barley based sow
diets are generally supplemented with 150 to 250
mcg of biotin per kg ofdiet. Much higher levels are
used in some cases, but the benefits are far from
clear. Fifty to one hundred (50-100) mcg of biotin
may be added to barley or wheat based diets for
growing-finishing pigs. Since biotin is an
expensive vitamin, adding an excessive safety
margin does not make economic sense. When
required, biotin is available in synthetic form.
Choline
Choline, unlike other vitamins. is required in the
diet in a high concentration and acts more as a
structural component of the body rather than in
support ofchemical reactions. The body uses
choline to produce chemical messengers called
neurotransmitters which allow nerves to send
messages throughout the body. Choline also forms
part ofcell membranes, provides a surface active
agent required by the lungs, is involved in fat and
cholesterol rnctabolism, and acts as a precursor for
the formation ofthe amino acid, glycine. Signs of
choline deficiency include reduced weight gain,
rough hair coat. decreased red blood cell count, and
unbalanced and staggering gates.
Choline deficiency has been imp!icated as a cause
ofspraddle leg in swine although there is very little
scientific support. Many experiments have evalu-
ated the effect ofcholine on spraddle leg and none
have concluded that choline was beneficial. The
use ofcholine to prevent spraddle leg is question-
able and should be carefully considered from a
cost:benefit perspective. Some producers spend as
much as five or six dollars per tonne of sow diet to
provide generous supplementation ofcholine.
Using good flooring materials that improve footing
in the farrowing crates has proven to be a more
effective solution to the problem at less cost. Other
approaches, such as tracing genetic predisposition in
the breeding herd and removing parents ofpiglets
that seem predisposed to spraddle leg, is also
effective in some herds.
The pig can synthesize choline from the amino
acid, methionine. Thus, the dietary requirement for
supplemental choline will depend on the pig's
methionine status. Choline is supplied by the salt,
choline chloride. It is very hygroscopic (attracts
water) so must be carefully stored. Pure choline
chloride contains 86.78% choline. Commercial
supplements. available in dry forrn, contain either
50% or 60% choline chloride. Liquid choline
chloride (70%) is also available.
Folic Acid
Folic acid is the name given to the vitamin. while
the term, folacin, refers to compounds derived from
the vitamin. Folic acid is involved in a number of
functions, including cell division and growth, and
amino acid and nitrogen metabolism. Folic acid
deficiency results in anemia (different from that
caused by iron deficiency), reduced weight gains,
and fading hair colour.
Until recently, it was believed that normal dietary
ingredients plus gut synthesis provided sufficient
folic acid for pigs. Therefore, most swine diet
premixes did not contain supplemental folic acid.
However, recent information suggests that folic acid
improves reproductive performance in sows.
Prolonged administration ofsulpha drugs inhibits
growth ofthe bacteria that synthesize folic acid in
the gut. The need for supplementation may depend
on the use of drugs in a particular herd.
46

65. Menadione
Menadione, a more common name for vitamin K,
is involved in calcium and vitamin D metabolism.
The blood requires vitamin K to form clots; a
deficiency results in prolonged clotting time and in
severe cases, haemorrhaging. A compound called
dicoumarol, found in spoiled sweet clover, reduces
the blood's prothrombin content and raises the
requirement for menadione supplementation.
Certain mycotoxins in the diet may have the same
effect. Sulpha drugs can reduce bacterial synthesis
and place greater pressure on dietary sources of
menadione.
Vitamin K is supplemented in diets by a number
ofcompounds, such as menadione
dimethylpyrimidinol bisulphite (MPB-22.7%
menadione), and menadione sodium bisulfite
complex (MSBC-33.0 or 16.5% menadione).
Alfalfa meal is a rich. natural source ofmenadione.
Niacin
Another name for niacin is nicotinamide, which is
the biologically active form ofthe vitamin. Niacin
is a relatively stable compound not adversely
affected by heat. It is involved in the metabolism of
many dietary components including fats, carbohy-
drates, and proteins. Because ofniacin's central
role in metabolism, nutritionists are careful to avoid
a deficiency. Deficiency symptoms include reduced
weight gain, dry skin, poor appetite, and diarrhea.
Cereal grains contain considerable quantities of
niacin but its availability in corn, wheat, oats, and
sorghum is poor. Conversely, the niacin in
soybeans is highly available. Niacin is readily
available in synthetic form at a reasonable cost for
supplementation in swine diets.
Tryptophan in the body can act as a precursor for
niacin; diets containing excess tryptophan require
less niacin. A diet marginal in tryptophan will place
greater pressure on the need for niacin. However,
tryptophan is the second or third limiting amino
acid in diets based on corn, so dietary tryptophan is
unlikely to provide appreciable amounts ofniacin.
Theoretically, 50.0 mg of tryptophan will provide
1.0 mg of niacin.
Pantothenic Acid
Pantothenic acid was formerly known as vitamin
B5• As a component ofone specific co-enzyme, co-
enzyme A, pantothenic acid is important for fat and
carbohydrate metabolism. Deficiency symptoms
include slow growth, diarrhea. dry skin, reduced
immune response, and a peculiar behaviour known
as 'goose stepping' in the hind legs.
The name pantotbenic acid is derived from the
Greek word 'pantothen' which means 'from every-
where'. As its name suggests, pantothenic acid is
found in many feed ingredients. Barley, wheat, and
soybean meal are good sources, but biological
availability in corn and sorghum is low. Although
cereal grains are good sources of the vitamin, swine
diets are generally supplemented with the synthetic
form called d-calcium pantothenate (88.3% d-
pantothenic acid). The form called di-calcium
pantothenate provides 44.0% d-pantothenic acid,
since the I-isomer is biologically inactive.
Pyridoxine
Pyridoxine was formerly called vitamin 86
.
Pyridoxine, like other vitamins, plays an important
role in enzyme function. Over 50 pyridoxine-
dependent enzymes have been identified.
Pyridoxine is particularly important in amino acid
metabolism and the formation of neurotransmitters,
the chemical messengers of the nervous system.
Deficiency symptoms include reduced appetite and
growth rate. In severe cases, nervous disorders.
including convulsions, occur.
Cereal grains are good dietary sources of
pyridoxine. Because ofthe wide distribution of
pyridoxine in conunon feed ingredients, pyridoxine
deficiency in swine is very rare and most diets, with
the possible exception ofstarter diets, are not
normally supplemented.
Riboflavin
Riboflavin is a critical co-factor in energy
metabolism and also plays a role in fetus
development. Formerly called vitamin B2
,
riboflavin is supplemented in all swine diets
because cereals are a poor natural source. Whey
powder, commonly used in starter diets, is the only
47

66. ingredient used in swine diets that is a good source
ofriboflavin. Supplemental riboflavin is available
commercially as a 96% pure powder.
Riboflavin deficiency results in anestrus in gilts.
cataracts, a stiff gait, and reduced growth rate. It is
also teratogenic, meaning a deficiency results in the
birth of deformed piglets.
Thiamine
Thiamine was once called vitamin 81
• A pig's
requirement for thiamine increases in proportion to
its energy intake because thiamine is required to
maintain normal energy metabolism. Symptoms of
deficiency include depressed appetite, vomiting,
depressed body temperature, and a slower than
normal heart rate. Deficiency (for research
purposes) can be induced by feeding raw fish,
which contains the enzyme, thiaminase, that
destroys thiamine.
Grains are generally good sources ofthiamine.
Thiamine is present in the germ and hull portion of
cereals so wheat germ and bran contain very high
levels ofthiamine. Flour, because ofits limited
quantity ofwheat germ and bran, is a poor source of
thiamine. Diets are not generally supplemented
with thiamine because most common ingredients
are rich sources ofthe vitamin. Some nutritionists
believe supplementation is required, especially in a
young pig's diet, so small amounts (1 mg/kg) may
be added to starter diets. Synthetic thiamine is
usually provided as thiamine hydrochloride (89%
thiamine) or thiamine mononitrate (92% thiamine).
Essential Fatty Acids
As indicated previously, dietary fats are made up
ofsub-units called fatty acids. At least one, linoleic
acid, is essential in a pig's diet. Linoleic acid, a
member of the omega-6 family offatty acids, is a
dietary essential because it performs a specific role
and cannot be synthesized from other compounds.
Linolenic acid, a member of the omega-3 family of
fatty acids, may also be required in the diet. A
third fatty acid, arachadonic acid, also a member of
the omcga-6 family of fatty acids, can be consid-
ered a semi-essential fatty acid. Pigs require
arachadonic acid but can synthesize it from linoleic
acid ifsupplied in sufficient quantities in the diet.
The essential fatty acids (EFA) perform a number
offunctions. They become an important part ofcell
membranes. thus help to ensure that cells function
normally. They are also involved in the synthesis of
a group of very important hormones called
prostaglandins. These hormones are required for
many body functions, including reproduction.
The requirements foressential fatty acids inpig diets
are not well established. The recent interest in the
role ofessential fatty acids in human health has revived
the interest in the metabolism and utilization of
essential fatty acids by pigs as well. There is, for
example, considerable debate on the efficiency with
which pigs can convert linolenic acid to other
polyunsaturated fatty acids that belong to the family
ofomega-6 fatty acids and that are requiredfor normal
animal metabolism and reproduction. Some studies
suggest that the ratio of omega-6 to omega-3 fatty
acids in the diet is as important for the conversion of
these omega-3 fatty acids as the levels ofthese fatty
acids in the diet itself. An essential fatty acid
deficiency is unlikely in normal diets for growing
swine because the requirement appears to be very low
(approximately O. l - 0.3% of the diet) and because
vegetable fats tend to be good sources. Even the small
amount of fat present in wheat or barley apparently
supplies more than sufficient EFA to meet
requirements.
The actual requirements for EFA by sows and boars,
however, are difficult to establish. The synthesis of
some important reproductive hormones depends on
EFA: the requirement for the breeding herd is
suspected to be substantially higher than it is for
growing animals. Because EFA is stored in body fat
reserves, any signs of deficiencies in sows may not
occur until the third or fourth parity. Based on a
factorial estimation, sows may require 0.75% linoleic
acid in the diet. If this estimate is indeed correct, a
barley-soybean meal based diet may be deficient in
linoleic acid. No estimates are available for the
requirements for linolenic and arachidonic acid in
swine.
An EFA deficiency will impair growth rate and feed
utilization, cause dry, scaly skin, and possibly result
in hair loss. Reproductive performance also suffers.
One experiment demonstrated that EFA deficiency
48

67. resulted in impaired water holding capacity ofmuscle, N.F.l.A. 1981. Specialty ingredients handbook. Na-
and that heart muscle structure and colour changed. tional Feed Ingredients Association. West Des Ma-
rines, IA.
Vegetable fats are rich sources of EFAs. The rea-
son cereal-based diets present a deficiency risk is be-
cause barley and wheat contain much less fat than com.
The recent practice ofadding vegetable oil, or whole
seed canola or soybeans to sow diets should remove
all concern about a possible deficiency. The fact that
the requirement has not been defined, however, leaves
some room for question.
Water
Water is often called the 'forgotten nutrient' because
it is so often ignored. Yet, water is as important as
any other dietary component and must be supplied in
sufficient quantities to ensure maximum productivity.
Water is critical to life and good health. For detailed
information on water, refer to chapter 12.
NRC 1980. Mineral tolerance ofdomestic animals.
National Academy of Sciences. Washington, D.C.
NRC 1988. Nutrient requirements of swine. 9th
Edition. National Academy of Sciences. Washing-
ton, DC.
Noblet, J. and Y. Henry. 1991. Energy evaluation
systems in pig diets. Manipulating Pig Production
Ill. Australasian Pig Science Association, Attwood,
Victoria, Australia. pp. 87-103
Noblet, J. and J.M. Perez. 1993. Prediction of di-
gestibility ofnutrients and energy values ofpig diets
from chemical analyses. J. Anim. Sci. 71: 3339-
3398.
Standing Committee on Agriculture (SCA). 1987.
Feeding standards fro Australian livestock. V, Pigs.
Editorial and publishing unit, CSIRO, East Mel-
bourne. Australia.
Sauer, W.C. and L. Ozimek. 1986. Digestibilities of
amino acids in swine: results and applications. Lives.
Prod. Sci. 15:367-388.
Van Soest, P.J. 1982. Nutritional ecology of the ru-
minant. 0 & B Books, Inc. Cowallis, OR
Graham, H. 1988. Dietary fibre concentration and
assimilation in swine. Anim. Plant. Sci. I :76-80.
Additional Reading and References
A.RC. 1981. Nutrient requirements ofpigs. Agri-
cultural Research Council, Commonwealth Agricul-
tural Bureau, Slough.
Batterham, E.S. 1993. Availability ofamino acids in
feeds. Manipulating Pig Production IV Australasisan
Pig Sciences Association, Attwood, Victoria, Aus-
tralia. pp 197-203.
Theander, 0. and E.A. Westerlund. 1986. Studies on
dietary fibres. 3 Improved procedures for analysis of
Batterham, E.S. 1989. Prediction ofthe energy value dietary fiber. J. Agric. Food Chem. 34:330-336.
ofdiets and raw materials for pigs. Feedstuffs Evalu-
ation. Butterworths, London. pp 267-282.
Whittemore, C.T. 1993. The Science and Practise of
PigProduction. Longman House, Burnt Mill, Harlow,
Miller, R.M., D.E. Ullrey and A.J. Lewis (Ed.) 1991. Essex, England.
Swine Nutrition. Butterworth-Heinemann, Stoneham,
MA.
Moughan, P.J. 1991. Towards an improved utiliza-
tion of dietary amino acids by the growing pig. Re-
cent Advances in Animal Nutrition, 1991.
Butterworths, Heineman, Oxford. pp. 45-64.
49

68. 50

69. 4. INGREDIENTS
The science of nutrition, as it applies to diet
formulation, involves essentially five steps, as
outlined in chapter 5: define feeding objectives,
establishment requirements needed to achieve the
objectives, select ingredients, formulate diets and
evaluate diets once made. This chapter focuses on
ingredients and how they might be used in diets.
In recent years, swine nutritionists have made
huge advances in defining the pig's nutrient require-
ments and further developments in this area are
almost a certainty. Progress in defining the nutrient
specifications ofingredients has been somewhat
slower and now provides a serious challenge to
commercial nutritionists. The precision with which
we can define nutrients supplied to the animal
appears to be considerably less than that with which
we can define nutrients required by the pig. The
two major challenges relate to nutrient variability
and nutrient availability. Consequently, to consist-
ently achieve the level ofanimal performance
expected on an ongoing basis, and to do so at the
lowest possible cost, nutritionists must address these
two issues. Failure to do so will result in either
excessive feed costs or variable animal performance
or both!
Ingredient Versus Nutrient
Pig diets should be formulated primarily from the
perspective ofnutrients and less so on the basis of
ingredients. Over many centuries ofdomestication,
the pig has demonstrated a marvellous ability to
perform successfully using a diverse array of ingre-
dients; the pig is an omnivore, meaning it has the
ability to utilize feedstuffs ofanimal or vegetable
origin. The history ofthe pig is filled with exam-
ples ofthis culinary diversity.
lndeed, the future success ofpork production
probably rests, in part, on our ability to utilize many
ingredients effectively in pig diets. In localized
areas, or on a regional basis, successful pork pro-
ducers seek out and utilize ingredients that are
discounted for reasons that arc often founded less on
nutritive value than on tradition and personal prefer-
ence. For those readers whose experience with
feeding pigs is limited to using one or two grains
(wheat, barley, corn) and one protein source (soy-
bean meal), it would be a worthwhile exercise to
study diets utilized in other parts ofthe world,
where these ingredients represent less than halfof
the total diet, the remainder consisting of other crop
(eg. lupins, peas, canola, tapioca) or animal (blood
meal, meat and bone meal, feather meal) products.
Nutrient based diet formulation, or formulation
on the basis ofnutrients irrespective ofsource, is
not new, but a surprisingly significant emphasis on
ingredients remains in our culture. While com and
soybean meal may represent a standard against
which other ingredients may be compared, and
therefore give a level ofcomfort to pork producers
due to experience and tradition, it is essential to
recognize that equivalent performance can be
achieved with many other ingredients.
Therefore, ingredients should be selected on the
basis ofcomposition, cost, availability and palat-
ability. There is nothing magical about one ingredi-
ent versus another, provided resulting diets are
properly formulated.
Composition is the first consideration. ls the
nutrient composition ofan ingredient known with
some reasonable degree ofaccuracy? If so, the
ingredient can be used to its maximum level with
confidence. Ifnot, then nutritionists tend to be
more conservative and use less than they otherwise
might.just to avoid unpleasant surprises!
51

70. Table 4-1. Consistency of Various Protein Sources Used in Swine Diets.
Number Protein Content
Ingredient of Samples Average Range Standard Deviation
Plant Sources
Barley 25 1 1.1 9.5 - 12.4 0.80
Wheat 26 13.4 11.6 - 15.6 0.92
Corn 20 9.2 8.2 - 11.l 0.85
Oats 9 10.4 8.4 - 12. l 1.25
Soybean meal 32 47.4 46.l - 48.8 0.52
Canola meal 42 34.2 32.7 - 36.3 0.79
Animal Sources
Fish Meal 5 62.7 60.3 - 66.6 2.72
Meat Meal* 29 54.2 49.8 - 58.5 2.04
"This analysis contains data from samples described as both meat meal and animal or feeding tankage.
Example of variation in protein content observed in commercial samples ofthe ingredients listed. Above example
refers to samples collected and analysed during April and May, J995.
Supplied by Federated Co-operatives Ltd.., Saskatoon, Saskatchewan.
Based on nutrient composition, can the ingredient
be included in the diet and still meet the needs of
the pig? For example, corn can be used in place of
wheat, or vice versa, in a starter diet, because they
are both high energy grains. Oats would not be
used to replace either wheat or corn, because they
are too low in energy.
Is the composition consistent? As a rule, proteins
derived from vegetable sources, such as soybean
meal or canola meal, are relatively consistent from
batch to batch and from supplier to supplier. Con-
versely, protein supplements manufactured as part
ofthe meat processing industry tend to be Jess
consistent. One can obviously use a consistent
product with a greater degree ofconfidence. Table
4-1 illustrates this point. Quality control data
supplied by the Feed Department ofFederated Co-
operatives Ltd. shows that products ofplant origin
tend to be relatively consistent, as indicated by a
smaller standard deviation (a measure ofvariabil-
ity). Products of animal origin tend to be less
consistent and have a larger standard deviation.
This does not mean that they should not be used,
but rather that more caution needs to attend their
inclusion in the diet. Advances in the technology
52
associated with processing ofoffal is resulting in a
more consistent product than was possible in the
past.
Does the ingredient contain any anti-nutritive or
toxic compounds? For example, the old rapeseed
meal contained glucosinolates that reduced feed
intake and impaired animal health. The new canola
meal has essentially eliminated such problems.
Based on composition, is the product economical
compared to other available ingredients? Cost
should be considered in terms ofprofit, not price
per tonne. Ifan ingredient can reduce the overall
cost ofproduction, it should be used. If not, a more
economical ingredient should be selected.
Finally, is the ingredient appealing to the pig?
This is a difficult question to answer, because pigs
have a limited vocabulary! Unfortunately, we tend
to think we know what is attractive to the pig. It is
very important that one does not use human values
to select ingredients for pig feed. Pigs eat many
things that humans will not, and indeed. there are
things that humans will eat that pigs find
unappealing.

71. INGREDIENT
Is its nutrient composition, including availability,
known?
The basis for diet formulation is knowledge.
Lack ofknowledge means uncertainty and this
translates into errors. The flow diagram in Figure
4-1 helps determine ingredient usage.
The following section contains a discussion on the
utilization ofcommon and some not so common
ingredients in swine diets. Detailed feedstuff
composition tables appear in the Appendix. For
further information on a particular ingredient, useful
articles are listed at the end ofthe chapter.
Animal Sources
The quality offeed ingredients derived from the
meat processing industry has improved consider-
ably in recent years. Improvements in quality
control have resulted in products that are superior to
that sold even ten years ago. As with any product,
quality varies among suppliers and attention to good
purchasing practices, including regular feed testing,
is advised.
This chapter discusses the use ofmany ingredients
in swine diets. Where possible, recommendations
for inclusion in the diet are provided. In providing
these guidelines, certain assumptions have been
made. For example, replacement of current ingredi-
ents with an alternative should not change the
overall nutrient composition ofthe diet. If so, a
depression in performance will probably occur.
Reject
No
�
No
�
Determine
nutrient
composition
Yes
Yes
IIs it economical?
Can the pig's nutrient
requirements be met
if this ingredient
is used?
Yes
Is it readily available?
Yes
I
Is it palatable to the pig
and safe to use?
No
�
Reject
No
Reject
A recent concern with many by-product meals
relates to their use in minimum disease herds. Since
offal can be contaminated with salmonella, or other
pathogens, meat and bone meal, feather meal and
blood meal are often excluded from diets destined
for herds with a high health status. Certainly, the
possibility ofcontamination exists, although mod-
em rendering plants are designed such that once the
rendered product leaves the cooking vats and is thus
sterilized, it cannot come in contact with incoming
uncooked material. While the risk ofre-contamina-
tion is always present, products not associated with
the rendering process may be at equivalent risk.
The onus is on the management of the rendering
plant and truckers, to ensure that contamination
does not occur.
Figure 4-1. Flow Diagram Showing Choices in
Selection of Ingredients Used in Practical Diets.
Yes
Use the ingredient.
No
�
Reject
Ifthere is concern, the matter should be discussed
with a herd health veterinarian. In seeking zero risk,
by-product meals are often avoided by some pro-
ducers. However, they should be aware that other
protein meals can, and have, become contaminated,
probably during transport.
53

72. Blood Meal
Blood meal, as its name implies, is a high protein
ingredient manufactured from animal blood col-
lected from abattoirs. The nutrient composition of
blood meal will vary a great deal among suppliers,
due primarily to two factors: the method of process-
ing and the nature ofthe source material used in the
manufacturing ofthe product. Book values will not
suffice, unless extremely conservative values are
employed. For example, one study of five different
batches of blood meal revealed that total lysine
varied from 7.7 to 10.6% of the dry matter! Differ-
ences in digestibility of lysine would further in-
crease the variability of the product.
A variety ofprocesses can be used to convert raw
blood (approximately 20% dry matter) to the dry
powder useable in animal feeds. Vat drying is
essentially a batch process and results in the product
of lowest nutritional quality; in North America, vat
drying represents a very small portion ofthe total
blood meal available to the livestock industry. Vat-
dried blood meal is not recommended for use in
swine diets, as the availability ofnutrients is low;
for example, the cligestibility oflysine is probably
less than 20%.
The majority ofblood meals would be flash dried,
using the ring, roller, drum or belt methods. Ring-
dried blood meal is quantitatively the most common
product available in North America. In this process,
coagulated blood particles would be inserted into
rotating rings where high temperatures, in the range
of 550°C, force off the water, leaving a product
with as little as 5% total moisture. Flash-dried
blood meal is particularly popular in cattle feeds, as
the rumen degradability characteristics are highly
desirable in support of maximum animal perform-
ance. Ring-dried blood meal can be effectively
used in swine diets; typical recommendations
include up to 2% in later phase starter diets (pigs
over 15 kg) and up to 5% in growout and sow diets.
Increasing in popularity is spray-dried blood
meal. In this process, blood is treated with an anti-
coagulant to keep it in liquid form. It is pre-heated
and then spray-dried in vertical or horizontal cylin-
ders; retention times of2 minutes or less and
temperatures of less than 250°C are typical. In the
54
spray drying process, the lower temperatures and
shorter retention times, as compared to flash drying
results in a final product that is superior in terms of
amino acid availability. Spray-dried blood meal is
considerably more expensive than flash dried
product, and is used most commonly in starter diets,
especially those employed for the young pig. Phase
I diets may contain as much as 2% to 3% while
Phase III diets may contain up to 5% to 7% spray-
dried blood meal.
The use ofblood meal requires consideration be
paid to sulphur amino acid and branched chain
amino acid levels. There is research demonstrating
that starter diets containing blood meal may be
deficient in methionine, while higher levels of
blood meal (approaching 10%) in growout diets
may result in problems with Jeucine levels being
excessive or isoleucine levels being inadequate.
Unlike meat and bone meal, blood meal is not a
particularly good source ofcalcium or phosphorus.
The energy level in blood meal appears to be highly
variable, so individual suppliers should be asked to
provide DE or ME values for their product.
Blood Meal
DE 3050
Crude Protein 84.0
Lysine 7.60
Digestible Lysine 6.38
Digestible Threonine 3.11
Digestible Tryptophan 0.92
Calcium 0.50
Phosphorus 0.21
Blood meal is obviously a good source of iron.
However, iron supplementation is relatively inex-
pensive and indeed, the need for iron supplements
in market hog diets has been questioned. Thus,
attributing a value to blood meal for its iron content
would be questionable.
Blood meal tends to be hydroscopic, meaning that
it attracts water. Consequently, feeds containing
blood meal are more likely to bridge in the feeder,
so that feeder management is critical to ensuring
maximum feed intake is achieved.

73. Additional Reading and References
Miller, E.R. 1990. Blood meal: Flash dried. in
Non-traditional feed sources in swine production,
P.A. Thacker and R.A. Kirkwood, eds. London:
Butterworth. pp. 53 - 60.
greatly increase the processing time needed; how-
ever, excessive treatment periods, even at lower
temperatures appear lo resull in an inferior final
product.
Parsons, M.J., P.K. Ku and E.R. Miller. 1985.
Lysine availability in flash-dried blood meals for
swine. J. Anim. Sci. 60: 1447 - 1453.
Batterham, E.S., R.F Lowe, R.E. Darnell and E.J.
Major. 1986. Availability of lysine in meat meal,
meat and bone meal and blood meal as determined
by the slope-ratio assay with growing pigs, rats and
chicks and by chemical techniques. Brit. J. Nutr.
55:427 - 440.
Feather Meal
DE
Crude Protein
Lysine
Digestible Lysine
Digestible Threonine
Digestible Tryptophan
Calcium
Phosphorus
2250
85.0
1.67
1.09
2.54
0.29
0.34
0.93
Bone Meal
At one time, bone meal was a common ingredient
in animal diets, but more recently it has become too
expensive for routine use. It is an excellent source
of calcium and phosphorus, containing about 24%
and 12% respectively. However, products of equal
mineral value are now available at much less cost.
Bone Meal
Cmde Protein 28.0
Lysine 1.00
Digestible Lysine 0.77
Digestible Threonine 0.51
Calcium 30.00
Phosphorus 12.50
Feather Meal
Feather meal is a by-product of the poultry
processing industry. Although rich in crude protein,
raw chicken feathers are of little nutritional value to
the pig; the digestibility ofthe protein is essentially
zero. Commercially available feather meals are
often referred to as hydrolysed feather meal, be-
cause they are steam treated under pressure to
improve their nutritive value. For maximum
nutritive value, feathers need to be autoclaved for
30 to 60 minutes al l42°C to l 53°C (40-60 p.s.i.).
Higher pressures for shorter periods are also em-
ployed commercially. Lower final temperatures
Like most by-product ingredients ofanimal
origin, variability of nutritional quality is a major
concern. Even if total amino acid content does not
change, availability may differ vastly according to
processing method.
Very little research on feather meal has been
conducted with pigs. However, commercially
available feather meals have supported growth in
chicks equal to that ofsoybean meal, ifessential
amino acids are properly supplemented. For the
chick, methionine, lysine, histidine and tryptophan
were required. Since amino acid requirements of
the pig differ from those ofthe chick, different
amino acids may be needed. However, the clear
message is that feather meal can be used, provided
it is appropriately supplemented with deficient
nutrients.
Feather meal can be used successfully in the diet
of pigs if the nutrient composition is accurately
known. As a minimum, it can be used at the rate of
3-4% in grower or sow diets. Its use in starter diets
is not recommended unless it is known that the
product being used is of superior quality. These
levels are conservative and greater quantities can no
doubt be used, but care in balancing for essential
amino acids would become more critical.
Additional Reading and References
Papadopoulos, M.C. 1985. Processed chicken
feathers for poultry and swine: a review. Agric.
Wastes 14:275 - 290.
55

74. Fish Meal
Fish meals are high in protein (50 to 75%) and
amino acids. The protein is ofgood quality (espe-
cially high in methionine) and is generally highly
digestible. Due to fat content (approximately 10%)
the DE content is comparable to or higher than that
in soybean meal. The levels of most minerals,
particularly calcium and phosphorus are similar to
or higher than those in other protein sources. Phos-
phorus availability in fish meals is high.
Saltwater species of fish commonly used for fish
meal include menhaden, anchovy, herring, red fish,
tuna, salmon and white fish.
The quality offish meal will have important
effects on its feeding value. Factors that should be
considered include: the source material (type of
fish, whole fish vs fish offal), storage ofthe raw
material (partial decomposition before processing)
and processing (overheating, moulding, excessive
oil). For example, meal made from viscera will be
lower in mineral content than meal made from
whole fish or heads and frames.
Oxidizing oils present in fish meal may cause the
destruction ofvitamins A andE in the diet which
could result in a vitamin deficiency. It is therefore
imperative that antioxidants be added during
processing. Fresh fish products also contain high
levels ofthe enzyme thiaminase which acts to
destroy the B-vitamin thiamine. If fish meal is
properly heat-treated this enzyme will be destroyed.
However, in order to ensure that a vitamin defi-
ciency does not occur, it may be worthwhile to
consider supplementation ofthiamine when diets
containing high levels of fish silage are fed.
Another concern with the use of fish products is
the possible presence of high levels of mercury.
Fish accumulate mercury in their body tissues and
the possibility exists that pigs fed silage could
produce a carcass unacceptable to humans due to
mercury consumption. Fish products containing
more than .5 mg/kg of mercury should not be used
in swine rations.
56
Fish Meal: Herring
DE
Crude Protein
Lysine
Digestible Lysine
Digestible Threonine
Digestible Tryptophan
Calcium
Phosphorus
Fish Meal: Menhaden
DE
Crude Protein
Lysine
Digestible Lysine
Digestible Threonine
Digestible Tryptopban
Calcium
Phosphorus
3725
71.0
5.82
4.95
2.41
0.58
2.75
1.75
3700
61.2
4.82
4.10
1.94
0.52
5.11
2.92
Fish Meal: White
DE 3550
Crude Protein 63.8
Lysine 4.34
Digestible Lysine 3.69
Digestible Threonine 2.11
Digestible Tryptophan 0.50
Calcium 7.00
Phosphorus 3.50
Over the last years many studies have been
conducted that demonstrate the beneficial effects of
including good quality fish meal (select menhaden
or herring) in weaner and starter pig diets. Possible
explanations include diet palatability, good amino
acid balance and availability, content ofspecific
long chain poly-unsaturated fatty acids, an underes-
timation of the available energy content, and the
absence of an allergic response by the pig's gut to
fish meal (as observed with soybean meal). Good
quality fish meal is routinely included in diets for
young pigs (at levels up to 10%) to replace the more
expensive milk protein (primarily from dried skim
milk). It is generally too expensive to include fish
meal in the diet for grower-finisher pigs and sows.

75. When large quantities offish meal are used in
starter pig diets, close attention should be given to
the level of lactose (normally supplied by milk
products) and minerals (calcium and phosphorus) in
the diet. A concern with using fish meal in finish-
ing pig diets is its effect on meat quality. Problems
may arise with a fishy taint in carcasses from pigs
fed fish meals. This can largely be attributed to the
oil content of fish meal. In the finisher diet, the
amount of oil derived from fish products should not
exceed 1%.
Additional Reading and References
Gore, A.M., R.W. Seerly and M.J. Azain. 1989.
Menhaden fish meal and dried whey levels in starter
diets. Univ. Georgia Swine Res. Rep. P. 11.
Stoner, G.R., J.L. Nelssen and R.H. Hines. 1988.
Replacing dried skim milk with select menhaden
fish meal in a high nutrient dense diet. Kansas State
Univ. Swine Res. Rep. P. 57.
Stoner, G.R., J.N. Nelssen and R.D. Goodband.
1989. Effect of fish meal quality on the growth
performance ofweanling pigs. Kansas State Univ.
Res. Rep. P.70.
Wiseman, J., S. Jaggert, D.J.A. Cole and W.
Haresign. 1991. The digestion and utilization of
amino acids ofheat treated fish meal by growing-
finishing pigs. Anim. Prod. 53:215-225.
Fish Silage
Fish silage is produced by adding organic acids to
whole or parts offish. The addition ofacid acti-
vates enzymes present in the raw fish and thus
stimulates the break down ofthe tissue protein. The
resulting product has a nutrient content similar to
fish meal except that fish meal has a dry matter
content of about 90% while fish silage has a dry
matter content in the range of 15-30%.
The process ofmaking fish silage offers the
potential of utilizing wastes from the fishing indus-
try in areas where the quantity of waste material is
insufficient to justify the production of fish meal.
Producers with operations located in the vicinity of
these processing plants can obtain a high quality of
protein supplement at a relatively low cost and
thereby increase the efficiency and profitability of
their swine operations.
The potential feeding value offish silage is
determined mainly by the quality ofthe material
being ensiled. Fish silage produced using a high
percentage ofwhole fish will have a higher nutri-
tional value than will silage produced using offal.
In addition, the type offish used will affect the
quality of the silage produced. For example, silage
based on white fish is different from that based on
herring and it is important to differentiate between
these when discussing their nutritional value.
White fish silage has a dry matter content of about
20%. On a dry matter basis, it contains approxi-
mately 70% crude protein, 3% ether extract and
16% ash. In contrast, herring fish silage has a dry
matter content of about 35% and on a dry matter
basis, it contains only 43% crude protein and 8%
ash. However, it has an ether extract content of
over42%.
The energy and mineral content and amino acid
profile offish silage closely resembles that of fish
meal made from the same type ofraw material (see
section on fish meal). As a consequence, fish silage
would appear an excellent source ofprotein and
minerals for use as a supplement to cereal grains.
However, some of the concerns that apply to fish
meal (oxidizing oils, thiamin supplementation.
contamination with mercury, effect on carcass
quality) apply to fish silage as well (sec fish meal).
Fish silage can be used quite successfully in swine
rations. The results ofa research trial conducted at
the University ofGeorgia using weanling pigs fed
either 0. 3, 6 or 9% fish silage for six weeks are
presented in Table 4-2. It can be seen that the
performance of weanling pigs fed diets containing
3 or 6% fish silage was not significantly different
from the control group while those fed diets con-
taining 9% fish silage gained weight at a slower
rate. The major factor responsible for this reduction
in growth rate appeared to be a reduction in intake.
57

76. Table 4-2. Performance of Weanling Pigs Fed Diets
Containing Graded Levels of Fish Silage.
Fish Silage(%)
0 3 6 9
Daily gain (kg) 0.42 0.40 0.43 0.39
Daily feed (kg) 0.87 0.89 0.91 0.80
Feed conversion 2.07 2.22 2.12 2.07
Adapted: Tibbetts et al., 1981, J. Anim. Sci 52:93-100.
Growing pigs also perform well on fish silage.
The results ofan experiment conducted in Britain in
which growing pigs between 25 and 55 kg body
weight were fed diets containing 0, 5, 10 or 15%
fish silage arc presented in Table 4-3. The inclusion
of fish silage in the diet slightly reduced feed intake.
Pigs fed fish silage grew faster than those fed the
control diet without fish silage. Yet, there was no
difference in growth rate between pigs fed diets
containing 5, IO or 15% fish silage. Feed efficiency
was best when the inclusion level offish silage was
l0%. The experiment showed no significant effects
ofthe inclusion level offish silage on the various
carcass characteristics ofpigs slaughtered at 55 kg
body weight (dressing percentage. carcass weight.
backfat measurements, fatty acid profile of the
subcutaneous carcass fat). However it was noted
that the backfat was slightly more yellow in the
carcasses ofpigs fed the 15% fish meal diet.
Table 4-3. Performance of Growing Pigs (25 to 55 kg
body weight) Fed Diets Containing Graded Levels of
Oily Fish Silage (44% fat in the pure product).
Fish Silage(%)
0 5 10 15
Dailygain(kg) .65 .71 .73 .71
Dailyfccdintake(kg)l.43 1.42 1.41 l.40
Feed Conversion 2.23 2.0 I 1.96 1.99
P2 Backfat (mm) I 0.0 11.0 10.4 l 0.0
Adapted: Green ct al., 1988, Anim. Feed Sci. Techn.
21 :43-56.
58
There would appear to be some problems when it
comes to feeding fish silage to breeding stock. The
results ofone experiment in which fish silage was
fed to sows during gestation are shown in Table 4-4.
Preweaning mortality has been shown to be signifi-
cantly higher when diets containing 6% fish silage
arc fed to sows during gestation. The reason for
this increase in mortality has not been dctennined.
Table 4-4. Effect of Feeding Fish Silage on the
Reproductive Performance of Sows.
Control 6% Fish Silage
Pigs born alive 11.4 11. l
Birth weight (kg) 1.4 1.3
Pigs weaned 9.7 8.2
Weaning weight (kg) 4.4 4.4
Mortality(%) 14.9 26.1
Adapted: Tibbetts et al., 1981. J. Anim, Sci. 52:93-100.
The major problem using fish silage is finding an
acceptable method offeeding the product. Because
of the high moisture content ofthe silage, diets
containing fish silage must be mixed on a daily
basis or else the cereal portion ofthe ration may
start to spoil. In addition, rations containing high
levels offish silage tend to bridge iffed in tradi-
tional types offeeders. Therefore, unless an accept-
able method offeeding fish silage is developed, its
use will be limited to small scale producers who
mix and feed by band.
Additional Reading and References
Green, S., J. Wiseman and D.J.A. Cole. 1988.
Examination ofstability. and its effect on the
nutritive value, of fish silage in diets from growing
pigs. Anim. Feed Sci. Techn. 21 :43-56.
Tibbetts, G.W., R.W. Seerley, H.C. McCampbell,
and S.A. Vezey. 1981. An evaluation of an ensiled
waste fish product in swine diets. J. Anim. Sci.
52:93-100.

77. Meat and Bone Meal
Meat and bone meal, or often referred to as meat
meal, is a by-product from the animal packing
industry. The crude protein content of meat and
bone meal (50%) is slightly higher than that of
soybean meal while its amino acid profile is surpris-
ingly similar to that ofsoybean meal although
containing less tryptophan. However, the amino
acids in meat and bone meal are generally less
available to the pig (see below). The energy content
of meat meal varies due to differing mineral con-
tent, but overall is less than that ofbarley or canola
meal. The calcium and phosphorus content is a
bonus since phosphorus is an especially expensive
nutrient. Care must be taken to consider the sodium
and chloride (salt) content ofmeat meals. The salt
content has been reduced in recent years. but is still
sufficiently high to require adjustment ofadded salt,
especially in the diets of young pigs.
Meat and Bone Meal
DE 2825
Crude Protein 50.0
Lysine 2.70
Dig. Lysine 1.89
Dig. Threonine 1.09
Dig. Tryptophan 0.17
Calcium 9.50
Phosphorus 4.70
For example, in some samples ofmeat meal the
bone content is low. This will result in increases in
protein levels (sometimes as high as 60% protein
and 3.1% lysine) and reductions in mineral levels
(can be as low as 6.5% calcium and 3.5% phospho-
rus). The fat content ofmeat and bone meal is
usually about 8%, since any additional fat in the raw
material is removed in the processing of tallow.
Raw materials incorporated into meat and bone
meal include such things as trim, hides, heads, feet
and entrails. Although meat and bone meal are two
different products, the terms are often used inter-
changeably. Whether it contains bones or not has a
considerable influence on the nutritive value ofthe
final product. For example, as bone content rises,
the crude protein content tends to fall. The fat
59
content ofmeat meal is usually about 8%, since any
additional fat in the raw material is removed in the
processing tallow.
The major problem with meat and bone meal is
variability of nutrient composition. For example,
one survey ofonly 17 samples revealed lysine
content ranged from 2.38% to 3.86%. Tryptophan
varied even more, from 0.20% to 0.69% and
threonine ranged from 1.81 % to 2.72%. Amino
acids were not the only nutrient to vary. Calcium
content was 0.9% to 15.8%. This lack of uniformity
makes it a difficult product to use to maximum
advantage in swine diets.
The degree ofvariability will depend on a number
of factors. Ifthe meal is produced from a single
source ofrelatively constant composition, then the
meal will reflect this in being consistent. However,
it is made from a variety of ingredients, such as
whole carcasses, offal and blood, and contains beef,
poultry and swine, the final product will likewise be
less consistent. Ifthis can be considered in the diet
formulation, no harm will be done. For example,
hard offal, which includes bones, heads and hooves
is a less desirable component, because it results in a
meat meal with a poorer amino acid profile due to a
high collagen content. Soft offal, consisting ofgut
material, tends to produce a superior product with a
more desirable amino acid profile.
Meat meal has the potential to be an important
protein source in swine diets, provided certain
features of the products are recognized. Some meat
meal will contain a great deal ofconnective tissue.
Although this is protein, it is not well digested and
its amino acid profile is quite poor. Also, a high
mineral content in meat meal could cause a distur-
bance of the calcium:phosphorus ratio and possibly
cause a zinc deficiency, if the diet is not properly
formulated. Ifthe formulation takes into account
the calcium and phosphorus content of meat meal,
and indeed takes advantage ofthem to satisfy the
pig's requirements, then no harm will be done and
performance will be quite satisfactory.
Processing method can also be an important
factor. Excessive temperature will reduce nutrient
quality and performance will be depressed. For

78. example, increasing the cooking temperature from
I 25°C to I 50°C has been found to reduce lysine
availability from 84% to 38%.
As mentioned above, the amino acid availability
of meat meal tends to be lower than comparable
values for cereal grains and vegetable protein
sources, For example, various studies have con-
cluded that lysine is 54-67% available for meat and
bone meal, as compared to 81-87% for soybean
meal and 71 % for fish meal. However, some
individual meat and bone meal samples have lysine
availabilities equal to that ofsoybean meal.
A potential concern if including meat and bone
meal in pig feeds is its contamination with harmful,
disease causing organisms such as salmonella.
However, various recent surveys demonstrate that
the incidence ofsalmonella contamination in
properly processed meat and bone meals (proper
temperature, no contamination ofprocessed with
unprocessed material) is very low. In fact, some
surveys demonstrate that feedstuffs ofvegetable
origin, such as cereal grains and soybean meal can
be contaminated with salmonella as well. A further
point worth noting is that there are a whole range of
types ofsalmonellas. Only a very limited number
ofsalmonella strains are considered harmful to pigs
or humans.
Success in using meat and bone meal will depend
on one's ability to define nutrient composition.
High quality meal, purchased from a good supplier
with a sound quality control program, can be used
at high levels in market hog diets (10-15%) as well
as those for sows (5-10%). Otherwise. meat and
bone meal should be limited to 5-7% ofgrower and
gestation diets, 3-5% of lactation diets and 2% or
less in starter diets.
Additional Reading and References
Batterham, E.S., R.E. Darnell, L.S. Herbert and E.J.
Major. 1986. Effect ofpressure and temperature
on availability of lysine in meat and bone meal as
determined by slope-ratio assays with growing pigs,
rats, chicks, and by chemical assay. Brit. J. Nutr.
55:441-453.
Brooks, P. 1991. Meat and Bone meal: the under-
utilized raw material. Feedstuffs, volume 63,
number 27, 1991. pp. 13-15, 22.
Cromwell, G.L., T.S. Stahly and H.J. Monegue.
1991. Amino acid supplementation of meat meal in
lysine-fortified, corn-based diets for growing-
finishing pigs. J. Anim. Sci. 69:4898-4906.
Haugen, E.W. and J.E. Pettigrew. 1985. Apparent
digestibility ofamino acids in meat meal as affected
by manufacturing variables. Proc. 46th Minnesota
Nutr. Conf., Minnesota Agric. Expt. Stn., pp. 154-
169.
Knabe, D.A., D.C. LaRue and E.J. Gregg. 1987.
Apparent digestibility ofnitrogen and amino acids
in protein feedstuffs by growing pigs. J. Anirn. Sci.
67:441-458.
Leibholz, J. 1979. Meat meal in the diet ofthe
early-weaned pig. III. Meat meal quality and the
processing of meat meals. Anim. Feed Sci. Tech.
4:53-61.
Whole Milk
Whole cow's milk is usually not included in swine
rations because its value in human diets makes it too
expensive. However, it is perhaps nature's most
perfect feed and can be used very successfully in
swine rations. Milk provides more essential nutri-
ents than any other feed ingredient. Whole milk is
very easily digested and is extremely palatable. The
amino acid balance ofmilk protein is excellent and
because of its high protein quality, lower levels of
crude protein can be fed when using whole milk
than the levels commonly advised in feeding stand-
ards.
Milk provides energy in its milk fat and milk
sugar (lactose). It is an outstanding source of
calcium and a good source ofphosphorus. It is high
in vitamin A, rich in riboflavin and is a good source
of niacin, thiamine, vitamin B-12 and other B-
complex vitamins. However, it is not perfect. The
iron content is extremely low and it is a poor source
of vitamin D. Therefore, it is important that a
vitamin-mineral premix be utilized when whole
milk is being fed.
60

79. A nutritional breakdown of whole cow's milk is
shown below. Basically five pounds ofwhole milk
will supply the same amount ofnutrients as one
pound of complete feed.
Whole Milk
Digestible Energy 660
Crude Protein 3.50
Lysine 0.28
Digestible Threonine 0.13
Calcium 0.12
Phosphorus 0.09
An example of a feeding regime using whole milk
is shown in Table 4-5. Best use ofthe protein in
whole milk can be made if no other protein supple-
ment is used in the ration. However, since less dry
feed is to be fed, it is recommended that higher
levels ofvitamin-mineral premix be included in the
diet.
Table 4-5. Replacement Scheme for Using Whole
Milk in Swine Diets.
Weight of Meal Milk
Pig (kg) (kg) (Litres)
18 0.84 1.80
23 0.86 3.20
34 1.28 4.10
45 1.50 5.00
68 2.12 5.90
91 2.36 7.00
'Meal should contain 95% cereal grain and 5% vitamin-
mineral premix. Additional protein supplements are not
required.
Dried Skim Milk
Dried Skim Milk is ofcourse skim milk which
has had the water evaporated from it. The only
major difference between dried whole milk and
dried skim milk is that in skim milk, most ofthe fat
and fat soluble vitamins have been removed so that
all other components of the diet are increased
proportionally.
61
Dried Skim Milk
Digestible Energy 3850
Crude Protein 33.4
Lysine 2.43
Digestible Threonine I .31
Calcium 1 .20
Phosphorus l.00
Because ofprice, skim milk is not a commonly
used ingredient in swine diets. However, skim milk
may be diverted to animal feed ifexcess supplies
develop or ifa given shipment fails to meet certain
quality standards. Since these standards may relate
to factors of Little nutritional importance, a real
opportunity exists. However, ifthe milk powder
has been over-heated during drying, then its nutri-
tional value will be compromised.
Generally, even skim milk powder sold at distress
prices is economical only in creep and starter diets,
where it can make up to 20 - 30% ofthe total
formula. Pigs ofall ages can be fed skim milk.
Their feces may become loose as they adjust to the
lactose in the milk but this is usually a temporary
problem and will disappear in a few days. The
problem ofmilk intolerance in pigs tends to be
overestimated.
Additional Reading and References
Kornegay, E.T., H.R. Thomas and C.Y. Kramer.
1974. Evaluation ofprotein levels and milk prod-
ucts for pig starter diets. J. Anim. Sci. 39: 527-535.
Owsley W.F., D.E. Orr and L.F. Tribble. 1986.
Effects ofnitrogen and energy source on nutrient
digestibility in the young pig. J. Anim. Sci. 63: 492-
496.
Whey
When whole milk is treated with the enzyme
rennet, the protein casein is precipitated and takes
with it most ofthe fat and about halfof the calcium
and phosphorus. The remaining liquid is called
whey. Sweet whey arises from the production of
Swiss- or cheddar-type cheeses and acid whey from
cottage cheese production. About 9 kg of sweet
whey or 6 kg ofacid whey will be produced per

80. Photo 4-1.
The truth ofthe matter is that pigs can tolerate
lactose quite well. Research in Wisconsin demon-
strated that the pig can tolerate up to 30 % lactose in
its diet. Since whey is about 70-77 % lactose, this
translates into about 40 % whey in the diet on a dry
matter basis. Indeed. the scientists also learned that
removal of lactose from the diet of the older pig
will not diminish its ability to digest lactose in the
future. The pig's adaptability, in terms of diet, was
reaffirmed!
The major problem with feeding liquid whey to
swine is the high moisture content, and the pig's
inability to consume sufficient dry matter to grow
rapidly. Thus. care must be taken to ensure that
sufficient dry matter from other sources is provided
In older pigs, concern is often expressed about
their ability to utilize the lactose in whey. It is
known that as the pig ages, and no longer consumes
lactose, the special digestive enzyme called lactase,
that breaks down lactose in the gut, will decrease.
This is no surprise. since lactase is used solely to
degrade lactose, and if it is not present in the diet,
there is little reason for the gut to continue to
produce it. Consequently, farmers have become
reluctant to utilize whey in the diet ofgrowing or
finishing animals, even ifa local milk processing
plant can supply fresh whey at an economical price.
kilogram ofcheese. Sweet whey contains slightly
more crude protein ( 12 - 14 vs IO - 12%), more
lactose (68 - 72 vs 60 - 65%) and less ash (7.5 - 9.0
vs 9.5 - 1 l.5%) than acid whey. As its name im-
plies, it also contains less lactic acid (1.5 - 3.0 vs
5.5 - 7.5%). Whey contains almost all of the
lactose from milk and significant portions ofthe
mineral fraction as well. Since casein has been
removed, the major protein in whey is
lactoglobulin, which fortuitously is ofgood quality.
Lactose is desired in diets ofnewly weaned pigs,
due to its digestibility. However, some commercial
whey powders have had some ofthe lactose re-
moved so the content may vary from 35 to 58% of
the dry matter. As the amount of lactose increases,
the protein content decreases from 26 to 16%.
In its crude form, whey is a liquid; more than
90% of fresh whey is in fact water. Although liquid
whey can, and is, fed to swine, most has been dried
before inclusion in the diet. On a dry matter basis,
fresh whey is 70-77% lactose (milk sugar), 17%
crude protein, 9% ash (minerals), 1.0% calcium and
0.8% phosphorus. Although the true protein in
whey is ofgood quality, it must be recognized that
up to 25% of the nitrogen in whey is present as non-
protein nitrogen. Therefore, nitrogen assays tend to
overestimate the true protein content.
Typical diets for the early weaned pig contain IO -
20 % whey, while diets for pigs 5 weeks of age and
older will contain perhaps 5 - 10 % whey. Al-
though the presence ofwhey in such diets is desir-
able, nutrient composition must be considered to
ensure maximal performance. The addition of
whey alone to a diet cannot be considered sufficient Wet-Dry Feeder.
to maximize growth rate and feed efficiency.
Dried whey is generally used in the diet ofearly
weaned pigs, as a source ofhighly digestible lactose
and protein. However, excessive utilization of
whey can lead to diarrhea; the exact amount will
depend on other factors in the diet. Generally,
starter diets will contain no more than 15 - 20 %
whey, if for no other reason than cost. Concerns
about scouring often lead nutritionists to use skim
milk powder rather than exceed 20 % whey in the
diet. Again, cost becomes a limiting factor in such
diets, since skim milk powder is also very expen-
sive.
62

81. to pigs to support normal growth. If liquid whey is
being fed to pigs, the dry feed can be adjusted to
contain less protein and more mineral:vitamin
premix. Since whey is rich m protein. less supple-
mental protein would be required in the dry feed.
The premix must be increased since the pigs would
cat fewer kilograms of dry feed per day. but their
daily requirement would remain the same. The
exact adjustment would depend on the amount of
whey being eaten. Since the final ration, including
proportions ofwhey. grain and premix will vary
depending on pig size and amount of whey con-
sumed, a qualified nutritionist should be involved in
setting up feeding programs on individual farms.
Liquid feeding systems, in which the dry feed and
water are mixed prior to feeding, offer considerable
potential for liquid whey feeding. Also, wet-dry
feeders have been used for the same purpose.
Additional Reading and References
Ekstrom, K.E., N.J. Benevenga and R.H. Grurnmer.
1975. Effects of various dietary levels of dried
whey on the performance ofgrowing pigs. 1. Nutr.
105: 846-850.
Forsum, E. 1975. Whey proteins for food and feed
supplement. In Protein Nutritional Quality ofFoods
and feeds (M. Friedman, ed.). pp. 433-470. Marcel
Dekker. Inc.. New York.
Kornegay. E.T., H.R. Thomas and C.Y. Kramer.
1974. Evaluation of protein levels and milk prod-
ucts for pig starter diets. J. Anim. Sci. 39: 527-535.
Owsley W.F., D.E. Orr and L.F. Tribble. 1986.
Effects of nitrogen and energy source on nutrient
digestibility in the young pig. J. Anim. Sci. 63:492-
496.
Schingoethe, D.J. 1976. Whey utilization in
animal feeding: A summary and evaluation. J.
Dairy Sci. 59: 556-570.
Plant Sources
Feeds derived from plants tend to be relatively
uniform in composition within species. This helps
avoid the variability problems associated with feeds
derived from animal sources. I lowever, ingredients
derived from plant sources have other problems
which ma) limit their inclusion in swine diets. For
example. unprocessed oats arc too low in energy to
be utilized as a major constituent in most swine
diets. Barley, although higher in energy than oats. is
of limited value to nursing sows and baby piglets if
maximum performance is to be recognized. Some
plant products contain anti-nutritional factors that
impair digestion. reduce appetite, or may compro-
mise the health ofthe pig.
Alfalfa
There are problems associated with alfalfa
(Medicago sativa) which limit its usefulness as a
feedstuff for pigs. The protein and energy are
poorly digested and it contains toxic factors such as
saponins and tannins which reduce growth rates of
animals fed diets containing alfalfa. However.
despite the negative factors present, there is still
interest in the use ofalfalfa as a component of
swine diets and research continues to attempt to
overcome these problems. If this work is success-
ful, the use ofalfalfa in swine diets may increase.
Alfalfa Meal
Digestible Energy 1850
Crude Protein 17.0
Lysine 0.76
Digestible Lysine 0.36
Digestible Threonine 0.34
Digestible Tryptophan 0.10
Calcium 1.33
Phosphorus 0.23
The nutritional quality ofalfalfa varies with stage
of maturity, soil fertility. variety, physical handling
and other factors. The most significant factor
affecting the nutritional value ofalfalfa is the stage
ofgrowth at which it is cut. As the forage becomes
more mature, it contains less protein and more fibre.
Because ofthis variation in nutrient content, pro-
ducers arc advised to submit samples for laboratory
analysis before including alfalfa in any diet.
63

82. The primary factor limiting the use ofalfalfa in
swine diets is its low digestible energy content. The
crude fibre content ofalfalfa is extremely high
compared with grains and oilseeds. Since the pig
has a simple stomach of relatively small capacity, it
is less able to utilize crude fibre than are other types
of farm livestock. Therefore, the digestible energy
content ofalfalfa is approximately halfofthat
found in common cereal grains.
Alfalfa ranges from 12 - 22% crude protein (N x
6.25). Unfortunately, the protein in alfalfa is not
very digestible. The high crude fibre content of
alfalfa prevents the digestive enzymes from gaining
access to the soluble cellular proteins. As a result,
the protein in alfalfa is only about 50% digestible.
Alfalfa contains a good balance of amino acids and
a reasonable level of lysine. However, because of
the high fibre level, the availability ofthe lysine in
alfalfa is likely to be low.
Alfalfa is characteristically high in calcium.
However, it has only a moderate phosphorus con-
tent. When grown on phosphorus-deficient soils, it
may be very low in phosphorus. Therefore, rations
containing high levels ofalfalfa require supplemen-
tal phosphorus to meet the pig's requirement and to
narrow the wide calcium:phosphorus ratio present
in this forage. Alfalfa is a good source of most
vitamins and is an excellent source ofvitamins A, E
and K. However, the advent of relatively cheap
sources ofthese nutrients added via the premix has
resulted in a reduction in the need for alfalfa in the
diet as a source of vitamins.
Alfalfa should not be used in diets fed to wean-
ling pigs. Its high crude fibre content and low
digestible energy level are likely to limit growth and
reduce the efficiency offeed utilization when fed to
pigs of this weight range. Higher energy feedstuffs
should be used as the foundation for a high quality
starter diet.
It is recommended that no more than 5% alfalfa
be included in the diet ofgrower pigs. The data in
Table 4-6 illustrate the adverse effects of alfalfa
meal when included in the diet of market hogs. The
reduction in gain would appear to be the result of
insufficient dietary energy to meet requirements for
maximum growth.
Table 4-6. Growth, Feed Intake and Carcass Charac-
teristics of Pigs (54 to 100 kg) Fed Alfalfa.
� DietaQ:'. Alfalf�
Criteria 0.0 20.0 40.0 60.0
Daily Gain (kg/day) 0.86 0.73 0.63 0.41
Daily Intake (kg/day) 3.0 3.0 3.2 2.7
Feed/Gain 3.6 4.1 5.0 6.7
Dressing (%) 77.9 76.2 75.4 75.2
Backfat Thickness (cm) 3.9 3.5 3.2 2.9
Powley et al., 1981, J. Anim. Sci. 53: 308-316.
Poor palatability is one factor accounting for the
reduction in performance when high levels of
alfalfa are included in the diet ofthe growing pig.
Saponins are a bitter tasting compound present in
alfalfa. Recently, cultivars ofalfalfa varying in
saponin content have been developed. It would
appear that cultivars containing lower levels of
saponins are more palatable and support higher
levels ofperformance than do the traditional alfalfa
varieties. Future research may allow for higher
levels ofalfalfa to be incorporated into swine diets.
However, at the present time, it is not possible to
justify the use ofhigh levels ofalfalfa meal.
The subject of whether or not it is beneficial to
include alfalfa in diets fed to sows is controversial.
While some studies have supported its use, the
benefits can often be attributed to the vitamin E and
selenium supplied by the alfalfa meal. Since
synthetic sources ofboth vitamin E and selenium
are available, there does not appear to be any
necessity for the inclusion of alfalfa in gestation
diets. If it must be used, it would seem wise to limit
the levels of alfalfa fed during gestation to a maxi-
mum of25 - 30% of the diet.
Alfalfa meal should not be fed to sows during
lactation. Feeding alfalfa meal during lactation will
reduce the energy intake of sows resulting in re-
duced milk production. However, some producers
include bulky ingredients such as alfalfa meal in the
diets of sows during prefarrowing and early lacta-
tion to prevent constipation. ffthis is the case,
higher levels ofwheat or fat are needed to maintain
a high energy content.
64

83. In summary, alfalfa meal should not be included
in diets fed to starter and grower pigs and lactating
sows because of its high crude fibre content and low
digestible energy level. In rations fed to the gestat-
ing sow, a maximum of 25 - 30% of the diet is
suggested.
Additional Reading and References
Baker, D.H., B.G. Harmon and A.H. Jensen. 1974.
Value ofalfalfa meal and wheat bran in diets for
swine during prefarrowing and lactation. J. Anim.
Sci. 39:325-329.
Powley, J.S., P.R. Cheeke, D.C. England, I.P.
Davidson and WH. Kennick. 1981. Performance
ofgrowing finishing swine fed high levels ofalfalfa
meal: effect ofalfalfa level, dietary additives and
antibiotics. J. Anim. Sci. 53:308-316.
Thacker, P.A., 1990. Alfalfa meal. Pages 1-12 In
P.A. Thacker and R.N. Kirkwood eds. Non-tradi-
tional Feed Sources for Use in Swine Production.
Butterworths Publishers, Stoneham, MA.
Wallace, H.D., D.D. Thieu and G.E. Combs. 1975.
Alfalfa meal as a special bulky ingredient in the sow
diet. Feedstuffs (Feb 3). pp. 24.
Barley
Swine producers and feed manufacturers who arc
oriented towards com are sometimes unaware ofthe
wide use ofbarley (Hordeum vulgare) as a swine
feed and are often sceptical about its use. However,
barley is an excellent feed for swine and millions of
pigs are raised annually on barley-based diets.
Unfortunately, barley is notjust barley, There is a
tremendous amount ofvariability in the types of
barley available for use in swine production. Barley
can be either two-rowed or six-rowed, hulled or
hulless, awned or awnless. In addition, variation
exists among the lysine and starch content of
barleys. Even barley of the same genetic back-
ground can vary greatly since growing and harvest-
ing conditions can have profound effects on the
nutrient composition ofbarley.
For example, the results represented in Table 4-7
indicate that differences in growth rates and feed
efficiency between growing-finishing pigs fed
samples ofdifferent barley varieties can be as much
as 609%. The observed differences in animal
performance can largely be attributed to differences
Table 4-7. Composition of Barley Varieties and Performance of Growing-finishing pigs (approximately 20 to
95 kg body weight) Fed Various Barley Varieties*
Barley Variety
Boyer" Camelot" Clarkb Harrington" Hesk" Steptoe"
Chemical composition**
Dry matter, % 91.6 91.4 91.3 91.2 91.8 91.9
Crude Protein, % 9.4 13.2 10.2 11.0 9.1 9.9
Lysine,% .36 .44 .38 .42 .35 .36
Animal performance
Feed intake, kg/d 2.32 2.25 2.35 2.16 2.30 2.29
Growth rate, kg/d .78 .78 .80 .78 .79 .75
Feed: Gain 2.99 2.98 2.90 2.79 2.92 3.05
* The barley samples were supplemented with soybean meal and lysine to maintain similar lysine levels in all grower
(.75% lysine) and finisher (.60% lysine) diets and with vitamins and minerals. The inclusion levels ofthe barley
samples were 83.2 and 88.9% in the grower and finisher diet, respectively.
**As fed basis, analyses ofthe barley samples.
• Six-row winter barley varieties.
b Two-row spring varieties.
< Six-row spring variety.
Adapted from Michal et al., 1993. Washington State University Information Day Proc. Vol.8:69-74.
65

84. in unavailable energy content between the barley
samples that were evaluated. Small differences in
palatability (voluntary feed intake) were also
observed. ln this study, Harrington barley (a two-
row spring barley variety) supported the best feed
efficiency while Steptoe (a six-row spring barley
variety) results in the poorest growth rate and feed
efficiency. As only one sample ofeach barley
variety was evaluated, the differences in observed
levels of animal performance may have been due to
factors other than variety. For an estimation of the
feeding value of barley, producers are thus encour-
aged to have their barley tested before feeding it to
their pigs.
Barley is intermediate to wheat and oats as an
energy source for pigs. Its relatively high crude
fibre content (5.1%) is one of the major reasons for
the comparably low energy value. The digestible
energy (DE) content in individual barley samples
may be predicts from the dry matter and crude fibre
content:
DE (Kcal/kg of dry matter)= 4228 - 140 x Crude
fibre content(% in dry matter)."
The protein content ofbarley is intermediate to
that of wheat and com and similar to the level
contained in oats. Relative to requirements, barley
protein is generally low in lysine, isoleucine,
threonine, tryptophan and the sulfur containing
amino acids. The lysine content ofbarley is ap-
proximately equal to that ofwheat. The amino acid
content ofbarley can be predicted using regression
equations based on crude protein. These equations
can be found in chapter 3.
Barley
Digestible Energy 3100
Crude Protein 10.6
Lysine 0.39
Digestible Lysine 0.27
Digestible Threonine 0.23
Digestible Tryptophan 0.10
Calcium 0.07
Phosphorus 0.35
66
Because of its lower energy content, barley finds
only limited use in diets fed to starter pigs. How-
ever, when the cost ofother cereals is very high it
may be possible to include some barley in the diet
ofthe weanling pig. Only good quality barley
should be used. Barley can be fed very successfully
to growing pigs and in fact most pigs in Western
Canada are raised on barley. To maximize growth
rate, high energy cereals such as corn or wheat are
often used in combination with barley. Growth
rates in finishing pigs fed barley-based diets are
generally similar to these fed corn or wheat-based
diets. This is because finishing pigs are generally
able to compensate for reductions in diet DE
content with increases in daily feed intake in such a
manner that the daily energy intake is dependent on
diet DE content.
Barley can constitute the sole cereal grain in diets
fed to sows during gestation. However, because of
its lower energy content, it may be beneficial to
include between 25-75% wheat in the diet ofsows
during lactation.
The performance ofpigs fed barley-based diets
has been shown to be markedly improved as a result
ofpelleting. The reason for the improvement in
performance is a subject ofmuch debate. Some
researchers feel that the improvement is due to a
reduction in wastage, while others suggest that the
improvement is due to an increase in feed consump-
tion or to an increase in nutrient digestibility.
Barley that is frozen or sprouted sometimes
becomes available to the pork industry, and ques-
tions arise regarding its feeding value. Recent
studies carried out at the University ofAlberta
indicate that sprouting or frost damage will not
necessarily impair pig performance (Table 4-8). In
this report, bushel weight fell as low as 42 lb, but
all pigs performed equally, as compared to a control
diet based on normal barley.

85. Control Sprout
Frozen Frozen
Sprout
Frozen
Boyles, S.L., K.B. Koch. 1992. Feeding barley to
swine. ln: Feeding barley to cattle, swine and
poultry. North Dakota State University Extension
Services. North Dakota Sate University ofAgricul-
tural and Applied Science, Fargo, North Dakota.
Table 4-8. Utilization of Frozen or Sprouted Barley
(Bonanza) by Growing Pigs'·
Grain Analysis
Damage(%)
C. Protein (%)
C. Fibre(%)
Bushel Wt (lb)
Pig Performance
Ave. Daily Gain (kg)
Ave. Daily Feed (kg)
Feed Conversion
0.1 18.7 6.9
75 >75 >>75
12.1 13.3 11.0
11.4 11.7 12.2
6.5 7.3 7.3
7.4 7.9 9.0
51 48 45
47 42 43
0.71 0.72 0.70
0.71 0.70 0.69
2.27 2.24 2.23
2.18 2.22 2.29
1.59 1.61 1.56
1.56 1.56 1.58
Michal, J.J., M.S. Han and J.A. Froscth. 1993.
Nutrient composition and feeding value ofBoyer,
Camelot, Clark, Harrington, Hesk and Steptoe
Barley for growing-finishing pigs. Washington
State University Information Day Proceedings, Vol.
8 pp. 69-74.
Barley: High Moisture
Barley is traditionally harvested after it has been
field dried to a moisture content of 14-15%. This
drying is necessary in order to prevent deterioration
ofthe grain during storage. Spoiled grain is useless
as an animal feed since molds growing on the grain
may produce mycotoxins which cause poor growth
and reproductive problems.
Adapted from Plett, and Aheme, 1987. Proc. Western
Nutrition Conf. pp. 128-131.
I Barley represented 80% ofthe diet in all cases. Initial
pig weight averaged 20.8 kg; final weight was not
specified.
Additional References and References
Batterham, E.S. 1990. Prediction of the dietary
energy value ofdiets and raw materials for pigs. In:
(Wiseman, J. and DJ.A. Cole, Ed.) Feedstuff
evaluation. Butterworths, London, England, pp.
267-282.
Blair, R., B. Rakshit. J.M. Bell, V.J. Racz and K.A.
Rosaasen. 1990. Dietary energy level for growing-
finishing pigs fed ad libitum. 1. Growth response.
Arch. Anim. Nutr. 9:793-804.
Blair, R., B. Rakshit, J.M. Bell. VJ. Racz and K.A.
Rosaasen. 1990. Dietary energy level for growing-
finishing pigs ad libitum. 2. Carcass effects and
economical model of the responses. Arch. Anim.
Nutri. 9:805-813.
Grain drying systems have been developed which
allow crops to be harvested at higher than normal
moisture levels and then dried for storage. This
artificial drying requires a lot ofenergy. As energy
costs increase, it may become less attractive to
harvest grain in this manner. Therefore, producers
are looking for alternative harvesting methods. One
method that has generated considerable interest is
that ofharvesting high moisture grain.
High moisture grains are preserved in a manner
similar to silage. In the absence ofoxygen, acid
producing bacteria proliferate and produce acids by
fermenting barley sugars and carbohydrates. The
acids produced stop further bacterial action. The
ideal moisture content to ensile wet grain for swine
appears to be in the 22-28% range. A moisture
content greater than 28% leads to greater fermenta-
tion, resulting in more acid production which tends
to be less palatable to the pig. On the other hand,
the fermentation ofgrain containing less than 22%
moisture is relatively slow and the amount ofacid
produced may not be sufficient to kill those organ-
isms that cause spoilage.
67

86. A four-year research project conducted at Mon-
tana State University showed that high-moisture
barley could be harvested an average of 12 days
sooner than dry barley. By harvesting early, the risk
of losses due to high winds, rain, snow or frost is
minimized. Harvesting grain at a higher moisture
content also results in higher yields compared to
traditional harvesting methods. Field losses are
reduced because high-moisture barley does not
shatter like dry barley does. In the Montana State
University tests, high moisture barley yielded
16.7% more grain compared with similar fields
which were harvested as dry grain. In addition,
high moisture grain helped to control weeds, espe-
cially wild oats since reduced shattering resulted in
fewer weed seeds left in the field to germinate.
Although high moisture barley can be stored as
silage, several problems arise when it comes time to
feed the product. Since the grain contains moisture,
spoilage is always possible. Therefore, high mois-
ture grain must be fed soon after being taken from
storage. Untreated high moisture barley will heat
within hours of removal from the silo because of
microbial activity. Because ofthis, high moisture
barley diets must be mixed on a daily basis and in
amounts readily consumed over a short period of
time. Once a silo is opened, it is necessary to
remove approximately 7.5 cm per day from the
exposed surface of the silo to control spoilage. If
this does not match the daily feed requirements of
the pigs, some feed may be wasted.
Rates of acid application vary with the moisture
content ofthe grain and the intended length of
storage. The higher the moisture content ofthe
grain, the greater the amount ofacid needed for
proper preservation. Grain treated with an organic
acid should have a moisture content of22% or less
when harvested. A higher moisture level would
make the chemical treatment expensive to use.
The major disadvantage ofacid-treated grain is
the corrosive effect the acids have on most types of
metal in handling and storage equipment. The
corrosion is usually most severe on surfaces in
contact with the grain or vapour for the first weeks
following grain treatment. It may also react with
concrete, especially ifthe concrete is newly cured
and unweathered.
In terms ofchemical analysis, there is little
difference between high moisture barley and regular
barley on a dry matter basis (Table 4-9). High
moisture barley may be slightly higher in crude
fibre than regular barley since it loses less hull
during threshing. It may also be slightly higher in
protein content owing to the lighter and smaller
kernels saved by harvesting high moisture barley
which are slightly higher in protein but lower in
carbohydrate.
Table 4-9. Chemical Analysis of High Moisture and
Dry Barley.
A second alternative, treating grain with organic
acids, has kindled further interest in the use ofhigh
moisture grains. The application ofacid preserves
the grain by inhibiting mold growth. The acid
reduces the pH ofthe grain below the mold require-
ment and also kills the grain germ. Propionic,
acetic and formic acids are most common.
Composition High Moisture Dry
(%, in dry matter)
Protein 12.6 12.3
Ether Extract 2.2 1.9
Ash 3.0 2.7
Crude Fibre 6.4 4.9
Nitrogen Free Extract 70.7 71.1
The main advantage ofpreserving grain with
organic acid is the fact that the grain does not have to
be stored in the absence ofair. Therefore, existing
storage structures can be utilized. In addition, the
complete ground ration will not spoil in self feeders
and therefore, daily mixing is not required.
Adapted from Krall, 1972, Montana State Agric. Exper,
Station Bull. 625, pp 1-45.
There is evidence that carotene and vitamin E
activity are reduced in acid treated grains. How-
ever, phosphorus is more available in high moisture
grain compared with dry grain regardless ofthe
preservation method.
68

87. Table 4-10. Amount of High Moisture Grain Neces-
sary to Supply the Same Amount of Dry Matter as
Regular Barley (90% OM).
High moisture barley may be used effectively as a
feed grain. In formulating diets with high moisture
grain, adjustments must be made for excess water.
To convert wet grain to dry grain equivalent, divide
the dry matter content ofthe dry grain by the dry
matter content ofthe wet grain to establish an
adjustment factor. This factor will tell how much
more high moisture barley must be fed to supply
amounts of nutrients as dry barley on a dry matter
basis (Table 4-10).
% Moisture High Moisture Barley (kg)
Several reports have indicated that high moisture
barley may be more palatable than dry barley. This
improvement in palatability may be due to the fact
that high moisture grain is easier to roll and the
rolling results in a flaky product which contains
very little in the way offines or dust. This lack of
dust and fines in the ground product may be a factor
in improving palatability. However, in most in-
stances, when differences in dry matter are consid-
ered, consumption is about equal for high moisture
and dry barley. Since high-moisture grain has the
same feeding value as field dried grain when
compared on an equal dry matter basis, the decision
to use high-moisture grain should be made on the
basis ofcost, storage and handling and not on
clifferences in nutritional value.
15
20
25
30
35
40
45
1.06
1.12
1.20
1.28
1.38
1.50
1.64
Additional Reading and References
Weltzien, E.M. and F.X. Aheme. 1987. The effects
ofanaerobic storage and processing ofhigh mois-
ture barley on its ileal digestibility by, and perform-
ance of, growing swine. Can. J. Anim. Sci. 67:829-
840.
Adapted from Bowland and Corbet, 1973, Univ. Alberta-
52nd Ann. Feeders Day Report, pp 3-6.
Table 4-11. Performance and Carcass Characteristics
of Pigs Fed Acid-treated High Moisture Barley
(74.5% CM) or Regular Barley (85.8% OM).
On a dry matter basis, there is no difference in the
performance ofpigs fed high moisture or dry
barley. Average daily gain and feed conversion
efficiency do not cliffer between pigs fed dry versus
high moisture barley (Table 4-11).
Regular Acid-treated
Barley: Hulless
The performance ofpigs fed barley-based diets is
generally inferior to that ofpigs fed cliets based on
wheat or com. The major factors responsible for
the lower nutritional value of barley are its rela-
tively high crude fibre content and resulting low
energy level. However, since a large proportion of
the crude fibre content ofbarley is contained in the
hull fraction, it is possible that the removal of the
bull from barley could substantially improve its
nutritive value.
Gibson, D.M., J.J. Kenelly and F.X. Aheme. 1987.
The performance and tbiamin status ofpigs fed
sulphur dioxide treated high moisture barley. Can.
J. Anim. Sci. 67:841-854.
The huU ofbarley consists oftwo glumes, the
lemma and the palca, which completely enclose the
seed. ln traditional, hulled varieties of barley, the
glurnes are fused together and are attached to the
seed by a cementing substance produced by the
caryopsis. This causes the hull to remain attached
to the seed during harvest. Recently, cultivars of
barley have been developed in which the fusion of
2.09
0.69
3.02
78.80
3.55
100.00
2.18
0.69
3.15
79.00
3.35
103.00
Average Daily Feed (kg)
Average Daily Gain (kg)
Feed Conversion
Dressing Percentage
Carcass Backfat (cm)
Carcass grade
69

88. the glurnes does not occur, allowing the hull to be
removed during the threshing process in a manner
similar to that which occurs with wheat and many
other cereals. These so called hulless varieties of
barley would appear to have considerable potential
for use in swine rations.
ln general, hulless barley contains a higher protein
level and a lower crude fibre content than hulled
barley. All other nutrients are generally present at a
slightly higher level in hulless versus hulled barley.
This is to be expected when the diluting effect of
the hull is removed.
fibre, may in fact be higher in hulless barley as
compared to hulled barley. The beta glucan content
of barley is one of the factors that contributes to the
reduced feeding value of barley as compared to
wheat and com, especially in starter pigs.
For example, the results summarized in Table 4-
12 suggest that performance of starter pigs fed
hulless barley is similar to that in pigs fed regular
barley: pigs fed the hulless barley eat slightly less
and used feed slightly more efficiently that the pigs
fed the regular barley.
Table 4-12. Performance of Starter Pigs Fed Condor
Hulless or Samson Hulled Barley.
Barley: HuUess
DE
Crude Protein
Lysine
Calcium
Phosphorus
3250
13.7
0.54
0.24
0.37
Hulled Hulless
Barley Barley
Feed intake, kg/d 0.90 0.85
Growth rate, kg/d 0.59 0.58
Feed: Gain 1.57 1.47
Care must be taken when formulating diets using
hulless barley to balance for the amino acid lysine
rather than crude protein, since diet formulation on
the basis of the latter may result in an amino acid
deficiency. However, formulation on an amino acid
basis may require higher than normal crude protein
levels in the final diet in order to ensure that the
diets are balanced for lysine.
Unfortunately, the development ofhulless
cultivars ofbarley has not resulted in consistent
improvements in pig performance. Although
several researchers have indicated that the perform-
ance of pigs fed hulless barley is superior to that of
pigs fed hulled barley, other have observed little or
no improvement in performance. This may be
attributed to the actual samples ofgrains that were
evaluated, or the way in which experimental diets
were formulated, i.e. control ofthe proper lysine to
energy ratio. In most samples of hulless barley,
some hulls are still present. This is due to an
incomplete removal of the seed hulls during the
threshing process. The extent ofde-hulling should
thus be monitored via a visual inspection or fibre
analyses in the cereal grain sample. Another argu-
ment is that the content of beta glucan, a soluble
Thacker et al., I 987. University of Saskatchewan, Dept.
ofAnim. and Py. Sci. Research Reports, pp. 168-172.
Table 4-13. Performance of Growing-finishing Pigs
Fed Diets Based on Hulled or Hulless Barley.
Hulled Hulless
Feed intake, kg/d 2.46 2.32
Growth rate, kg/d .75 .74
Feed: Gain 3.30 3.13
Carcass dressingpercentage 80.6 79.8
Backfat, cm 3.5 3.5
Carcass index* 103.7 103.6
* Canadian carcass grading system
Adjusted from Thacker et al., 1988, Anim. Feed Sci.
Techn. 19: 191-196.
The result ofone experiment in which the hullcss
barley cultivar Scout was compared to the hulled
cultivar Harrington for growing pigs are presented
in Table 4-13. It can be seen that the average daily
gain and feed intake ofpigs fed the hulless barley
diet was not significantly different from that ofpigs
fed hulled barley. However, the feed conversion
efficiency of pigs given hulless barley was
70

89. significantly better than that of pigs given hulled
barley. This improvement in feed efficiency. in
combination with the lower levels ofsoybean meal
required in order to meet the pigs requirements for
essential amino acids, may provide sufficient
incentive to encourage the incorporation ofhulless
barley in swine diets, particularly when feed costs
are high. There is no data available on the feeding
value ofhulless barley for breeding swine.
However, given the benefits of increasing nutrient
density in nursing sow rations, serious consideration
should be given to the use of hulless barley in the
lactation diet.
Additional Reading and References
Aherne, F.X. 1990. Barley: Hulless. 1n: Non-
traditional Feed Sources for Use in Swine Produc-
tion. Butterworths Publishers, Stoneham, MA,
USA. (Thacker, P.A. and R.N. Kirkwood, Ed.).
Thacker. P.A., J.M. Bell, H.L. Classen. G.L.
Campbell, and B.G. Rossnagel. 1988. The nutri-
tive value ofhulless barley for swine. Anim. Feed
Sci. Tech. 19:191-196.
Beet Pulp
Beet pulp (Beta Vulgaris) is becoming a less
common ingredient in swine diets in Canada due to
changes in the sugar beet crop. Reduced availabil-
ity and consequent increases in the price have
forced nutritionists to seek alternative ingredients.
Beet pulp has proven to be a popular ingredient in
sow diets. It is often added to prevent constipation
problems. Five to seven percent beet pulp in sow
diets tends to solve all but the most challenging
cases ofconstipation.
It should be noted that the addition of beet pulp to
swine diets tends to reduce the digestibility of
energy and nitrogen. This is unlikely to be a practi-
cal problem, as only small quantities arc generally
used commercially.
Additional Reading and References
Graham, H., K. Hesselman and P. Aman. 1986.
The influence ofwheat bran and sugar-beet pulp on
the digestibility of dietary components in a cereal-
based diet. J. Nutr. 116:242 - 251.
Stebbens, H.R. 1991. The digestion and utilisation
of food fibre by growing pigs. Ph.D. Thesis,
University ofEdinburgh, UK.
Buckwheat
At the present time, buckwheat (Fagopyrum
sagittatum) is most commonly grown as a grain for
human consumption with small amounts used in
pancake mixes, breakfast cereals and in certain
breads and ethnic dishes. Buckwheat bas not been
widely utilized as a livestock feed although it now
appears that it has considerable potential for use as
an ingredient in swine diets.
Beet Pulp
DE
Crude Protein
Lysine
Calcium
Phosphorus
3000
9.9
0.60
0.70
0.37
71
Buckwheat
DE
Crude Protein
Calcium
Phosphorus
3010
11.2
0.08
0.32
Beet pulp achieved its greatest popularity as a
highly palatable soluble fibre source in the diet of
sows. It contains about 20% crude fibre, 24% acid
detergent fibre and 35% neutral detergent fibre.
However, the crude fibre portion tends to be more
digestible by swine than that ofstraw or oats.
Consequently, the digestible energy content of beet
pulp is about 86% of barley and 84% ofwheat.
Crude protein content is only about 10-12%. The protein quality ofbuckwheat is reported to be
among the highest in the plant kingdom. The
concentration ofseveral ofthe essential amino acids
is higher in buckwheat than any ofthe commonly
utiIized cereal grains. Ofparticular importance are
the levels of lysine and threonine which are the first
and second limiting amino acids in most cereal
grains. Buckwheat contains significantly higher
levels of both ofthese amino acids. Relative to the

90. requirements of the growing pig, buckwheat protein
contains adequate levels ofalmost all of the essen-
tial amino acids. Only isoleucine and methionine
are not present at a level greatly in excess of re-
quirement. Unfortunately, buckwheat supplies a
relatively low level of digestible energy (3000 kcal/
kg). The prime factors accounting for its low
energy content are a high crude fibre content
( 12.0%) and a low level of fat (2. l%). This low
digestible energy content is the prime factor limiting
the usefulness ofbuckwheat in swine diets.
containing a higher level of buckwheat tended to
have leaner carcasses in comparison with pigs fed
barley. Therefore, when prices dictate, buckwheat
can replace barley in rations fed to growing pigs.
Table 4-14. Performance of Growing Pigs (20-60 kg)
Fed Diets Containing Various Levels of Buckwheat in
Combination With Barley.
Percent ofCereal as Buckwheat
Anderson and Bowland, 1984. Can. J. Anim. Sci. 64:
985-995.
Farrell, D.J. 1978. A nutritional evaluation of
buckwheat tFagopyrum Esculentum). Anim. Feed
Sci. Technol. 3:95-108.
Thacker, P.A., D.M. Anderson and J.P. Bowland
1984. Buckwheat as a potential feed ingredient for
use in pig diets. Pig News and Information. 5:77-
81.
Thacker, P.A.• 1990. Buckwheat. Pages 61-68 In
P.A. Thacker and R.N. Kirkwood eds, Non-tradi-
tionaJ Feed Sources for Use in Swine Production.
Buttcrworths Publishers, Stoneham, MA.
100
0.70
2.01
2.91
27.50
7550
0.72 0.66
2.27 1.94
3.16 2.93
29.00 27.30
250
Daily Gain (kg) 0.70 0.70
Daily Feed (kg) 1.95 2.12
Feed/Gain 2.79 3.02
Backfat (mm) 30.90 31.10
Additional Reading and References
Anderson, D. M. and J.P. Bowland, 1984. Evalua-
tion ofbuckwheat (Fagopyrum esculentum) in diets
for growing pigs. Can. J. Anim. Sci. 64:985-995.
There is very little research conducted on the
feeding value ofbuckwheat for the breeding herd.
Based on its nutrient content, it is likely that buck-
wheat could be used in gestation diets. However,
buckwheat should not be used ifthe gestating sows
are housed outdoors. In addition, because ofits low
energy content, buckwheat should not be fed to
sows during lactation.
Another factor limiting the nutritional value of
buckwheat is the presence ofa photosensitizing
agent known as fagopyrin. Pigs fed high levels of
buckwheat develop peculiar eruptions and intense
itching of the skin when exposed to sunlight. This
condition is known as fagopyrism or buckwheat
poisoning. Only white or light-coloured areas of
the skin are affected and only ifthey are exposed to
direct sunIight. Ifanimals are kept indoors, away
from sunlight, they remain normaJ. Therefore,
under modern systems ofconfinement, fagopyrism
is unlikely to be a problem for pigs fed buckwheat.
Buckwheat also contains several other anti-
nutritional factors that may limit pig performance.
There is a trypsin inhibitor in buckwheat which may
decrease the digestibility of buckwheat protein. In
addition, condensed tannins are aJso present in
buckwheat but at a level considerably lower than
those found in sorghum or fababeans. Despite its
high quality protein, buckwheat should not be used
in diets fed to starter pigs. Its high crude fibre
content and low digestible energy level are likely to
limit growth and reduce the efficiency offeed
utilization when fed to pigs ofthis weight range.
Other alternatives arc available and producers
would be wise to choose a higher energy feedstuff
as the foundation for their starter diets.
The results ofa feeding trial in which buckwheat
was used to replace 0, 25, 50, 75 or 100% of the
cereal portion ofbarley-based grower diets is shown
in Table 4-14. Substitution of buckwheat for barley
had no significant effect on feed intake, daily gain
or feed efficiency. In addition, pigs fed diets
72

91. Canola Meal
Canola is a crop derived from rapeseed, but
developed by Canadian researchers to contain low
levels oferucic acid (< 2% of the oil) and
glueosinolates (<30 um/gin the meal). Previously,
these two constituents ofrapeseed meal had im-
paired its use in swine diets. The improved quality
ofcanola has elevated the crop to huge levels in
Canada, surpassing alI other export crops except
wheat; canola in its various forms - seed, oil and
meal - is now the second largest agricultural export
from Canada.
There are two types ofcanola currently grown:
Legend and AC Excel are commonly grown varie-
ties ofArgentine canola (Brassica napus), while
Reward and Parkland are varieties ofPolish canola
(Brassica rapa). Argentine cultivars of canola are
generally later maturing but higher yielding than
Polish varieties.
Canola meal is produced from the seed, following
a series ofprocesses designed to maximize the oil
yield; unlike the soybean industry, canola is still
driven by oil production as opposed to the meal.
During processing, the seed is first warmed to
prevent shattering, cleaned and then passed through
roller mills to produce a flake. The flakes are then
conditioned using heat and moisture to prepare
them for oil extraction, which occurs through a
series ofpre-pressing, mechanical extrusion and
finally hexane extraction. The solvent is then
removed from the meal using high temperature and
steam which also serve to ensure that myrosinase,
an enzyme involved in glucosinolate metabolism, is
denatured and thus rendered inactive. The meal
emerges free ofsolvent, with a moisture content of
8 - 10% and an oil content of less than l.5%.
Gums, a phospholipid by-product of oil extraction,
may be added back to the meal at this point.
since soybean meal contains 15% to 20% more
digestible energy.
Research on lowering the fibre content ofthe
meal could help to overcome the relatively low
energy concentration. Some breeding programs arc
selecting for reduced hull, as another way to
increase DE.
Research at the Prairie Swine Centre has revealed
that ifdiets are formulated on an equal nutrient
basis, canola meal will support performance
equivalent to that of soybean meal (Table 4-15).
Table 4-15. Performance of Female and Castrated
Male Pigs Fed Diets Containing Equal Levels of
Digestible Nutrients {based on either soybean meal,
or a combination of canola and soybean meals).
Canola Meal Soybean Meal
% Canola Meal 12.0 0.0
% Soybean Meal 8.3 16.1
Initial wt., kg 24.0 23.8
Final wt., kg 103.8 104.4
Ave. daily gain, kg 0.84 0.86
Ave. daily feed, kg 2.38 2.49
Feed conversion" 2.84 2.94
Carcass index 107.1 107.1
Lean yield, % 49.6 49.4
P2 backfat, mm 17.3 17.3
• Canola meal different from soybean meal, P < 0.05
Source: de Lange, J.F. Patience and 0. Gillis. l 993. ls
added biotin required in barley-based diets for growing -
finishing pigs? Prairie Swine Centre Annual Report. pp.
35 - 38.
Canola Meal
The greatest limitation to greater canola usage is
not palatability, although this unfortunately remains
a topic ofdiscussion. Countless experiments have
demonstrated the ability of the pig to consume
canola-based diets with little or no resistance -
provided the diets are properly balanced and pre-
sented to the pig. A relatively low energy level,
similar to that of barley, is a much greater problem,
73
DE
Crude Protein
Lysine
Digestible Lysine
Digestible Threonine
Digestible Tryptophan
Calcium
Phosphorus
3100
37.7
2.16
1.60
1.12
0.29
0.63
1.0 I

92. Unprocessed canola seed contains approximately
40% oil and 20% crude protein. Therefore, it can
be regarded as a high energy, relatively high protein
supplement. The level ofother nutrients are similar
to those found in canola meal modified only by the
dilution effect ofthe oil.
There is little information available on the
nutritional value ofwhole canola seed for starter
pigs. However, it would appear that the
performance of starter pigs may be enhanced as a
result of including whole canola seed in starter
diets. The results ofone feeding trial conducted at
the University ofAlberta are presented in Table
Canola Seed: Full Fat
Considerable interest has been shown recently in
the possibility of incorporating whole canola seed
into swine diets. Dry growing conditions, early
frosts and other weather conditions may result in the
production ofoff-grade canola seed which is
unsuitable for crushing or export. This seed can be
salvaged as a feed ingredient.
The addition offat to swine diets has been shown
to increase growth rates and improve feed conver-
sion efficiency for growing pigs. In addition. the
reproductive performance ofsows has been shown
to improve as a result of fat supplementation.
Unfortunately, there are many mechanical problems
associated with adding fats and oils to swine diets,
especially on farms using mix mills. However,
many ofthese problems can be overcome through
the use ofwhole canola seed as a fat source. Since
canola seeds are very small, a fine screen is re-
quired. The experience of some farmers indicates
that a 1/8" screen in good condition will result in a
reasonably good grind; some whole seeds may pass
through, but they represent a small portion ofthe
total.
FuU Fat
4750
20.7
1.20
0.39
0.64
Canola Seed:
DE
Crude Protein
Lysine
Calcium
Phosphorus
Several research trials conducted at various
institutions across Canada have shown that canola
meal can be used as part or all of the supplementary
protein in diets fed to breeding stock. Research
trials conducted at the University ofAlberta showed
no reduction in litter size, birth weight or weaning
weight when canola meal was fed to sows for two
successive parities. Therefore it would appear that
canola meal can be used as the sole source of
supplementary protein in diets fed to breeding
stock. Ifhigh energy lactation diets are desired,
extra fat will be needed to compensate for canola's
low energy content. However, care should be taken
to ensure that sows are gradually adapted to diets
containing canola meal and not replace all ofthe
soybean meal in the diet abruptly by canola meal.
Canola meal is complementary to other feedstuffs
used in swine diets and in particular, represents a
good "fit" with peas and other pulse crops. The
relatively higher sulphur amino acid content of
canola helps to offset the low TSAA content of
peas, while the high energy in peas counters the
lower DE value ofcanola meal. Because conditions
that favour the growing ofcanola are also desirable
for peas, the two crops represent an excellent
complementary pair from the perspective of both
swine nutrition and crop selection.
In summary, canola meal is a high quality product
and when properly utilized and priced competi-
tively, can reduce feed costs. Using typical feed
grain and protein supplement prices, canola meal is
competitive with soybean meal if it can be pur-
chased at about 65-75% ofthe cost of soybean meal
(47% protein) on a unit weight basis. When avail-
able at this price, even conservative nutritionists
should feel comfortable allowing canola meal to
provide 25% ofthe supplementary protein in starter
diets ( 18+ kg), 50% in grower and lactation diets
and 100% of the supplementary protein in finishing
and gestation diets.
Further Reading and References
Hickling, D. 1993. Canola meal: Feed industry
guide. Canola Council of Canada, Winnipeg. MB.
26 pp.
74

93. 4-16. This data indicates that the inclusion of 15%
canola seed resulted in improved growth and
increased efficiency. However, at higher levels of
inclusion, the palatability of the diet appeared to
decrease and as a consequence, performance
declined.
Table 4-16. Performance of Starter Pigs Fed Diets Containing Whole Canola Seed.
Average Daily Gain (g)
Average Daily Feed (g)
Feed Conversion
Control
498
638
1.28
15% Canela
512
649
1.26
30% Canola
415
615
1.48
Adapted from Shaw and Aherne, 1987, Univ. Alberta 66th Ann. Feeders Day Report. pp. 7-9.
The results ofa feeding trial in which whole
canola seed was included at 0, 3, 6. 9, 12 or 15% of
the diet of growing pigs are shown in Table 4-17.
In general, growth rates were improved at all levels
of inclusion but the optimum inclusion level ap-
peared to be about 6% of the diet. However, it may
be possible to include whole canola seed at levels of
up to 15% of the diet without any adverse effects
on pig performance.
It is important to note that the above experiment
utilized soybean meal as its source ofadditional
dietary protein. Addition ofa myrosinase source
such as whole canola seed to a diet containing
canola meal as the protein supplement could lead to
glucosinolate hydrolysis. This may result in a
reduction in performance. Therefore, it is recom-
mended that whole canola seed not exceed l0% of
the total diet ifcanola meal is present.
There does not appear to be any published infor-
mation on the effects of feeding whole canola seed
to breeding stock. Therefore, until more informa-
tion is available regarding the effects offeeding
whole canola seed on reproductive performance,
diets fed to pregnant or lactating sows should not
contain whole canola seed.
Table 4-17. Performance and Carcass Composition of Pigs Fed Diets Containing Whole Canola Seed.
Dietary Level ofCanola Seed(%)
0 3 6 9 12 15
Average Daily Gain (kg) 0.67 0.72 0.73 0.70 0.70 0.70
Average Daily Feed (kg) 2.09 2.17 2.10 2.19 2.03 2.04
Feed Conversion 3.11 3.01 2.87 3.12 2.90 2.91
Dressing Percentage 76.5 77.l 77. l 78.2 76.7 77.0
Carcass Grade 101.8 101.0 102.7 99.5 101.8 99.7
Backfat (cm) 3.2 3.2 2.9 3.4 3.0 3.3
Adapted from Castell and Falk, 1980. Can. J. Anim. Sci. 60:795-797.
75

94. Corn
Corn (Zea mays) sometimes referred to as maize
and related products have been popular ingredients
in swine diets for many years. Corn first became a
popular swine ingredient in Ontario when new
cultivars made it agronomically more feasible about
30 years ago. The high yields achieved in areas
capable ofgrowing com quickly translated into
more pounds of pork per acre than barley and the
switch to corn was thus inevitable. However, its
early introduction was met with a certain degree of
scepticism, due to concerns about carcass grades.
Proper diet formulation, and in particular maintain-
ing proper amino acid to energy ratios, soon over-
came such resistance. Pig diets based on com,
soybean meal and premix have become widely
accepted and have become standards against which
many alternative diets are compared. This does not
imply that corn (and soybean meal) based diets
should always be the diet ofchoice. In many parts
ofthe world, equivalent ofbetter performance is
achieved in pigs fed diets that contain feedstuffs
other than corn as compared to pigs fed corn based
diets. For example, starch in corn is not as well
digested by young, newly weaned piglets as the
starch in oats or barley. However, com is fed as the
main feed ingredient in diets for millions of pigs
and will continue to be a major feed ingredient in
the future.
Because of its high energy content, pigs perform
well on diets based on com. Carcass quality is not
impaired, as evidenced by the fact that average
carcass indexes in Ontario or Quebec, where com is
the predominant grain, are no poorer than those in
regions where corn is not used. The carcass fat
from pigs fed on corn will be different than the fat
ofpigs fed wheat or barley; it will be slightly softer
and perhaps yellower in colour. The softer consist-
ency reflects the content and quality of fat in com.
Corn contains approximately 3.5% fat which is
substantially higher than that in barley and wheat
that contain approximately 1.7% fat. The fat that is
present in com tends to be highly unsaturated and
soft (oily) as well; the colour is due to the presence
of a pigment called cryptoxanthin. In some parts of
the world, this colour is considered undesirable and
white varieties ofcorn are preferred.
76
Corn
DE 3550
Crude Protein 8.5
Lysine 0.26
Dig. Lysine 0.17
Dig. Threonine 0.21
Dig. Tryptophan 0.04
Calcium 0.02
Phosphorus 0.25
The protein content in corn is low and ofpoor
quality. Lysine and tryptophan are the first and
second limiting amino acids, respectively, for
swine. The reason for the poor quality of the
protein is that zein, the main storage form of
protein in the kernel, is a poor source ofmany
essential amino acids.
The amino acid content of com can be predicted
using regression equations based on crude protein.
These equations can be found in chapter 3.
Varieties ofcom that are higher in protein and
more specifically in lysine have been bred. The
lysine content in these varieties is approximately
30% higher than in conventional corn. The original
high lysine varieties, and in particular Opaque 2,
were not widely accepted because of poor agro-
nomic characteristics. such as yield and disease
resistance. However, more recently newer varieties
have been developed that have better yielding
characteristics. Commercial hybrids ofthese new
varieties will become available over the next few
years. In addition new varieties ofcorn with ex-
tremely high fat contents (up to 10%) may become
available in the future. The DE content ofthese
varieties may be as much as 10% higher than those
in conventional com.
Perhaps the greatest concern surrounding the use
ofcorn in swine diets is its susceptibility to molds,
especially when wet weather arrives during critical
growing stages. The actual mold does not appear to
be the problem; the fungi may consume some
nutrients in the kernel, but the effect on feed quality
is questionable. Corn so moldy that the kernels
could hardly be separated, has been fed to pigs with

95. no adverse affects on performance. However, when
the mold produces a mycotoxin, such as vomitoxin
or searalenone, the effects on swine can be very
serious. Reproductive performance of sows appears
to be most susceptible, so that some pork producers
have switched to barley-based diets for the breeding
herd. This is not necessarily a practical solution,
since barley can also be infected, and lactation diets
based solely on barley as the basal grain may
contain insufficient energy to support maximum
milk production.
If a suspected outbreak of mycotoxicosis occurs,
there is reason to believe that an increase in the
nutrient (energy, protein and vitamin) content ofthe
diet will be beneficial. Minimize other stressors in
the environment also since the pig is less capable of
dealing with them. A broad spectrum antibiotic at
therapeutic levels is recommended for the same
reason. The best course ofaction is to remove the
suspect feed until a proper analysis has been carried
out to determine if mycotoxicosis is the cause of the
problem. A variety offeed additives are currently
being evaluated as potential treatments for
mycotoxicosis. A more thorough discussion on
mycotoxins appears in chapter 11.
Com normally must be artificially dried to pre-
vent deterioration during storage or stored as a wet
grain, either treated with a preservative or held in an
oxygen limiting structure. Drying ofcom must be
carefully controlled to prevent loss ofnutritive
value. Research has shown that drying com at
temperatures of up to 110°C to a final moisture
content of 12-15% will have no effect on pig
performance. Exceeding l 50°C drying temperature
will reduce acceptability to the pig.
On a dry matter basis, there is little difference in
the nutritive value ofhigh moisture or dry corn.
Phosphorus is more available from high moisture
corn. As vitamin E tends to degrade faster in high
moisture corn than in dry com, higher fortification
with vitamin E may be required in high moisture
corn based diets. Otherwise, the decision ofwhich
storage method to use will depend on the relative
costs and convenience ofthe two systems. For
more information on high moisture cereal grains see
"high moisture barley" earlier in this chapter.
As with other cereal grains, variation in the
feeding value of different samples of corn, due to
differences in variety, growing, harvesting, and
drying conditions can be expected. It is, however,
surprising how little research has been conducted to
determine variation in feeding value of different
samples of(sub-standard) corn. Based on research
with chickens, which are more sensitive to changes
in feeding value than pigs, it can be concluded that
com bushel weight is a poor indicator offeeding
value of individual com samples. This is supported
by the observations made on starter pigs (Table 4-
18). These results suggest that some samples of
immature dried com with an extremely low bushel
weight can support levels ofperformance similar to
that in pigs fed regular com. Unlike in barley and
wheat. fibre levels in com are generally low and do
not vary much between samples. Fibre is thus also
a poor predictor of feeding value ofcorn samples.
The best predictor offeeding value may be the
starch content. In high fat com varieties, the fat
content should be considered as well. In regular
com. the starch content is approximately 60%,
while it may be as low as 50% in some samples of
com. Based on the French and Dutch net energy
Table 4-18. Nutritional Value of Immature Corn (different bulk density) for Starter Pigs Fed Corn-Soybean
Meal Based Diets.
Bulk density (lbs/bu) Gain (kg/day) Feed intake (kg/day) Feed efficiency
Control 1 * 57.4 .55 1.32 2.40
Control 2** 58.7 .57 1.42 2.49
Variety A# 50.6 .59 l.38 2.34
Variety B# 43.7 .60 1.41 2.35
Variety C# 43.6 .48 1.24 2.58
Variety D# 45.7 .51 1.23 2.41
* 1991 Ontario harvest; ** 1992 Indiana harvest; #immature dried com harvested between Dec 4, 1994 and Jan. 12,
1993. Adapted from Patterson et al., 1993, J. Anim. Sci. 71 (supplement I): 157 (abstract).
77

96. systems it could be derived that the DE content will
be reduced by 20 Kcal/kg per percent reduction in
starch content. This relationship should be con-
firmed in well controlled studies. As mentioned
earlier, the amino acid content ofdifferent corn
samples may be predicted from the amino acid
content.
Additional Reading and References
Patterson, R.. J.K. Tuitoek and L.G. Young. 1993.
Nutritional value of immature corn ofdifferent bulk
density for young pigs. J. Anim. Sci. 17 (supple-
ment 1 ): 157 (abstract).
Corn gluten feed consists primarily ofthe corn
hull mixed with some com germ. Due to its high
fibre and low energy content, poor amino acid
balance and digestibility it is more favoured in
cattle rations than in swine rations. lt contains
approximately 23% protein, 64% lysine and 3000
Kcal DE per kg. If included in swine diets the
inclusion level should be less than 5% in starter and
nursing sow diets and 20% in growing finishing pig
diets. Com gluten feed has been successfully used
at high inclusion levels in dry sow diets.
Corn Gluten Meal
Burgoon, K.G., J.A. Hansen, D.A. Knabe and A.J.
Bockholt. 1992. Nutritional value ofquality
protein maize for starter and finisher swine. J.
Anim. Sci. 70:811-817.
Adams, K.L. and A.H. Jensen. 1987. High-fat
maize for pigs and sows. Anim. Feed Sci. Techn.
17:201-212.
Corn By-Products
While the major portion ofthe com crop is
destined for use in livestock feeds, some is destined
for furtherprocessing. Three industries use corn as
raw material: the wet millers who produce starch
and oil for human use, the dry millers who produce
grits, meal and flour, and the fermentation industry.
In all cases, between 25 and 35% of the com used
this way will be returned in processed form to the
livestock industry as feed ingredients.
Com gluten feed and meal are by-products of the
wet milling industry. During wet milling, the raw
corn is soaked or steeped to soften the kernel and
facilitate separation ofgluten, protein and germ.
Steep water may be collected and sold as animal
feed. It is rich in protein and B-vitamins. The
steeped corn is then de-germinated (removes the
germ which may be sold as com germ meal); all
that is remaining at this point is the starch, gluten
and hulls. The hulls are removed and the residual
centrifuged to separate starch from gluten. The
corn starch is destined for the human food trade
while the gluten is used as animal feed. For every
I 00 kg of com milled, there will be 62-68 kg of
starch, 3 kg ofoil and the remainder will be corn
gluten meal. corn gluten feed and corn germ meal.
78
DE
Crude Protein
Lysine
Calcium
Phosphorus
4150
60.0
l.03
0.06
0.38
Corn gluten meal can be used in the diet of
market hogs or sows at levels of20-30% ofthe diet
without affecting palatability or performance,
assuming proper adjustments for nutrient composi-
tion are made. Indeed, higher levels are possible
with careful ration formulation. Com gluten feed
will be used to a much lesser extent it at all, due to
its lower energy content.
Com distillers dried grains are derived from the
fermentation industry, the most prominent ofwhich
is the alcohol industry. Actually two by-products
are made available to the livestock industry: com
distillers dried grains with solubles and com distill-
ers dried grains. Over the last years the production
has changed from primarily distillers (dried) grain
to distillers (dried) grain mixed with solubles. Both
Corn gluten meal is actually two products, con-
taining either 41 or 60% crude protein. The former
is generally a mixture ofthe 60% material and corn
gluten feed. Thus, the 41% meal is lower in energy
as well as protein compared to the 60% meal.
Compared to corn, 60% protein com gluten meal is
richer in energy and crude protein. However, like
the parent material, the balance ofamino acids is
poor with lysine and tryptophan being most limit-
mg.

97. of these products contain approximately 27% crude
protein. Although both can be used effectively by
the swine industry, the majority is destined for use
in cattle rations because the type ofprotein is
particularly attractive to high producing animals
especially dairy cattle. An additional concern with
using distillers grains, as in many by-products, is
the variability in the product. For example, in a
recent survey ofonly eight samples ofdistillers
dried grains with solubles, the lysine content varied
between .43 and 90% Odour and colour seem to be
important in determining the feeding value; light
coloured samples that are free ofburnt or smoky
odour, are more likely to have good nutritional
properties. Tnclusion levels of distillers dried grain
with solubles of up to 5% in starter diets, 20% in
grower-finisher diets and 40% in dry sow diets
appear to have little effect on animal performance
when diets are properly formulated and when good
quality products are used.
The energy content ofdistillers dried grains with
solubles is approximately equal to that ofcorn.
Like the parent material, the amino acid profile of
the protein is not well suited to the pig and thus
needs to be used in concert with a good quality
protein supplement. Although calcium and phos-
phorus levels are higher than corn, the differences
are ofonly marginal economic benefit.
Additional Reading and References
Cromwell, G.L., K.L. Herkelman and T.S. Stahly.
1992. Physical, chemical and nutritional characteris-
tics ofdistillers dried grains with solubles for chicks
and pigs. J. Anim. Sci. 71 :679-686.
Holden, P.J. 1991. Corn gluten feed. In (Thacker,
P.A. and R.N. Kirkwood, Ed.): Non-traditional
feed sources for use in swine production.
Butterworths Publishers, 80 Montvale Avenue,
Stoneham, MA 02180, U.S.A., pp. 131-138.
ComDistillers Grain
DE
Crude Protein
Lysine
Calcium
Phosphorus
3450
27.6
0.79
0.12
0.65
Newland, H.W. and D.C. Mahan. 199 l. Distillers
by-products. In (Thacker, P.A. and R.N. Kirkwood,
Ed.): Non-traditional feed sources for use in swine
production. Butterworths Publishers, 80 Montvale
Avenue, Stoneham, MA 02180, U.S.A., pp. 161-
173.
Table 4-19. Effect of Bushel Weight on Rate and Efficiency ofGrowth and on Digestibility of Energy in Corn.
Relative Change1
Corn Bushel Weight Rate of Gain Feed Efficiency Digestible Energy
Alberta
60 (100) 100 100 100
56 (93) 103 99 101
55 (92) 96 99 99
54 (90) 100 99 99
54 (90) 97 99 97
Manitoba
59 (100) 100 100 100
58 (98) 96 IOI 101
58 (98) 99 99 99
57 (97) 99 100 9
53 (90) 98 99 100
I
Comparisons were carried out by arbitrarily setting the values for the highest bushel weight at I 00 and calculating
each parameter as a percentage ofthe highest bushel weight sample. Thus, in an Alberta sample, the 56 lb corn had a
bushel weight that was 93% ofthe highest sample, but birds grew 103% as fast as the birds on the heaviest corn, they
converted the feed at 99% that ofbirds on the heaviest corn, and had a DE value of IO I% that of the heaviest corn.
Adapted from Campbell, 1981, Proc. Western Nutr. Conf. pp 238-242.
79

98. Dried Bakery Product
Dried bakery product, as its name suggests, is
reclaimed waste from bakeries. Because it has been
cooked during the manufacturing of the original
baked goods, this product is an excellent ingredient
for swine, especially for young pigs whose diges-
tive abilities are not yet fully developed. The
cooking degrades the starches and renders them
more available to the pig resulting in fewer prob-
lems with digestive upset.
However, because dried bakery product represents
waste materials, it often lacks uniformity; its con-
tents reflect the materials manufactured at the time
and place of collection. This lack ofuniformity has
compromised interest by the swine industry. Also,
since many bakery products are rich in salt, the by-
products also contain a lot of salt. Excess salt is not
desirable in the diet of young pigs. Many bakery
products are also sweet, so dried bakery products
tend to be highly palatable.
Dried Bakery Product
DE 3975
Crude Protein I 0.0
Calcium O.15
Phosphorus 0.25
If it can be purchased at a good price and its
nutrient composition can be characterized with
reasonable accuracy, dried bakery product offers
considerable opportunity in swine rations. Levels
of up to 30-40% of the diet would not be consid-
ered excessive, providing salt does not become too
high and assuming the material has been properly
analysed with respect to nutrient composition.
Because ofcost, dried bakery product is best used
in starter diets.
but like most legume seeds, it is deficient in
methionine. A high level ofcystine partly over-
comes the methionine deficiency and therefore,
supplementation ofdiets containing fababeans with
synthetic methionine has not proven to be benefi-
cial. The balance ofother amino acids appears fine.
Fababeans have a digestible energy content
between that of soybean meal and barley. The fat
content of fababeans is low ( 1.5%), which partially
accounts for its lower digestible energy. Fababean
oil contains a high content of unsaturated fatty acids
which can lead to the early development ofrancid-
ity after the seed has been ground. Therefore,
processed fababeans should not be stored more than
a week before use. The relatively high crude fibre
content of fababeans (8%) can also account for its
lower digestible energy content.
Fababeans are a relatively poor source ofcalcium
and are low in iron and manganese. In fact, extra
supplementation ofmanganese is required ifa diet
contains a large proportion offababeans. The
vitamin content ofthe fababean is lower than that
found in soybean meal or canola meal and there-
fore, diets containing a high level offababeans may
require a specially formulated premix in order to
supply a balanced ration.
Fababeans contain a relatively high level of
trypsin inhibitor although the level oftrypsin
inhibitor in fababeans is lower than the level found
in raw soybeans. The presence ofthis trypsin
inhibitor may cause a reduction in the digestibility
of protein in diets containing fababeans. However,
the level oftrypsin inhibitor can be reduced by
autoclaving (steam heating under pressure)
fababeans at 120°c for 30 minutes.
Fababeans
Fababeans (Viciafaba) arc an annual belonging to
the legume family and are related to the garden
broad bean. Initially most of the crop was grown
for silage, but in recent years more than 75% of the
crop has been grown for grain. The average crude
protein content of fababeans is approximately 24 -
30%. Fababean protein is relatively high in lysine
80
Fababeans
DE
Crude Protein
Lysine
Calcium
Phosphorus
3150
26.7
1.62
0.12
0.49

99. Another undesirable factor is hemagglutinin
which has been found to be present in fababeans at
a level of 2900 to 4200 rabbit RBC units per gram.
The corresponding values for soybeans, wheat and
barley are 650, 50 and 5 units. Autoclaving at
l 20°C has also been shown to reduce the activity of
the hemagglutinins in fababeans.
Fababeans contain between 0.3 and 0.5% tannin.
The presence ofthese tannins may lead to a reduc-
tion in feed intake when high levels offababeans
are fed to swine. In addition, the digestibility of
protein and energy may be reduced as a result ofthe
presence ofthese tannins.
As a result ofthe anti-nutritional factors present in
fababeans, it is recommended that fababeans not be
used to supply 100% ofthe supplementary protein
required to provide a balanced diet for swine.
Although there has not been a great deaJ ofresearch
conducted to determine the value ofincluding
fababeans in starter pig diets, the few reports
available suggest that fababeans should not be
included at a level in excess of 15% ofthe diet
(Table 4-20). At higher inclusion levels, there
appears to be problems with palatability and as a
consequence ofthe lower feed intake, growth rates
are impaired.
The effects ofincluding fababeans in breeding
stock diets has received little attention. However,
Danish workers have reported a significant reduc-
tion in litter size both at birth and weaning when
fababeans are included at high levels in gestation
diets (Table 4-22). Milk protein content and yield
have also been reported to be reduced when
fababeans are included at high levels in lactation
diets. Caution should also be exercised when
feeding fababeans to pregnant sows as fababeans
generate stomach gases and may cause constipation.
For these reasons, fababeans should not be used at
levels greater than 15% in diets for breeding stock.
Table 4-21. Performance of Grower Pigs (16-45 kg)
Fed Diets Containing Fababeans.
Fababean Level(%)
0 10 15 20 25 30
Daily Gain (kg) 0.68 0.66 0.65 0.65 0.61 0.58
Feed Intake (kg) 1.87 1.94 1.89 1.90 I.98 1.95
Feed/Gain 2.75 2.92 2.89 2.94 3.25 3.40
_Aheme et al., 1977, Can. J. Anim. Sci. 57: 321-328.
Table 4-22. Effect ofFababeans on Reproductive
Performance.
Table 4-20. Performance of Starter Pigs (10-25 kg)
Fed Graded Levels ofFababeans.
0
Fababeans (%)
17 34
0 10 15 20 25
Pigs Born Alive 12.0 10.5 9.7
Birth Weight (kg) 1.4 1.4 1.4
Pigs Weaned (8 weeks) 9.2 8.3 8.1
Weaning Weight (kg) 19.1 19.0 19.6
Milk Yield (kg/day) 6.3 5.5 5.2
Dry Matter (%) 19.0 18.9 18.6
Protein(%) 7.1 7.0 6.5
Fat(%) 5.5 5.6 5.7
Aheme et al. 1977, Can. J. Anim. Sci. 57: 321-328.
Daily Gain (kg) 0.55 0.54 0.54 0.48 0.51
Daily Feed (kg) 1.27 1.24 1.20 1.11 1.17
Feed Conversion 2.31 2.31 2.22 2.31 2.30
Level ofFababean (%)
The adverse effects of including high levels of
fababeans in the diet ofthe growing pig are clearly
demonstrated by the results of a feeding trial con-
ducted at the University ofAlberta (Table 4-21).
As the level of fababeans in the diet increased, daily
gain and feed conversion efficiency decreased. The
decrease in performance was particularly evident at
levels of inclusion greater than 20% of the diet.
Nielsen and Kruse, 1973, Livest. Prod. Sci. I: 179-185.
In summary, fababeans have much to offer as a
protein supplement and a considerable reduction in
feed costs may be achieved by their inclusion in the
diet. However, inclusion at too high a level will
impair animal performance. It is recommended that
fababeans not be included at levels greater than
15% in starter diets, 20% in grower diets and 15%
in diets fed to breeding stock.
81

100. Additional Reading and References
Aherne, F.X., A.J. Lewis and R.T. Hardin. 1977.
An evaluation of fababeans as a protein supplement
for swine. Can. J. Anim. Sci. 57:321-328.
Jansrnan, A.J.M., Huisman, J. and van der Poel,
A.F.B., 1993. lleal and faecal digestibility in piglets
offield beans tViciafaba L.) varying in tannin
content. Anim. Feed Sci. Tech. 42: 83-96.
Nielsen, I-1.E. and P.E. Kruse. 1974. Effects of
dietary horse beans ( Viciafaba) on colostrum and
milk composition and milk yield in sows. Livest.
Prod. Sci. 1: 179-185.
The fat content of field peas ( 1.2%) is low and
crude fibre levels in the field pea (5.8%) are ap-
proximately the same as those found in barley.
Field peas contain higher levels of both calcium
and phosphorus than the common cereal grains.
However, field peas are very deficient in vitamin E
and selenium and care should be taken to ensure
that the diet is supplemented with these two nutri-
ents when field peas are included at high levels in
swine diets.
Field Peas
DE 3400
Thacker, P.A., 1990. Fababeans. P.A. Thacker and
R.N. Kirkwood eds. Non-traditional Feed Sources
for Use in Swine Production. Butterworths Publish-
ers, Stoneham, MA. pp. 175-184.
Van der Poe), A.F.B., Gravendeel, S., vam Kleef
D.J., Jansman, A.J.M. and Kemp, B., 1992. Tan-
nin-containing faba beans tViciafaba L.): Effects
ofmethods ofprocessing on ileal digestibility of
protein and starch for growing pigs. Anim. Feed
Sci. Technol. 36: 205-214.
Field Peas
Field peas (Pisum sativum. arvense) are primarily
grown for human consumption and used mainly in
soup. Peas, or splits can be used quite effectively as
a livestock feed when available at a sufficiently low
price. In swine diets, field peas are most often
utilized to replace a portion ofthe protein supple-
ment but may also replace part of the cereal grain in
the diet.
At 22 - 29% crude protein, field peas are interme-
diate in protein content between cereal grains and
conventional protein sources. They are a good
source of lysine and appear to be adequate in all
other essential amino acids with the exception of
methionine and tryptophan,
The digestible energy content offield peas (ap-
proximately 3372 kcal/kg) is higher than most
commonly used feedstuffs. A high concentration of
easily digested starch is one ofthe major factors
accounting for this high digestible energy content.
Crude Protein 23.4
Lysine 1.50
Digestible Lysine 1.25
Digestible Threonine 0.62
Digestible Tryptophan 0.16
Calcium 0.09
Phosphorus O.50
Peas, like other pulse crops, contain some anti-
nutritional factors which will affect pig perform-
ance ifpresent at high enough levels. The presence
ofa trypsin inhibitor is likely the most important.
The trypsin inhibitor content ofspring seeded
varieties offield peas is generally between 2.3 and
5.5 TIA (trypsin inhibiting activity) units/mg DM
(dry matter) while winter varieties generally average
between 8.9 and 15.9 TIA units/mg DM. Field peas
are also reported to contain 80 units of
hemagglutinating activity and between 3.8 and 7.0
mg/kg ofcyanogenetic glycosides. Although these
anti-nutritional factors can be inactivated by heat,
they are usually not present at high enough levels to
reduce performance and therefore, are not generally
considered when formulating diets for swine.
There has not been a great deal of research con-
ducted to determine the value of including field
peas in starter pig diets. However, the few reports
available suggest that field peas can be included in
starter diets up to a level of 15% of the diet without
affecting performance. At higher levels of inclu-
sion, feed conversion starts to decline. Inadequate
tryptophan levels are suggested to be the cause of
82

101. Table 4-24. Performance of Growing-Finishing Pigs
(25-90 kg) Fed a Mixture of Peas and Canola Meal.
Canola Meal
2 Field Peas
Castell and Cliplef, 1993. Can. J. Anim. Sci. 73: I 29-
139.
Daily Gain (kg) 0.82 0.84 0.8 l 0.85 0.88
Daily Feed (kg) 2.32 2.44 2.38 2.53 2.62
Feed Efficiency 2.83 2.89 2.93 2.94 2.98
P2 Fat Depth
(mm) 11.7 11.9 12.2 11.7 12.5
Additional Reading and References
Abrahamsson, M., Graham, 11., Dandanell, D. and
Aman, P., 1993. Ilea! and faecal digestibility of
light or dark coloured peas (Pis11111 sativumi in
growing pigs. Anim. Feed. Sci. Technol. 42: 15-24.
P2
l/3P 2/3 P
2/3C 1/3 C
SBM C1
There is limited information on the effect of
feeding field peas to breeding stock. In one trial,
field peas were included at levels as high as 15% in
gestation diets and 25% in lactation diets without
affecting prolificacy or the number and weight of
weaned piglets. However, other trials have reported
reductions in litter size when a level of I 0% offield
peas was included in diets fed during gestation and
lactation. Therefore, until further work is con-
ducted, it may be wise to limit field peas to no more
than I 0% ofdiets fed to breeding stock.
In summary, field peas have much to offer as a
protein supplement and a considerable reduction in
feed costs may be achieved by including them in
swine diets. However, for best results it is recom-
mended that field peas not be used at levels higher
than 15% for starter pigs and l 0% for breeding
stock. For growing pigs, it would appear that field
peas can be used to completely replace the soybean
meal in the diet.
the reduction in performance. Therefore, careful
balancing of the diet for amino acids may permit
even higher levels ofinclusion.
Castell et al.. 1988. Can. J. Anim. Sci. 68: 577-579.
Table 4-23. Performance of Pigs (27-95 kg) Fed Peas
as a Replacement for Soybean Meal.
Level ofPea Substitution(%)
0 11 22 33
Daily Gain (kg) 0.88 0.89 0.83 0.86
Daily Intake (kg) 2.65 2.58 2.59 2.55
Feed Efficiency 3.01 2.90 3.12 2.96
Back.fat (mm) 16. l 15.5 15.7 15.2
There is much more data available on the effect of
including field peas in the diet ofgrowing pigs.
The results ofa feeding trial conducted at the
Agriculture Canada Research Station in Brandon in
which the performance of pigs fed a control diet
containing 12.3% soybean meal as the protein
supplement was compared with that ofpigs fed
diets containing peas at 11, 22 or 33% of the diet
are shown in Table 4-23. Pigs fed diets containing
field peas gained as well as those fed the control
diet at all levels of inclusion. No significant
changes were observed in carcass quality as a result
offeeding peas. Therefore, it would appear that
field peas can be used as the sole source of supple-
mentary protein in the diet ofgrowing pigs without
adversely affecting rate ofgain or feed efficiency.
There has been a considerable amount ofinterest
recently in the use of protein supplements made up
of a blend offield peas and canola meal. Canola
meal is a good source ofsulphur containing amino
acids while peas arc a superior source oflysine. As
a consequence, these two ingredients are particu-
larly compatible. Experimental evidence indicates
that the performance ofpigs fed a blend of these
two protein sources is superior to that ofpigs fed
either ingredient alone (Table 4-24).
Bell. J.M. and A.G. Wilson. 1970. An evaluation
of field peas as a protein and energy source for
swine rations. Can. J. Anim. Sci. 50: 15-23.
83

102. Castell, A.G. 1987. Field peas: an alternative
protein source for swine. Feedstuffs (Sept 7). pp.
16-17.
Castell, A.G., 1990. Field peas. Pages 185-197 In
P.A. Thacker and R.N. Kirkwood eds. Non-tradi-
tional Feed Sources for Use in Swine Production.
Butterworths Publishers, Stoneham, MA.
Castell, A.G. and Cliplef, R.L., 1993. Evaluation
of pea screenings and canola meal as a supplemen-
tary protein source in barley-based diets fed to
growing-finishing pigs. Can. J. Anim. Sci. 73: 129-
139.
Castell, A.G., Neden, L.R. and Mount, K., 1988.
Potential of field pea (Pisurn sativum) screenings as
feed for market pigs. Can. J. Anim. Sci. 68: 577-
579.
Fan, M.Z., Sauer, WC. and Jaikaran, S., 1994.
Amino acid and energy digestibility in peas (Pisurn
sativum) from white-flowered spring cultivars for
growing pigs. J. Sci. Food Agric. 64: 249-256.
Grosjean, F. and F. Gate!. 1986. Peas for pigs. Pig
News and 1nformation. 7:443-448.
Ogle, R.B. and Hakansson. 1988. Nordic research
with peas for pigs. Pig News and Information.
9:149-155.
Grain Dust
Grain dust is normally considered a nuisance
if not an outright health and safety hazard in
grain handling facilities. Yet, studies in the
United States suggest it is potentially a very
good ingredient, reflecting in nutrient composi-
tion, the parent material. The possible excep-
tions are fibre and ash which tend to be some-
what elevated relative to the parent grain. Grain
dust contains slightly more lysine than the
parent material. For example, wheat dust con-
tains 24% more lysine than the wheat it came
from. A summary of one study (Table 4-25)
illustrates the diffcrence between dust and
parent grains. One note of caution is the obser-
vation that considerable non-protein nitrogen
may be present in the dust so that crude protein
84
analysis may over-estimate the true feeding
value. Handling the product tends to be a major
frustration because it is bulky and not easily
conveyed by conventional grain handling equip-
ment. Lack of uniformity is also a concern.
Table 4-25. Comparison of the Composition of Grain
Dust and Parent Grains.
Wheat Corn Soybean
Nutrient Grain Dust Grain Dust Grain Dust
Moisture(%) 8.3 8.2 9.5 10.4 6.3 7.4
CP (%) 12.7 11.3 10.4 7.9 37.7 12.4
Ash(%) l.7 21.2 l.3 4.9 4.9 20.0
Adapted from Hubbard et al., 1982, Cereal Chem. 59:20-
22.
Contamination can also be a problem. Molds
may become associated with the dust from elevators
and other inadvertent contamination from various
chemicals and solvents used in the grain equipment
must be monitored. This may pose a health threat
not only to pigs eating it, but also to persons work-
ing in the barn and thus exposed to the dust.
Except for these very important concerns, grain
dust would appear to offer opportunities for feed
savings ifthe feed mill or farmer is willing to invest
some time and money in developing the expertise
required to formulate and manufacture appropriate
diets.
Grain Screenings
Grain screenings are not normally considered for
use in swine diets. The product is highly variable
and thus difficult to characterize sufficiently for
precise diet formulation. Since screenings are often
available at a very reasonable price, they should not
be ignored. However, they should be used with
caution.
There are a number ofclasses ofscreenings
available, generally from brokers or directly from
terminal elevators. Wheat screenings (No. 1 wheat
screenings, wheat feed screenings) are the best
quality ofscreenings available. They are obtained
from the cleaning ofwheat, and as such will often
contain considerable quantities ofbroken or small

103. wheat kernels. These are obviously quite satisfac-
tory for inclusion in swine diets. They will also
contain weed seeds such as wild buckwheat, wild
oats, cow cockle, lady's thumb, mustard and others.
Table 4-26 compares the chemical composition of
five samples of wheat screenings compared to a
sample of typical whole wheat.
Considering the origin of the product, wheat
screenings appear to be relatively consistent from
sample to sample and contain an excellent nutrient
profile. Crude protein and ether extract levels are
higher than wheat, while fibre on average is only
slightly higher than wheat. Thus, one would suspect
that such a material would have a digestible energy
content ofat least that ofwheat and probably 5%
higher. The gross amino acid composition is also
encouraging, with lysine, threonine and total sul-
phur amino acids (methionine plus cystine) above
that ofwheat. Since no estimate ofavailability was
given, one must be cautious in assigning available
amino acid levels any higher than those found in
wheat. Thus, ifthe product is palatable, it could be
used in the diet ofgrowing pigs and adult swine at
up to 40% ofthe total diet.
unless adjustment in other ingredients is made.
Their use would not normally be recommended in
the diets of lactating sows, weanlings or growing
pigs.
Table 4-26. Chemical Composition of Five Samples of
Feed Wheat Screenings Compared to Wheat.
Wheat Wheat Screenings
Typical Analysis Avg. S.D.1
Crude protein 12.20 13.60 0.90
Ether extract 1.60 5.30 1.70
Crude Fibre 2.60 3.40 0.70
Ash 1.40 2.20 0.20
Calcium 0.04 0.11 0.03
Phosphorus 0.31 0.37 0.02
Lysine 0.33 0.41 0.03
Threonine 0.28 0.36 0.02
Total Sulphur
Amino Acids 0.35 0.42 0.02
Grain Screenings
No. l Wheat
Grain screenings tend to be ofsomewhat lower
feeding value than wheat screenings. No. 1 grain
screenings are of approximately the same feeding
value as barley. Canola screenings, consisting of
only about 10% whole canola with the remainder
chaff, dust and weed seeds, is inferior to barley.
Digestibility studies suggest cano1a screenings have
about 60% of the feeding value of barley. Mixed
feed oats are in essence wild oats (86% oftotal) and
are ofonly slightly better value than rapeseed
screenings. Refuse screenings are about equal to
mixed feed oats.
In summary, the better quality screenings (No. I
wheat screenings and No. I feed screenings) can be
used in swine diets, provided palatability concerns
related to noxious weed seeds can be addressed.
No. I wheat screenings are approximately equiva-
lent to wheat and No. L feed screenings are approxi-
mately equal to barley in terms ofenergy and
perhaps slightly better in terms ofamino acids. The
use ofother screenings in swine diets will lead to
reduced performance due to lower energy content
85
DE
Crude Protein
Lysine
Calcium
Phosphorus
Grain Screenings
No. L Feed Wheat
DE
Crude Protein
Lysine
Calcium
Phosphorus
3250
12.9
0.37
0.04
0.32
3100
11.2
0.39
0.07
0.29

104. Lentils
Lentils (Lens culinarisy are a pulse crop suited to
cool temperate regions, exhibiting only moderate
resistance to drought or high temperature. The
major varieties grown in western Canada are Laird
and Esten. Lentils are grown for sale to the human
food market but on occasion, become available at a
competitive price to pork producers due to market
conditions or as a result of frost damage, seed
damage or aschocyta blight. Discoloration during
storage is also a concern, since it results in reduced
grades. Tannins, concentrated in the seed coat,
oxidize as the seed ages in storage causing the seed
coats to darken. It is advised that lentils be stored at
a moisture content no higher than 16% to prevent
deterioration during storage. If drying is required,
temperatures should not exceed 43°C.
Lentils are a very acceptable feedstuff for swine.
Even if slightly frost damaged and infested with
aschocyta, incorporation into diets at 30% will
cause no problems provided they are properly
formulated with respect to energy and essential
amino acid content (particularly methionine). On
the basis limited research, it appears that aschocyta-
infestation of lentils has little ifany adverse effect
on pig performance or health.
Table 4-27. Effects of Feeding Cull Lentils on Digest-
ibility and Pig Performance (23-100 kg).
Content ofLentils(%)
0 10 20 30
Apparent Digestibility (%)
Bell and Keith, 1986 Can. J. Anim. Sci. 66: 529-536.
Castell, A.G. 1990. Lentils. Pages 205-212 /n
P.A. Thacker and R.N. Kirkwood eds. Non-tradi-
tional Feed Sources for Use in Swine Production.
Butterworth Pub., Stoneham, MA.
Additional Reading and References
Bell, J.M. and M.O. Keith. 1986. Nutritional and
monetary evaluation ofdamaged lentils for growing
pigs and effects ofantibiotic supplements. Can. J.
Anim. Sci. 66:529-536.
Performance (23 to 100 kg)
79
79
76
0.86
2.58
3.00
78
78
75
0.86
2.56
2.98
79
80
78
79
80
78
0.82 0.83
2.53 2.48
3.09 2.99
Dry Matter
Energy
Nitrogen
Daily Gain (kg)
Daily Intake (kg)
Feed Efficiency
The chemical composition of lentils is influenced
by the cultivar seeded and the growing conditions
prior to harvesting. The crude protein content of
lentils (25.7%) is intermediate to cereals and
soybeans. Like all pulse crops, lentils are a rela-
tively poor source ofsulphur amino acids but are
rich in lysine. Care must be taken in swine rations,
especially those for the young pig, to ensure that
sulphur containing amino acids are not deficient.
About 7% of lentil protein is non-protein nitrogen
and the percent nitrogen in protein is 5.72%. Raw
lentils contain trypsin and chymotrypsin inhibitors,
although it appears that these are ofa sufficiently
low concentration to offer no difficulties when fed
to swine at up to 30% ofthe total diet. The lipid
content is not high, but is rich in linoleic acid, an
essential fatty acid in the diet ofthe pig. This may
be particularly important in areas where coarse
grains such as wheat and barley are fed. since they
contain much Jess Jinoleic acid than diets based on
corn.
Lentils
DE
Crude Protein
Lysine
Calcium
Phosphorus
3065
24.6
1.63
0.08
0.33
Castell, A.G. and Cliplef, R.L., 1990. Methionine
supplementation ofbarley diets containing lentils
(Lens culinaris) or soybean meal: Live performance
and carcass responses by gilts fed ad libitum. Can.
J. Anim. Sci. 70: 329-332.
86

105. Molasses - Beet
DE
Crude Protein
Calcium
Phosphorus
2475
7.1
0.10
0.02
lysine, threonine and the sulfur containing amino
acids. However, in contrast to most cereal grains,
selection for an increase in protein content will not
decrease protein quality. In this regard, oats are
unique among cereal grains since the lysine level of
grain is not inversely related to its protein content.
Oats contain approximately l 0% less digestible
energy than barley and about 20% less energy than
wheat and com. The main reason for the reduction
in energy content is the fact that oats contain almost
11 % crude fibre. This fibre is not digestible by the
pig and its presence also impairs the digestibility of
other nutrients contained in the grain.
Oats contain almost twice as much fat as barley
and wheat. This fat is distributed throughout the
endosperm, germ and aleurone layer ofthe oat
kernel with very little fat present in the pericarp
(outer layer). Oats also contain a very active lipase
(fat splitting enzyme) which is present almost
entirely in the pericarp of the oat kernel. Fortu-
nately, the enzyme does not normally come in
contact with the fat since this could lead to the
development ofrancidity. However, when the oat
kernel is broken or ground, the lipase in the pericarp
is brought into contact with the oat fat and free fatty
acids are released. As a consequence, ground oats
are far more likely to spoil than are other cereal
grains and care should be taken not to process them
too far in advance ofwhen they are required.
Typically, molasses contains about 22-25%
moisture. Energy content is about 12-15% less than
that of oats; therefore, use ofmolasses in swine
diets will reduce energy and crude protein content
unless other adjustments to the formula are made.
Molasses
Molasses is a by-product ofthe manufacturing of
sugar from either sugar cane or sugar beets. Thus,
molasses is often referred to as beet molasses or
cane molasses. Beet molasses is higher in crude
protein (7-11 % versus 3-4%) than cane molasses.
Beet molasses contain slightly more (4%) energy
than cane molasses but the latter tends to contain
more calcium (0.8-1.0% versus 0.1 %).
Molasses is becoming a much more difficult
product to obtain in adequate quantities at a com-
petitive price and thus is not generally used in swine
rations. There are exceptions, however. Some-
times, molasses will be used at a rate of 3-5% ofthe
diet for sows to help prevent constipation and
enhance feed intake. Other ways ofreducing
constipation are available, so using molasses will
depend on the personal preference ofthe farmer and
his nutritionist.
Oats
Oats (Avena sativa) are not widely utilized as an
energy source for use in swine production. The
main reason for their lack ofuse is the fact that they
contain a very high hull content which lowers their
digestibility and limits their nutritive value for
swine. However, when economics dictate, they may
find a place in diets fed to pigs during the various
stages ofthe production cycle.
Oats contain approximately 11.5% crude protein
(N x 6.25) and this protein is ofreasonably high
quality, having a better balance ofamino acids than
any of the other grains. They are still deficient in
87
Oats
DE
Crude Protein
Lysine
Digestible Lysine
Digestible Threonine
Digestible Tryptophan
Calcium
Phosphorus
2800
10.8
0.40
0.26
0.19
0.08
0.10
0.35

106. Since oats are low in energy, they are not recom-
mended as a good source ofcarbohydrate in starter
diets. For example, when oats replace corn at levels
between O and 50% (Table 4-28a) in diets fed to
pigs from 5 - l 8 kg, both growth rate and feed
conversion suffer. This reduction in performance
may reflect the pigs' inability to consume sufficient
oat diet to meet their energy requirements for
optimal growth. The gains are therefore slower and
less efficient.
The adverse effects of including oats in diets fed
to growing pigs are clearly demonstrated by the
results of the experiment presented in Table 4-28b.
It can be seen that as the level of oats in the diet
increases, average daily gains decrease and the
amount of feed required per pound of gain in-
creases. Clearly, ifany reasonable level of perform-
ance is desired, oats should not be included in
grower diets.
Table 4-28a. Effect of Substituting Oats for Com on the Performance ofWeaner Pigs.
Level ofOats (%)
0 10 20 30 40 50
Daily Gain (kg) 0.35 0.36 0.33 0.30 0.30 0.30
Daily Feed (kg) 0.68 0.68 0.67 0.67 0.61 0.64
Feed Conversion 1.94 l.89 2.03 2.10 2.03 2.13
Watts and Moser, 1981, Nebraska Swine Report. pp 5-6.
Table 4-28b. Effect of Substituting Oats for Corn on
Grower Pig Performance.
Level of Oats (%) 0 29 60 95
Daily Gain (kg) 0.80 0.70 0.63 0.57
Daily Intake (kg) 2.93 2.95 2.77 2.71
Feed Conversion 3.67 4.20 4.44 4.77
Jenson et al., 1959, J. Anim. Sci. 18: 701-709.
Oats may be successfully used in diets fed to
gestating sows. During gestation. it is recom-
mended that the energy intake ofsows be restricted.
Therefore, the lower energy content of oats is a
desirable feature. However, it is recommended that
oats constitute no more than 50% ofdiets fed to
sows during gestation. During lactation, oats
should not be fed at all.
Feeding oats may also be of value ifa swine
operation is experiencing problems with gastric
ulcers. Several experiments have suggested that
oats may have some value in protecting growing
pigs against ulcers. The protective effect ofthe oats
is believed to be due to an alcohol-soluble fraction
contained in the hulls.
Additional Reading and References
Anderson, D.M., J.M. Bell and G.l. Christison.
1978. Evaluation ofa high-protein cultivar ofoats
(hinoats) as a feed for swine. Can. J. Anim. Sci.
58:87-96.
Jenson, A.H., D.E. Becker and S.W. Terrill. 1959.
Oats as a replacement for com in complete mixed
rations for growing-finishing swine. J. Anim. Sci.
18:701-709.
Wahlstrom, R.C., L.J. Reiner and G.W. Libal.
1977. Oats, dehulled oats and hulless barley as
ingredients in pig starter diets. J. Anim. Sci.
45:948-952.
Watts, G. and B.D. Moser. 1981. Oats for early-
weaned pigs. Nebraska Swine Report. pp. 5-6.
88

107. Oats: Naked
Since the high fibre content ofoats is the major
factor detracting from its use as a livestock feed, a
considerable amount ofeffort has been extended to
try and reduce the crude fibre content ofoats. Plant
breeders in several countries have recently devel-
oped varieties ofnaked oats and these new cultivars
would appear to have considerable potential for use
in swine production. The most popular naked oat
currently available in Canada is the cultivar Tibor.
Table 4-29. Comparison of Naked Oats and Other
Cereal Grains as an Energy Source for Weane.- Pigs
(25 - 56 days).
Naked Oat Wheat Corn
Oats Flakes
Daily Gain (g) 381 434 472 433
Daily Intake (g) 575 625 651 601
Feed Conversion 1.51 1.44 1.38 1.39
Fowler, 1985, Pig Farming Suppl. pp 45-52.
Table 4-30. Performance of Market Hogs Fed Naked
Oats (32 - 79 kg).
Morris and Burrows, 1986, Can. J. Anim. Sci. 66:
833-836.
Several experiments conducted with naked oats
and growing pigs have almost completely removed
the supplementary protein from the diet without
significantly affecting performance. This implies
that the amino acid profile ofnaked oats is adequate
to meet the requirements ofthe growing pig. There-
fore, the potential exists for a substantial reduction
97
0.84
2.36
2.81
78.40
33.40
104
65
0.83
2.40
2.89
78.50
32.20
103
30
0.84
2.59
3.09
76.90
32.60
104
0
0.82
2.61
3.18
77.40
32.60
104
Daily Gain (kg)
Daily Intake (kg)
Feed Conversion
Dressing Percent
Backfat (mm)
Carcass Grade
Naked oats can be used with a high degree of
success in diets fed to growing pigs. The results of
one experiment in which naked oats were used to
replace 0, 30, 65 or 97% ofthe com and soybean
meal in diets fed to pigs from 32 - 98 kg are shown
in Table 4-30. It can be seen that growth rates were
similar at all rates ofinclusion while there was a
tendency for feed efficiency to be improved as the
level ofnaked oat in the diet increased. Dressing
percentage was slightly improved in the naked oat
diets but the carcasses tended to be fatter as the
level ofnaked oat in the diet increased.
Hulless oats are not really bulless. They do have
a hull but it is much more loosely attached than with
conventional oats and is blown away in the field
during combining. Therefore, the crude fibre
content ofhulless oats (2.7%) is much lower than
conventional oats (10.7%). As a consequence, the
digestible energy content ofhulless oats is much
higher than that ofconventional oats. In addition,
the oil content is also higher in hulless oats (7.5%
versus 4.7%) than conventional oats. Due to the
increase in oil, it is wise to supplement diets con-
taining naked oats with higher levels ofvitamin E to
avoid problems with rancidity.
Despite the improvement in the nutritional com-
position ofhulless oats, it would appear that they
still cannot be utilized as the sole cereal source in
diets fed to weaner pigs. The results ofan experi-
ment in which naked oats were compared with com
and wheat for pigs from 25 - 56 days ofage are
shown in Table 4-29. All diets were adjusted with
dried skim milk and fish meal so they provided
26% protein, 1.4% lysine and 17 MJ DE/kg. How-
ever, both daily gain and feed efficiency were
poorer for pigs fed the diets containing hulless oats.
The poorer performance for the weaner pigs fed
naked oats has been attributed to the presence ofa
high level ofbeta-glucan, a gummy polysaccharide
which interferes with digestion.
The crude protein content of hulless oats is also
higher than conventional oats. Hulless oats have a
good balance ofamino acids with lysine and
methionine being the only amino acids not present
in adequate amounts to meet the requirements.
Vitamins and minerals are generally present at a
slightly higher level than in conventional oats as a
result ofremoving the diluting effect ofthe hull.
89

108. in feed costs should naked oats be used at high
levels in swine diets.
Naked oats have been grown successfully in
Canada. However, in some years, the hulls were
not as effectively removed by combining as hoped.
Yields have also been disappointing at times. If the
agronomic problems can be resolved though, naked
oats should have an excellent future in swine diets.
Additional Reading and References
Christison, G.1. and J.M. Bell. 1980. Evaluation of
terra, a new cultivar of naked oats (avena nuda)
when fed to young pigs and chicks. Can. J. Anim.
Sci. 60: 465-471.
Fowler, V 1985. Naked oats, exciting new feed
for pigs. Pig Fanning supplement. November
1985. pp. 45-52.
Friend, D.W., A. Fortin. L.M. Poste, G. Butler, J.K.
Kramer and VD. Burrows. 1988. Feeding and
metabolism trials and assessment ofcarcass and
meat quality for growing-finishing pigs fed naked
oats. Can. J. Anim. Sci. 68:511-521.
Oat Groats
DE
Crude Protein
Lysine
Calcium
Phosphorus
3725
16.0
0.50
0.10
0.40
Oat Groats
Oat groats are obtained by mechanically dehulling
oats. The removal ofthe highly fibrous hull from the
oat seed greatly improves the nutritive value ofthe
resulting product. Oat groats are considered to be
one of the most palatable and easily digested
feedstuffs available for use in swine production.
The crude protein content ofoat groats is higher
than that ofunhulled oats as a result ofremoving
the diluting effect of the hull. The digestible energy
content ofoat groats is also 35 - 40% higher. The
protein quality of oat groats is considered to be
fairly high with lysine and threonine being the only
amino acids not present in sufficient amounts to
meet the requirements ofthe growing pig.
Friend, D.W., A. Fortin, L.M. Poste, G. Butler, J.K.
Kramer and V.D. Burrows. 1989. Naked oats
(Avena nuda) with and without lysine supplementa-
tion, for boars and barrows: Growth. carcass and
meat quality, energy and nitrogen metabolism. Can.
J. Anim. Sci. 69: 765-778.
Morris, J.R., 1990. Oats: Naked. Pages 275-284
In P.A. Thacker and R.N. Kirkwood eds.
Non-traditional Feed Sources for Use in Swine
Production. Butterworth Publishers, Stoneham,
MA.
Morris, J.R. and V.D. Burrows. 1986. Naked oats
in grower-finisher diets. Can. J. Anim. Sci.
66:833-836.
Myer, R.O., R.D. Barnett and W.R. Walker. 1985.
Evaluation of hulless oats in diets for young swine.
Nutr. Rept. lnt. 32: 1273-1277.
The major factors determining the use ofoat
groats in swine rations are cost and availability. It
takes almost 160 kg ofoats to produce 100 kg of
oat groats. When the initial purchase price ofoats
is combined with the cost ofdehulling, the selling
price demanded by oat groat manufacturers is
higher than can bejustified on the basis oftheir
nutrient content. Therefore, oat groats are generally
used only in the higher priced diets such as creep
feeds and starter diets. This will depend on local
conditions and the pricing policy ofsuppliers.
Potatoes and Potato Products
Potatoes (Solanum tuberosumy are grown prima-
rily for human consumption. However, surplus
potatoes, potatoes unfit for human consumption,
and potato by-products (from the production of
potato starch, french fries or potato chips) are
available for use as swine feed ingredients.
Fresh potatoes contain only about 20-22% dry
matter. Because potatoes are almost all starch, they
90

109. Potatoes can be used effectively in the diet of
pigs, although there are notable limitations. Raw
potatoes contain solanin, especially in the sprouts;
On a dry matter basis the feeding value ofcooked
potatoes is similar to that ofcereal grains. The
digestible energy is 3370Kcal/kg while the crude
protein content is I 0.9%.
are very high in energy but very low in crude
protein. More than halfofthe nitrogen present is in
the form of non-protein nitrogen and therefore is
not protein at all. Essentially then, potatoes are a
source of energy.
Potatoes are very low in magnesium. Since
magnesium is not usually supplemented in standard
swine diets, special attention should be paid to this
mineral to ensure it is not deficient (ie. Supplemen-
tation of the diet may be required).
this is believed to be partly responsible for the poor
digestibility and palatability of raw potatoes.
Cooking improves digestibility and removes factors
that inhibit digestive enzymes. However, the water
used for cooking should be discarded and not fed to
pigs because it contains the water-soluble solanin.
Cooked potatoes are an excellent energy source,
containing more energy than corn or wheat. The
digestibility ofgross energy in the pig is 96%
compared to 85%-88% for wheat and corn.
Some researchers have developed feeding regimes
for swine, allowing free choice access to cooked
potatoes and Limit-feeding a 19% protein concen-
trate at the rate ofabout 1.14 kg per pig per day.
Raw potatoes can only be fed to dry sows, where
6 kg ofpotato can replace 1 kg of barley with
additional protein supplementation. Raw potatoes
have been fed to finishing pigs, but when 25% of
dietary dry matter was supplied by potatoes, signifi-
cant reductions in performance were observed.
Cooked potatoes are accepted by all classes of
swine. However, due to the water content and its
high bulk it is not recommended for starter pigs.
Recommended maximum inclusion levels (dry
matter basis) are 30% for growing pigs. Recom-
mended maximum inclusion levels (dry matter
basis) are 30% for growing pigs., 50% for finishing
pigs and 25% and 50% for nursing and dry sows
respectively.
The two main potato by-products that could be
used as swine feed ingredients are potato steam peel
and potato chips. Potato steam peel is a by-product
ofpotato processing where the peel is removed after
processing. It contains typically 15% dry matter,
and 3400 Kcal/kg, 16% protein, and .05% lysine on
a dry matter basis. This product can be included at
up to 20% (dry matter basis) in grower-finisher pig
diets. Substandard potato chips will be high in
energy (typically 30% fat as they are cooked in oil;
DE content of 5250 kcal/kg) and low in protein
(typically 6.5% protein). It is a highly palatable
ingredient that can be included at levels up to 15%
in starter diets and 25% in diets for grower pigs, dry
and nursing sows. Because of the high fat content
and fat quality (oily) it is recommended that the
inclusion level in the finisher diet be restricted to
10% or less.
3350
7.7
0.40
l.20
0.85
Potatoes
DE
Crude Protein
Lysine
Calcium
Phosphorus
The crude protein content ofpotatoes are low.
More than halfof the nitrogen present is in the form
ofnon-protein nitrogen and therefore is not protein
at all. However, the actual protein that is present in
potatoes is ofan extremely high quality. Purified
potato protein is widely used in the human food
industry; its high price prohibits its use in diets for
(starter) pigs.
A major drawback with feeding fresh potatoes is
the low dry matter content (18 to 25%); when large
quantities are fed to pigs, bulkiness will limit
nutrient intake. In addition, raw potatoes contain
anti-nutritional factors (chymotrypsin inhibitors and
solanine; the latter in green potatoes in particular)
that make them unpalatable to pigs. Cooking or
steaming potatoes effectively inactivates these anti-
nutritional factors and at the same time enhances the
digestibility ofstarch.
91

110. Additional Reading and References
Edwards, S.A. and R.M. Livingstone. 1991. Potato
and potato by-products. In (Thacker, P.A. and R.N.
Kirkwood, Ed.): Non-traditional feed sources for
use in swine production. Butterworths Publishers,
80 Montvale Avenue, Stoneham, MA.
Van Lunen, T.A., D.M. Anderson, A.M. St-Laurant,
J.W.G. Nickelson and P.R. Dean. 1989. The
feeding value ofpotato steam peel for growing-
finishing pigs. Can. J. Anim. Sci. 69:225-234.
Rye
From an agronomic point ofview, rye (Secale
cereale) is an attractive crop for Western Canada. It
produces higher yields ofgrain than other cereals
particularly on poor quality, sandy soils, and assists
in better management ofthe soil by minimizing soil
erosion. Rye is traditionally sown in the fa!J mak-
ing more effective use ofwater during spring runoff
and allowing for a more equitable distribution ofa
farmer's workload due to its early harvest.
Unfortunately, the market for rye has been limited
due to several toxic factors which can reduce its
nutritional value. Ifthe detrimental effects ofthese
anti-nutritional factors could be overcome, it would
make available to the swine industry an alternative
feed resource from a previously little used product.
The energy level ofrye is intermediate to that of
wheat or barley, while the crude protein (N x 6.25)
content is similar to barley and oats but lower than
wheat. It supplies a reasonable balance of amino
acids and contains roughly the same amount of
lysine as barley or wheat. Relative to the require-
ments of the growing pig (20 - 50 kg), only lysine,
threonine and the sulfur containing amino acids are
not present in sufficient quantity to meet require-
ments. However, these total values must be inter-
preted with caution since the availability ofthe
amino acids in rye are approximately 5 - I 0% lower
than those in barley and wheat.
Rye supplies approximately the same amount of
calcium (0.06%) and phosphorus (0.32%) as other
cereals. A specialized premix should not be neces-
sary if rye is used as the major energy source in a
swine ration. The content ofother minerals and
vitamins would also appear to be similar to those
found in other cereals.
Rye is susceptible to contamination and infection
from several undesirable fungi, the most important
of which is ergot. Ergot may contain IO or more
toxic alkaloids including ergotamine, ergotoxine
and ergonovine (see Ch. 11 ). Although ergot has
been shown to reduce the performance ofpigs fed
rye, it is important to realize that ergot is a fungus
contaminating rye and not a factor inherent to the
rye itself. New varieties of rye have recently been
developed which are much more resistant to ergot
infestation. Examples ofthese ergot resistant
varieties are Puma, Musketeer, Cougar and Kodiak.
When these varieties are fed, ergot is far less likely
to be a problem than with the more traditional
cultivars ofrye.
Recent research has indicated that rye also con-
tains high levels ofsoluble pentosans and these
pentosans may pose a greater problem than the
presence ofergot. Pentosans are normal constitu-
ents ofthe cell wall and are related to hemicellulose
but are more soluble. They result in a highly
viscous intestinal fluid that interferes with digestion.
Another compound found in rye which was
believed to reduce pig performance is a fat-soluble,
growth inhibiting substance called 5-n-alkyl
resorcinol. However, the most recent work on rye
tends to discount the importance ofalkyl resorcinol
as a factor contributing to the poor performance of
pigs fed rye.
Most recommendations concerning the nutritional
value ofrye are based on the older varieties ofrye
which were often contaminated with ergot. These
recommendations may no longer be valid since
ergot is present at much lower levels in the newer
varieties ofrye. As a consequence, the potential to
use rye in swine diets may be greater than was
previously realized.
Rye is relatively unpalatable. Feed intakes of pigs
fed rye-based diets are generally 10% lower than
those ofpigs fed a barley-based diet. The specific
factor causing the reduced intake has not been
identified although a simple increase in the dusti-
92

111. ness of the ration has been implicated. Since
weaner pigs are often reluctant to eat solid feed, a
feedstuffof questionable palatability should not be
included in a starter diet. Therefore, it is suggested
that rye not be used in diets fed to starter pigs.
Rye would appear to have much more potential
for use in diets fed to growing pigs. The results of
one experiment in which grower pigs were fed
either a barley or a rye-based diet are shown in
Table 4-31. Pigs fed diets in which ergot-free rye
was utilized as the sole energy source in the diet
gained approximately 5% slower than did pigs fed a
barley based diet. However, it took significantly
less feed to put on a pound ofgain using the rye-
based diet. This improvement in feed efficiency
may provide sufficient incentive to encourage the
incorporation ofrye into swine diets, particularly
when the cost of other cereal grains is high.
The reduction in performance which occurs as a
result offeeding ergot-free rye has been attributed
to the presence of soluble pentosans. Supplementa-
tion ofdiets containing rye with an enzyme capable
ofbreaking down these pentosans has been shown
to produce a modest improvement in pig perform-
ance. As a consequence, there is not much differ-
ence in the performance ofpigs fed enzyme-
supplemented, rye-based diets and those fed barley.
Therefore, it would appear that when prices warrant,
enzyme- supplemented rye can be used as 100% of
the cereal portion ofa swine diet without a signifi-
cant reduction in pig performance.
There is very little information concerning the
feeding value of ergot-free rye in diets fed to
breeding stock. Until further research is conducted,
it may be wise to limit the inclusion of rye to no
more than 25% of the diet during gestation and to
avoid feeding rye to sows during lactation.
The nutritive value of rye for swine can be im-
proved by processing. Since dustiness is a problem
when rye is fed, producers are advised to utilize a
coarser grind(< 4 - Smm screen) when processing
rye for use in swine rations. Supplementation with
low levels of (0.5 to 2.0%) fat or vegetable oil may
also help to reduce the dustiness. In addition, the
nutritional value of rye for pigs has been shown to
be substantially improved by pelleting.
Additional Reading and References
Bazylo, R.B., 1990. Rye. Pages 363-372 In P.A.
Thacker and R.N. Kirkwood, eds. Non-traditional
Feed Sources for Use in Swine Production.
Butterworths Publishers, Stoneham, MA.
Thacker, P.A., G.L. Campbell and J. Grootwassink.
1991. The effect ofenzyme supplementation on the
nutritive value ofrye-based diets for swine. Can. J.
Anim. Sci. 71: 489-496.
Thacker, P.A., Campbell, G.L. and J. Grootwassink,
1992. Effect ofsalinomycin and enzyme supple-
mentation on nutrient digestibility and the perform-
ance of pigs fed barley- or rye-based diets. Can. J.
Anirn. Sci. 72: 117-125.
Average Daily Gain (kg) 0.79
Average Daily Feed (kg) 2.19
Feed Conversion 2.74
0.76
2.02
2.64
0.78
2.05
2.64
93
Soybeans: Full Fat
The soybean, a legume, is one of the oldest
cultivated crops known to mankind. But only over
the last 50 years has the potential ofsoybeans as a
source ofoil and protein in human and animal diets
been fully recognized. It is estimated that soybeans
account now for close to 80% of the supplemental
protein used in cereal grain based diets for non-
ruminants in North America. Although full-fat
soybeans and soybean meal are the main products
of interest to swine producers, recent developments
in further processing ofsoybean products have
resulted in the production of protein concentrates
(containing approximately 70% crude protein on a
dry matter basis) and isolates (containing approxi-
Thacker ct al., 1991. Can. J. Anim. Sci. 71: 489-496.
Table 4-31. Effect of Enzyme Supplementation on the
Performance of Growing Pigs (20-98 kg) Fed Rye.
Control Rye Rye
& Enzyme

112. matcly 70% crude protein on a dry matter basis)
and isolates (containing approximately 90% crude
protein on a dry matter basis). These products have
favourable nutritional characteristics. I lowever
given the high cost of these products, they should
only be considered for use in milk replacer or in
highly complex (pre-) starter diets.
Although commercial soybean meal manufactured
from raw soybeans by cooking and removal of the
oil represents by far the major product used in
swine diets, full fat beans are also used. With 18%
fat they provide more energy and are therefore
particularly desirable in the manufacture ofstarter
of lactation diets. For farmers mixing their own
diets, full fat beans offer a vehicle for adding fat to
high energy diets without investing in expensive fat
handling equipment. The use of full-fat soybeans
means that growers can feed the product on site
rather than selling the beans and buying back the
meal.
Heating raw soybeans helps to improve their nutritive
value by destroying anti-nutritional factors such as trypsin
inhibitor.
Soybeans: Full-fat
DE
Crude Protein
Lysine
Calcium
Phosphorus
4200
37.2
2.25
0.25
0.59
94
Fortunately, most of these ANF's can be
inactivated, and animal performance can be
improved when beans are heated prior to feeding.
However, soybeans can be overheated as well.
Excessive heat destroys various amino acids (in
particular lysine) and can thus also reduce the
feeding value offull-fat beans. Means to heat beans
include roasting, extruding, jet sploding (exposing
beans to heated air) and micronizing (using radiant
heat). Heating methods that can be considered on
the farm are roasting and extruding. During
roasting, beans should be heated between 3 and 5
minutes and the target temperature should be
approximately 120°C. When extruding, the target
exist temperature should be approximately 130°C.
It should be noted that these alternative heat
treatments are not equally effective and that the
effectiveness of heat treatment is determined by
many variables including: duration, temperature,
pressure during heating, rate ofcooling,
composition of the bean (moisture and oil) and
particle size. As a result, there can be considerable
variation in the feeding value ofheat treated
soybeans. For example, the data in Table 4-32
indicate that the DE content of roasted beans may
be as much as 12% lower than that in extruded full-
fat soybeans.
Raw soybeans contain various anti-nutritional
factors (ANF). The major ANF's are a group of
proteins called trypsin inhibitors, which interfere
with trypsin, a digestive enzyme produced by pigs.
Other ANF's in soybeans include hemagglutinis
(lectins), saponins and lipoxidase. Due to the
presence of these ANF's it is not recommended to
feed raw beans to most classes ofpigs. It depresses
growth and feed efficiency in growing pigs (starters,
growers and finishers). ln nursing sows it reduces
feed intake and as a result increases body weight
losses and reduces litter growth rates. Only dry
sows are able to perform well when fed raw beans.
Recently some varieties of soybeans have been
developed that contain lower levels ofsome of the
ANF's and that are superior in feeding value com-
pared to conventional beans. However, even when
these new varieties arc fed raw to starter and grower
pigs, animal performance is reduced.

113. Derived from Marty et al., Can. J. Anim. Sci. 73:411-
419.
Table 4-32. The Effect of Heat Treatment on the
Digestible Energy Content of Soybeans.
The inclusion ofheated full fat soybeans in starter
pig diets has not resulted in consistent improve-
ments in performance in comparison to soybean
meal based starter diets. In some studies, and in
If full-fat beans are to be used, one must consider
the extra energy supplied in the diet. Remember
that full-fat beans contain about 12% more energy
than high protein (dehulled) soybean meal. Failure
to maintain the proper ratio ofessential amino
acids, in particular lysine, to energy will result in
reduced growth rates, feed efficiency and in the case
offinishing pigs in reduced carcass lean yields.
particular when roasted full fat beans were used,
starter pig performance was in fact reduced when
heated full fat beans where fed. This may be the
result of incomplete inactivation ofANF's, or an
insufficient rupturing ofthe cells in the seed during
roasting. It should be noted that, given the immatu-
rity ofthe digestive system, starter pigs will be
more sensitive than any other class ofswine to
insufficient processing offull-fat soybeans. When
extruded beans are used to replace soybean meal in
starter pig diets, pig performance is generally
improved. Extruded beans can effectively replace
all ofthe soybean meal in starter pig diets.
In growing-finishing pig diets heated full fat
soybeans can supply all of the supplemental protein
in cereal grain based diets. Feeding roasted full fat
soybeans will result in slight improvement in
growth rate and feed efficiency as compared to
feeding soybean meal, but not to the same extent as
the feeding ofcereal grain, soybean meal and
supplemental fat (Table 4-33). Apparently roasted
beans are not equivalent to a mixture of soybean
meal and soybean oil, even for growing-finishing
pigs. A concern with using full fat soybeans as the
sole source ofsupplemental protein in finishing
diets is its effect on the content and quality ofthe
fat in the carcass. In particular, in pigs with
unimproved lean growth potential, and increase in
daily energy intake due to increases in dietary
energy density, may increase carcass fatness and
thus reduce lean yield. Carcass fat is certainly
softened when full fat soybeans are fed. This has
been associated with a paler colour of the meat and
in several instances, to a reduced acceptability by
the consumer of pork. The results ofsome studies
indicate that the inclusion level offull fat beans
should not exceed 10% in com-based finishing pig
diets in order to maintain pork quality. As barley
and wheat contain less fat than corn, this would be
equivalent to approximately 20% in barley or wheat
based diets.
5020
4780
4680
4420
DE content (MJ/kg dry matter)
Extruding
Jet sploding
Micronizing
Roasting
Heat treatment
A laboratory assay that can be used to routinely
check the adequacy of heat treatment of full fat
soybeans in the urease test. In this test the activity
ofurease, an enzyme that breaks down urea and that
is present in raw soybeans, is monitored. This
enzyme is a protein and is, just like the trypsin
inhibitors, inactivated when heat treated. The
urease activity, measured in change in pH (acidity)
in a standard solution should not exceed .20 units.
Unfortunately there is not yet an accepted procedure
that can be used to determine whether beans have
been over-heated. The most reliable method is still
an objective evaluation of colour and odour. The
heat treated product should be light in colour
(devoid of dark, burned particles) and small "nutty"
rather than burned.
95

114. Table 4-33. Performance of Growing-finishing Pigs
Fed Roasted Beans as the Sole Supplemental Protein
Source in Com-based Diets
* The amount of oil and soybean meal added to the diet
resulted in similar total protein and fat contents to that in
the roasted soybean meal based diet; derived from
Cromwell et al., 1990. J. Anim. Sci. 68 (suppl. 1 ): 112.
The advantage of including heat-treated full-fat
beans in sow diets appears quite similar to advan-
tages of alternative high energy sow diets (chapter
6). Due to their maturity, sows are better able to
utilize nutrients from full fat soybeans, even ifthey
are not heat treated properly.
SBM Roasted SBM
Soybeans and oil*
Soybean meal gained acceptance in part because it
complemented corn so well in the diet of the pig. It
is high in energy and is a rich source ofthe amino
�cids such as lysine and tryptophan that are lacking
in co1:1. The calcium content may vary among
suppliers from as low as 0.25% to over 1.00%, due
to the use of limestone in some cases to enhance its
flowability. This poses no particular problem
provided appropriate adjustments are made to the
overall formula to ensure that calcium.phosphorus
ratios in the final diet are maintained in the accept-
able range. Also, as limestone use rises, the con-
centration ofother nutrients such as amino acids
and energy will fall.
false perceptions about its quality. The presence of
anti-nutritional compounds covered in the previous
section focused attention on the soybean's limita-
tions rather than its potential. However, research
into the proper handling and utilization ofsoybeans
soon overcame the early problems. As a result,
soybean meal has been a staple in swine diets since
the 1940's..92
2.64
2.86
.89
2.76
3.10
.89
2.81
3.16
Daily gain (kg)
Daily intake (kg)
Feed conversion
Additional Reading and References
Marty, B.J. and E.R. Chavez. Effects ofheat
processing on digestible energy and other nutrient
digestibilities offull-fat soybeans fed to weaner,
grower and finisher pigs. Can. J. Anim. Sci.
73:411-419.
Herkelman, K.L. and G.L. Cromwell. 1991.
Utilization of full-fat soybeans by swine reviewed.
Feedstuffs. 62(52): 15-17, 22.
De Schutter, A.C. and J.R. Morris. 1991.
Soybeans: full-fat. ln: Non-traditional Feed
Sources for Use in Swine Production. Butterworths
Publishers, Stoneham, MA, U.S.A. (Thacker, P.A.
and R.N. Kirkwood, Ed.), pp 439-45 l.
Soybean Meal
Since soybean meal is now used so extensively in
swine diets, it is difficult to imagine that its early
introduction was fraught with problems due not
only to legitimate anti-nutritional factors but also
Soybean meal is produced from raw soybeans by
removing the oil and grinding the remaining flakes.
Different processes may be involved. The most
commonly used are pre-press solvent where oil is
literally squeezed from the seed before solvents are
added to remove the remaining fat, or solvent
extraction alone.
Two types of soybean meal are currently avail-
able: high protein or dehulJed and the lower pro-
tein, non-dehulled products. Dehulled meal con-
tains less hull and as a consequence, is richer in
protein, amino acids and energy than the meal
containing the hull. Because of their widely differ-
ing nutrient composition, it is important to define
which meal one is talking about. For example, the
protein content ofthe dehulled meal is about 47%
while that of the standard meal is 44.0%. Energy
levels are approximately 5% higher and lysine
about 10-15% higher in the dehulled product.
96

115. Sunflower meal has not gained the same degree of
prominence in swine diets as other protein meals,
reflecting not so much nutritional problems, but
rather the availability ofseed for crushing. It
appears to be readily accepted by pigs. From a
nutritional perspective, dehulled sunflower meal
represents a good product with considerable poten-
tial in swine diets.
Sunflower Meal
Sunflowers (Helianthus annuusy arc grown in
southern Manitoba, Saskatchewan and in the north-
ern Plains States ofthe U.S., in part for the oilseed
market and, to a lesser extent, the confectionary
market. The two are distinct in terms of the varie-
ties ofsunflowers grown. Confectionary sunflower
seeds will not be used for oil production.
the young piglet's digestive system. However, for
all other classes of swine a consistent and known
quality ofsoybean meal can support good levels of
animal performance if used as the sole source of
supplemental protein. In fact, choosing the amount
of soybean meal to use will depend mainly on price
and availability.
44%CP
3500
44.3
2.86
2.40
l.29
0.46
0.29
0.61
48%CP
3675
47.5
3.18
2.70
1.44
0.50
0.29
0.60
Soybean meals:
DE
Crude Protein
Lysine
Digestible Lysine
Digestible Threonine
Digestible Tryptophan
Calcium
Phosphorus
Soybean Meal:
DE
Crude Protein
Lysine
Digestible Lysine
Digestible Threonine
Digestible Tryptophan
Calcium
Phosphorus
The amino acid content ofsoybean meal can be
predicted using regression equations based on crude
protein. These equations can be found in chapter 3.
Three types ofsunflower meal are available.
DehuJled sunflower meal contains about 38% crude
protein; for swine, it is far superior to the standard
meal which generally contains less than 30% crude
protein and is very high in crude fibre. A third
product, partially dehulled sunflower meal, is
intermediate between the two. Jt contains about
32% crude protein. The fibre content varies dra-
matically between the three meal from about 14%
in the dehulled meal to 25 - 30% in the standard
meal. Consequently, the energy content of the
various sunflower meals varies widely. Even
dehulled sunflower meal has more than twice as
A variety oftests are available to evaluate the
quality ofsoybean meal. Moisture, protein and
calcium analyses are recommended to ensure that
guaranteed minimum (protein content) and maxi-
mum levels (hull and limestone content) are met
and to estimate amino acid content. The urease test
may be used to ensure that the anti-nutritional
factors in the soybean meal are sufficiently inacti-
vated (see previous section on full-fat soybeans).
Residual hexane content may also be tested. An
objective evaluation ofcolour will provide a reason-
able indication ofproduct quality as well. A darker
quality suggest that the protein quality is reduced
and that further laboratory tests may be required
(amino acid analyses; protein solubility in potas-
sium hydroxide).
Soybean meal is often used as the sole source of
supplemental protein in swine diets. In the diet of
newly weaned pigs, dried milk products such as
whey or skim milk are preferred due to the nature of
Sunflower Meal:
DE
Crude Protein
Lysine
Digestible Lysine
Digestible Threonine
Digestible Tryptophan
DebuUed
3115
40.5
1.39
1.03
0.97
0.35
97

116. much fibre as dchulled soybean meal, so that it
contains slightly less digestible energy than barley.
The standard meal contains less energy even than
wheat bran and much less than oats. Any discus-
sion of sunflower meal must differentiate between
the three types.
The amino acid profile of dehulled sunflower
meal is poor in comparison to soybean meal, largely
because lysine is much lower and threonine, another
important amino acid in barley and wheat based
diets, is somewhat lower. Of additional concern is
the fact that the availabiIity of lysine from sun-
flower meal is about 15% less than that from
soybean meal; threonine is also slightly less avail-
able. The replacement ofsoybean meal with
sunflower meal in barley-based diets will require
adjustment for both available lysine and threonine
content.
Fortunately it is the dehulled meal that is pro-
duced in Manitoba and it often becomes available at
a competitive price. It is produced by the pre-press,
solvent process. It can be used to completely
replace soybean meal in swine diets, especially
those for gestating sows and the late growing stage
(above 65 kg) where energy concentration is not so
critical. In early growing diets and lactation diets, a
drop in energy content will reduce productivity so
that care is required in replacing even part ofthe
soybean meal with sunflower meal. In medium to
high energy diets, such as starter and lactation
formulations, added fat and an increase in total
dietary protein or synthetic amino acids to adjust for
lower available lysine and threonine levels, is
advised.
Standard and partially-dehulled sunflower meal
must be used with even greater caution; because of
the very low energy concentration and high crude
fibre content, even partial ly-dehulled sunflower
meal should not be used to supply more than half of
the required supplemental protein in market hog
diets. Neither meal should be used in lactation or
starter diets because the energy content is too low.
Additional Reading and References
Baird, D.M. 1982. Kinds and levels of sunflower
meal with and without lysine supplementation
for finishing pigs. Proc. Georgia Nutr. Conf. pp.
74-79.
Dinusson, WE., 1990. Sunflower meal. Pages
465-472 In P.A. Thacker and R.H. Kirkwood, eds.
Nontraditional Feed Sources for Use in Swine
Production. Butterworths Publishers, Stoneham,
MA.
Jorgensen, H., W.C. Sauer and P.A. Thacker. 1984.
Amino acid availabilities in soybean meal, sun-
flower meal, fish meal and meat and bone meal fed
to growing pigs. J. of Anim. Sci. 58:926-934.
Sunflower Seeds
Interest in the sunflower as a crop has increased
tremendously in recent years. This interest is based
on the fact that the oil contained in the sunflower
seed supplies a very high level ofpolyunsaturated
fatty acids. Therefore, sunflower oil is highly
sought after as a vegetable oil for human consump-
tion. However, not all sunflower seeds are suitable
for the production of oil or for use as confectionery
seeds. As a consequence, whole sunflower seeds
are sometimes available for use as a livestock feed.
Sunflower seeds can be considered as high in energy
and medium in protein content. They contain on
average ofabout 40% oil. 20% crude protein and 29%
crude fibre. The high crude fibre level arises because
ofthe thick hull on the sunflower seed. Unfortunately,
there is little information concerning the levels of
other nutrients in the entire sunflower seed.
The results ofone experiment in which sunflower
seeds were fed to weanling pigs from four to eight
weeks ofage are presented in Table 4-34. In this
experiment, inclusion of 6.5 or 13% sunflower
seeds improved the average daily gain of the weaner
pigs while the addition of26% sunflower seeds
depressed performance. The reduction in growth
rate was associated with a reduced feed intake
suggesting that the high crude fibre content ofthe
sunflower seed limits its usefulness in starter diets.
In addition, supplementation with synthetic lysine
98

117. Table 4-34. Effect of Feeding Sunflower Seeds on the
Performance ofWeaner Pigs.
Adams et al., 1982, Univ. Ill. Agric. Exper. Station
Report. pp. 1-4.
did not appear to be beneficial. A maximum of
I 0% sunflower seeds is therefore recommended in
starter diets.
Sunflower Seeds(%)
0 6.5 13.0 26.0 26.0
Added Lysine +
In summary, the high crude fibre content ofthe
sunflower seed limits its usefulness in starter diets
and a maximum of I 0% sunflower seed is therefore
recommended. As the level of sunflower seed in
the diet of the growing pig increases, carcasses
become fatter, carcass firmness decreases and bacon
sliceability becomes more difficult. Therefore, it
would appear that market hogs should not be fed
diets containing more than l0% sunflower seed.
Finally, palatability problems have been observed at
levels ofgreater than 25% in diets fed to breeding
stock.
Additional Reading and References
Adams, K.L. and A.H. Jensen. 1985. Effect of
dietary protein and fat levels on the utilization of
the fat in sunflower seeds by the young pig. Anim.
Feed Sci. Technol. 13:159-170.
Sunflower seeds have been fed successfully to
sows during the last week of gestation and during
early lactation. The most dramatic effect observed
as a result of feeding sunflower seeds was a linear
increase in the percentage of milk fat. However,
piglet weaning weight and percentage survival were
unaffected by dietary treatment. Some palatability
problems were observed at inclusion levels greater
than 25% and therefore it would seem wise to limit
the level of sunflower seed to less than 25% of the
diet.0.55 0.56
1.03 1.04
1.87 1.86
0.61 0.63 0.63
l.15 l.l6 1.18
1.88 l.84 l.87
AD G (kg)
Daily Feed (kg)
Feed Conversion
From an experiment in which sunflower seeds
were fed to growing pigs (Table 4-35), it can be
seen that there was a linear increase in growth rate
as the level ofsunflower seeds in the diet increased.
However, as the level of sunflower seed in the diet
increased, carcasses become fatter, firmness de-
creased and bacon sliceability became much more
difficult. It appears that market hogs should not be
fed diets containing above 10% sunflower seeds
because ofdeleterious effects on carcass quality and
that results are improved by feeding unprocessed
seeds since heating reduces digestibility.
Table 4-35. Performance of Growing Pigs Fed
Graded Levels ofSunflower Seeds.
Sunflower Seeds (%)
0 2.5 5 10
Adams, K.L., C.C. Lin and A.H. Jensen. 1982.
Sunflower seeds in diets for young pigs. University
ofIllinois Agriculture Experimental Station Report.
pp. 1-4.
Average Daily Gain (kg)0.71 0.74 0.76 0.80
Average Daily Feed (kg) 2.36 2.46 2.53 2.60
Feed Conversion 3.32 3.34 3.28 3.30
Carcass Firmness' 3.70 3.30 3.00 2.50
Bacon Sliceability2
l. lO l.40 1.65 2.40
IodineNumber3 55.77 58.17 64.18 71.04
I Range of I to 5 with I the softest and 5 the firmest.
2
Range of I to 5 with I being the best and 5 the worst.
'Hartman et al., 1983, S. Dakota State 27th Ann. Swine
Day. pp.8-13.
Hartman, A.O., R.C. Wahlstrom and G.W. Libal.
1983. Sunflower seeds in growing-finishing swine
diets. South Dakota State 27th Annual Swine Day.
pp. 8-13.
Wahlstrom, R.C. 1985. Sunflowers in pig nutri-
tion. Pig News and information. 6: 151-154.
Wahlstrom, R.C., 1990. Sunflower seeds. Pages
473-480 In P.A. Thacker and R.N. Kirkwood, eds.
Nontraditional Feed Sources for Use in Swine
Production. Buuerworths Publishers, Stoneham,
MA.
99

118. Table 4-36. Trypsin Inhibition Levels in Spring
Triticale1
•
I
Acceptable level ofinhibition for hogs equals 60%
inhibition or less.
Adapted from Metzger, I 982. Unpublished Data.
Corvallis, Oregon.
Other factors which have been identified in
triticale include alkyl-resorcinols and tannins.
However, the levels of these factors are generally
low and therefore, their presence is usually of little
consequence in formulating diets for swine.
Soluble pentosans have also been identified in
triticale. It is postulated that pentosans form com-
plex bonds with the albumen fraction ofthe cereal
protein and thus decrease the digestibility of the
diet. It is also suggested that pentosans increase diet
bulkiness as a result oftheir water binding capacity
in the gastrointestinal tract and thus depress feed
intake.
64.05 ± 7.18
79.59 ± 8.71
72.00 ± 3.72
70.30 ± 0.86
65.60 ± 1.97
Trypsin InhibitionVariety%
Carman
Welsh
Triwell
*75L021
*79P439
New varieties oftriticale have recently been
developed which are much more resistant to ergot
infestation than were the older cultivars of triticale,
Examples of ergot resistant varieties are Welsh and
Carmen. When these varieties are fed and the ergot
concentration ofthe diet is kept below 0.1 %, it is
unlikely that any ergot-related problems will de-
velop for growing pigs fed triticale.
Several other anti-nutritional factors have been
isolated in triticale. Perhaps the most important is
the presence ofa high level oftypsin inhibitor
which has been shown to tie up the enzyme trypsin
and reduce the digestibility ofdietary protein.
There is a great deal ofvariation in the level of
trypsin inhibitor among varieties oftriticale (Table
4-36) and therefore producers should strive to
obtain cultivars with a low trypsin inhibitor levels.
Triticale
Triticalc iTritlcale hexaploide) is a relatively new,
synthetic, small grain crop produced by crossing
durum wheat with rye. The goal of plant breeders
in developing triticale was to combine the high
crude protein and digestible energy content ofwheat
with the high yields and protein quality ofrye. Its
name is derived by combining Triticum, the botani-
cal name for wheat, with Seca/e, the botanical name
for rye.
One of the most attractive features oftriticale is
its relatively high digestible energy content. For
pigs, the digestible energy content has been esti-
mated to be approximately equal to wheat and com.
A relatively low crude fibre content (2.4%) is one
ofthe factors accounting for this high energy level.
Triticale has not been a major crop in Canada and
therefore, large quantities oftriticale have not been
fed to livestock. However, from time to time,
significant quantities oftriticale become available
and can be successfully utilized as an energy source
in swine diets.
Like rye, triticale tends to be susceptible to ergot
infestation (see chapter 11 ). Also, as is the case
with rye, it is important to remember that ergot is a
fungus contaminating the grain and not a factor
inherent to the grain itself.
The crude protein content oftriticale has been
reported to vary considerably, depending on the
cultivar and growing conditions, with protein
contents ranging from 11.8 - 22.5% being reported.
The average is about 16%. Triticale has a better
balance of amino acids for pigs than most other
cereals, although this may be quite variable depend-
ing upon variety. Most amino acids tend to be
present at a level intermediate to that of durum
wheat and rye. As is typical ofmost cereal grain
proteins, triticale is low in cystine, methionine,
threonine and lysine. Lysine is the first limiting
amino acid in triticale while threonine is reported to
be the second limiting amino acid. The
availabilities ofamino acids in triticale exceed those
of barley by approximately 5 - I 0%.
100

119. In evaluating triticale as an energy source for
swine, it is important to differentiate between
problems associated with ergot and problems
associated with the grain itself. As stated earlier,
triticale with an ergot level above 0.1% should not
be fed to growing swine. Ergot-infested triticale
should not be fed to the breeding herd. Therefore,
the remaining discussion shall relate to ergot-free
triticale.
There is very little information concerning the
feeding value of triticalc in diets fed to breeding
stock. Until more research is conducted to deter-
mine the nutritive value oftriticale for breeding
stock, a limit of25% of the total diet is suggested.
Additional Reading and References
Adeola, 0., Young, L.G. and McMillan, r., 1987.
OAC Wintri tritieale in diets ofgrowing swine.
Can. J. Anim. Sci. 67: 187-199.
Triticale Wheat Com
Jilek and Barnett, 1981, Univ. Florida 26th Ann. Swine
Field Day Res. Report. pp. 32-34.
Table 4-37. Performance of Grower Pigs Fed Diets
Containing TriticaJe, Wheat or Corn (18-98 kg).
Some scientists have reported that triticale is rela-
tively unpalatable for starter pigs. Others observed no
problems. Since starter pigs are often reluctant to eat
solid feed feedstuffs ofquestionable palatability
triticale should be used with caution. Should it be
used, then it is recommended that initially it not be
included at more than 25% ofthe total diet.
Wheat
Wheat tTriticum aestiuum) is grown primarily for
the human food market and is used in livestock
diets only when market conditions or quality dis-
counts make it economical to do so. However, feed
grade wheat, destined specifically for the animal
feed market, is also grown in various parts of
Canada. From an animal feed perspective, there is
no difference between red or white wheat varieties,
nor between those seeded in the spring or fall.
There are slight differences between hard and soft
wheat; the former tend to have more protein, a
higher content ofessential amino acids, although a
Radecki, S.V and Miller, E.R., 1990. Triticale.
Pages 493-499 In P.A. Thacker and R.N. Kirkwood
eds. Nontraditional Feed Sources for Use in Swine
Production. Butterworths Publishers, Stoneham,
MA.
Lun, A.K., Smulders, J.A.H., Adeola, 0. and L.G.
Young, 1988. Digestibility and acceptability of
OAC Wintri triticale by growing pigs. Can. J.
Anim. Sci. 68: 503- 510.
Miller, E.R. and J.P. Erickson. 1980. Triticale as
an ingredient for pig diets. Pig News and Informa-
tion. 1 :207-210.
Jilek, A.F. and R.D. Barnett. 1981. Triticale and
wheat as energy sources in swine grower and
finisher rations. University ofFlorida 26th Annual
Swine Field Day Research Report. pp. 32-34.
King, R.H., 1980. The nutritive value of triticale
for growing pigs. Proc. Aust. Soc. Anim. Prod.
13:381-384.
0.84
2.57
3.06
0.90
2.80
3.11
Average Daily Gain (kg) 0.90
Average Feed Intake (kg) 2.78
Feed Conversion 3.09
Triticale can be successfully utilized as an energy
source for growing swine. Most of the early work
with triticale indicated that it was relatively unpalat-
able and as a consequence, most nutritionists have
Iimited it to about 50% of the cereal portion ofthe
diet. However, more recent work with ergot-free
triticale indicates that triticale is comparable in
feeding value to both wheat and corn (Table 4-37).
Therefore. it may be possible to include triticale at
higher levels than was previously recommended.
Producers who wish to feed it are advised to start
with about 25% triticale in the diet and gradually
increase the level. The performance ofthe pigs
should be monitored closely to ensure that no
problems arise. Some producers who have fed
triticale have reported problems with excessive
dust. This problem can be addressed by using a
coarser screen size when grinding or by incorporat-
ing 2 - 5% fat into the ration. Pelleting the ration
would also be beneficial.
101

120. slightly inferior profile, and less energy. However,
both soft and hard wheat support equal perform-
ance in growing pigs (Table 4-38) and in starter
diets (Table 4-39). Studies of new varieties of feed
wheat, such as the Prairie Spring Wheat variety
Biggar or dwarfwheat have not revealed any
serious problems, suggesting they can be used in
swine diets according to nutrient composition
without concern. Differences in feeding value
between different samples ofwheat are more
attributed to variation in growing and harvesting
conditions that to differences between the various
varieties ofwheat. In general, when amino acids
are properly balanced with energy, wheat makes an
excellent feed ingredient for swine feed. Dustiness
may be a problem, especially for producers more
familiar with barley diets. Coarser grinding or the
addition of 0.5 to 2.0% fat to the diet will prove
helpful.
Wheat contains approximately I 0% more digest-
ible energy (DE) than barley and only slightly less
energy than corn. However, and as discussed in
Chapter 3, there can be considerable variation in the
DE content of various wheat samples. This is
especially the case when wheat is harvested prema-
turely and/or under poor conditions. For example, a
recent study at the Prairie Swine Centre indicates
that differences in DE content between wheat
samples can be as high as 300 Kcal/kg or I 0% of
the mean DE content. This would result in differ-
ences of feed efficiency of I 0%. A means to
predict the DE content of individual wheat samples
is based on chemical analyses (in particular dry
matter, fibre and protein) and using mathematical
equations such as the following:
DE (Kcal/kg of dry matter) = 3584 + 38.3 x Protein
content(% in dry matter) - 16.0 NDF content(% in
dry matter).
Item
Avg Gain per Day (kg)
Avg Feed per Day (kg)
Feed Conversion
Hard
0.81
2.96
3.67
Wheat
Soft
0.84
3.10
3.69
Bushel weight is a poor predictor ofthe feeding
value of individual wheat samples. The results of
studies conducted at Prairie Swine Centre indicate
that there were basically no differences in DE
content between samples that had bushel weights of
53 and 62 lbs. Only when the bushel weight was
below approximately 53 lb, was a significant
reduction in DE content noted. Actual animal
performance studies suggest that the feeding value
ofwheat with bushel weights less than 56 should
not be discounted at all, and wheat with bushel
weights lower than that can be fed to pigs over 65
kg with appropriate adjustments offormulas.
Adapted from Hinens, 1982, Kansas St. Univ. Swine Day.
pp. 104-107.
Table 4-38. Comparison of Hard and Soft Wheat in
the Diet of Pigs from 61-121 kg.
Table 4-39. Replacement of Hard Red Spring Wheat
with Soft Wheat in Pig Starter Diets.
Percent soft wheat
0 20 40 60
Initial wt, kg 7. I 7.4 7.2 7.2
Ave. daily gain, kg 0.46 0.47 0.51 0.48
Ave. daily feed kg 0.67 0.68 0.71 0.68
Feed conversion 1.45 1.45 1.39 1.41
Adapted from Magowan and Aherne, 1987, Proc.
Western Nutr. Conf. pp 125-127.
The amino acid content ofwheat is substantially
higher than that in com and similar to that in barley.
In comparison to com, wheat contains approxi-
mately 50% more lysine and triple the amount of
tryptophan. This reduces the need for supplemental
protein in wheat-based diets as compared to com-
based diets. In some samples of wheat the protein
content can be as high as 16%, especially when
growing conditions are dry. It should however, be
stressed that the quality ofprotein (amino acid
balance) in wheat is poor. For example, the lysine
content expressed as a percentage ofcrude protein
(N X 6.25) present in wheat is approximately 2.9%
which is less than half ofthat in soybean meal. Tn
102

121. addition there are important differences in the
protein quality between wheat, barley and corn. In
spite of the differences in protein content between
wheal and barley there are basically no differences
in the lysine content. Failure to recognize these
differences in protein quality, by formulating diets
based on crude protein (N x 6.25) rather than amino
acid levels, will result in sub-optimal pig perform-
ance. A final point is that the amino acid to energy
ratio should be considered as well. In particular,
when wheat replaces barley in pig diets.
The actual amino acid content in individual wheat
samples is largely affected by the protein content in
individual wheat samples and can be predicted
based on the mathematical equations presented in
chapter 3. These equations indicate that an increase
in protein does not result in a proportional increase
in many ofthe essential amino acids such as lysine.
The changing protein content reflects largely the
change in the amount of gluten present; gluten is
rich in non-essential amino acids and is a poor
source of essential amino acids such as lysine.
The contents ofminerals and vitamins in wheat
are not sufficiently different from those in com and
barley to warrant major changes in diet formulation.
The feeding value ofwheat as compared to that in
corn and barley. is directly the result of differences
in digestible energy and amino acid contents be-
tween these cereal grains. The results of many
studies indicate that performance ofpigs fed wheat
based diets is similar to that ofpigs fed corn based
diets, provided that the proper dietary amino acid to
energy ratios are maintained. When comparing
wheat to barley-based diets, feed efficiency is
generally close to 10% better in the wheat-based
diets. Differences in growth rates between pigs fed
barley and wheat based diets will depend on the
body weight ofpigs. In starter pigs it is generally
I 0% higher on wheat based diets and the difference
tends to become smaller as pigs grow heavier. As
finishing pigs are able to compensate for changes in
dietary energy density, by adjusting voluntary feed
intake, difference in growth rate in finishing pigs
fed either barley or wheat based diets are small and
can often not be detected.
The choice ofcereal grain in properly formulated
pig diets should purely be driven by economical
considerations. In diets for starter, grower and
finisher pigs wheat can be used as the sole cereal
grain. Tn many practical nursing sow rations, the
inclusion levels ofwheat can be as high as 50%.
There is no need for high energy ingredients such as
wheat in dry sow rations. However, provided that
attention is paid to feed processing and feeding
management, the inclusion level ofwheal can also
be 50% in the dry sow diet.
When wheat is used as a pig feed ingredient close
attention should be paid to feed processing and in
particular to the fineness ofgrinding.
Wheat should not be ground too finely since it
becomes very floury and palatability may suffer.
Finely ground wheat does not flow as well in self-
feeders and the incidence ofstomach ulcers may
also increase with a fine grind. For growing swine,
most studies have demonstrated that rolled wheat
will perform as well as coarsely ground wheat in the
diets ofmarket hogs. Results ofone representative
study revealed that rolling was better than grinding,
and that pelleting was the best ofall treatments.
This particular study revealed that both hard and
soft wheat responded in the same manner to
processing treatment. It may be difficult to obtain
and maintain a uniform feed mixture with rolled
wheat, so a medium grind (approximately 4.5 mm
to 6.4 mm screen) is recommended. Ifstomach
ulcers become a problem the addition of 5-10%
whole oats in pelleted rations, or coarsely ground
oats in mash rations generally solves the problem.
Off grade wheat often becomes available lo the
animal feed market and questions arise about its
suitability for swine. Studies conducted at the
Prairie Swine Centre indicate that the DE content,
offrost damaged wheat is similar to that in normal
wheat. This would suggest that the actual feeding
value of frost damaged wheat is similar to that of
regular wheat as well. The results ofa France study
(Table 4-40) indicate that the feeding value of wheat
that was partially sprouted was the same, or even
slightly better, than that of regular soft wheal.
103

122. Table 4-40. Performance of Starter Pigs Fed Either
Sprouted or Regular Soft Wheat.
they may also be called wheatings, thirds or coarse
middlings.
Daily intake (kg)
Daily gain (kg)
Feed Conversion
.87
.45
1.94
.90
0.50
1.81
.87
.51
1.71
The greatest problem associated with the use of
these milling by-products in animal feed is the lack
of uniformity due to mixing of fractions. Some
bran is always included in wheat shorts, but increas-
ing the extent will decrease energy content and alter
the amino acid profile. Bulk density has been
proposed as a gauge of nutritional value, since it
would change as the proportion ofvarious fractions
changes.
Additional Reading and References
Gatel, F. And 0. Bourdon. 1989. Effects of pre-
harvest sprouting on the feeding value ofwheat for
pigs. Pig News and Information. 10 (vol 2): 159-
160.
de Lange, C.F.M., 0. Gillis, L. Whittington and J.
Patience. 1993. Feeding value of various wheat
samples for pigs. 1993 Annual Research report.
Prairie Swine Centre Inc., pp 27-30.
Magowan, WI. 1991. Wheat: soft and dwarf. In
(Thacker. P.A. and R.N. Kirkwood, Ed.): Non-
traditional feed sources for use in swine production.
Butterworths Publishers, 80 Montvale Avenue,
Stoneham, MA 02180. U.S.A., pp 501-508.
I
Soft wheat (I idcl)
2 Soft wheat (Fidel), based on visual inspection - 15%
sprouted
1 Hard wheat (Cando). based on visual inspection - 20%
sprouted
Adapted from Gate! and Bourdon, 1989. Pig news and
Information 10 (vol 2): 159-160.
Scabby wheal, having been infected with the
mold Fusarium graminearium, has been shown in
feeding trials to reduce growth rate in swine. In
starter pigs, l ppm ofvomitoxin in Fusarium-
contaminated hard wheat was sufficient to impair
growth rate in the first week on the trial. There was
some compensation as the time on test progressed,
but even after three weeks, vomitoxin at 2.4 ppm
reduced rate and efficiency ofgain. Removal ofthe
contaminated grain from the diet did not result in
compensatory gain, indicating that losses due to
moldy wheat will permanently increase the number
of days to market.
Control' Sproutcd2 Sprouted'
Wheat is processed into flour for human con-
sumption and generates by-products which can be
successfully used in swine diets. The wheat kernel
consists of 85% endosperm, 13% bran and 2%
germ. The objective of flour milling is to separate
the endosperm from the bran and germ in as effi-
cient a manner as possible. On average, by-prod-
ucts represent only about 28% of the total grain
milled, indicating that the process is quite efficient.
Typically, lhc by-products include wheat shorts,
wheat middlings. red dog and wheat bran, with bran
accounting for about 50% of the total. Although
Canada exports much of its wheat and mills a
relatively small portion domestically, flour milling
by-products arc still available to the livestock
industry. The naming ofthese materials is confus-
ing because of little consistency world wide. For
example, Canadian wheat shorts arc roughly equiva-
lent to American middlings. In some countries,
Wheat Bran
Wheat bran consists mainly ofthe outer husk of
the wheat kernel. Because of its high fibre content,
bran is low in digestible energy and is inferior even
to oats in this regard (Table 4-41 ). Because of its
relatively low energy content, wheat bran is not an
ingredient ofchoice in swine diets.
Wheat Bran
DE 2475
Crude Protein 15.5
Lysine 0.59
Digestible Lysine 0.32
Digestible Threonine 0.25
Digestible Tryptophan 0.16
Calcium 0.12
Phosphorus 1.16
104

123. Where constipation is a concern, especially in
sows around the time of farrowing, bran at 5-15%
of the total diet can be most helpful. Nutritionists
must ensure that when adding fibre to the diet and
thus reducing constipation, the sow's need for
energy is not compromised. Lactation may be a
time when constipation is most likely, but it is also
the time when energy demands are very high.
Consequently, bran should be matched with oil or
some other concentrated energy source in the diet to
ensure that the sow's energy intake is satisfactory.
Wheat Shorts
Wheat shorts consist offine bran and parts ofthe
endosperm from the original wheat kernel. Because
ofthe endosperm fraction, wheat shorts contain less
crude fibre and more energy than bran. In terms of
energy content, wheat shorts are approximately
equivalent to barley and contain somewhat higher
levels ofcrude protein, lysine and threonine. (See
Table 4-41.)
Wheat Shorts
DE 3140
Crude 17.5
Lysine 0.70
Digestible Lysine 0.50
Digestible Threonine 0.32
Digestible Tryptophan 0.18
Calcium 0.10
Phosphorus 0.85
Wheat shorts are potentially a very good ingredi-
ent for swine diets; pellet mill operators like them
because they tend to improve pellet durability.
Potential concerns in using wheat shorts in pig feeds
include the variability ofthe product and the high
fibre level. Recommended maximum inclusion
levels ofwheat short are l0% for starter pigs and
approximately 40% for grower-finisher pigs and
sows. However, when diets are properly balanced
for energy and amino acid contents and when a
good consistent quality ofwheat shorts is used,
animal performance can be maintained at inclusion
levels higher than the recommended maximums. If
the diet is not pelleted, dustiness could become a
problem, so that either the proportion of shorts
should be reduced or fat added to the diet to settle
the dust.
Table 4-41. Typical Specifications for Wheat and its
By-products
Ingredient Crude Protein Fat Fibre
Minimum(%) Maximum(%)
Wheat2
13.6 1.7 2.7
Bran' 14.0 3.5 12.5
Shorts' 15.0 4.0 8.0
Middlings' 15.5 2.5 4.5
Germ' 25.0 9.0 2.5
I
Millfeed Manual, Millers' National Federation.
2
Appendix I.
Wild Oat Groats
Despite intensive efforts at chemical and cultural
control, wild oats (Avenafatua) continue to con-
taminate a large proportion ofthe grain produced in
Western Canada. Approximately 40% of the
dockage assessed on locally produced cereal grains
and as much as 1% ofthe total harvest ofgrain is
comprised ofwild oats. Due to their black-col-
oured hull, wild oats must be removed before the
grain can be exported or processed for human
consumption. Over 200,000 tonnes ofwild oat
seeds are separated annually at commercial seed
cleaning plants across Canada.
Wild oats have traditionally been marketed as
Mixed Feed Oats and have been utilized almost
exclusively in diets fed to ruminants. The presence
ofa highly fibrous hull limits their usefulness in
diets formulated for monogastrics. However, a
technique for dehulling wild oats has been devel-
oped recently and the dehulled kernels, commonly
called groats, may have considerable potential to
replace domestic oat groats in diets fed to poultry
and swine.
Wild oat groats contain significantly higher levels
ofcrude protein in comparison with domestic oat
groats ( 19.9 versus 15.5%). Despite large differ-
ences in protein content between the wild and
105

124. Table 4-42. Performance of Starter Pigs (7 - 25 kg) Fed Various Oat Products1.
Wheat Oat Feed Wild Oat Wild Oat
Groat Oats Groat Flake
Average Daily Gain (kg) 0.39 0.39 0.38 0.37 0.35
Average Daily Feed (kg) 0.64 0.65 0.65 0.61 0.60
Feed Conversion 1.64 1.62 1.70 1.64 1.70
Thacker and Sosulski, 1994. Anim. Feed Sci. Technol. 46: 229-237.
I
Diets based on 25% oat product added at the expense of wheat.
domestic oat groats, there would appear to be little
difference in amino acid composition between
common and wild oat protein. With the exception
of lysine and threonine, all ofthe essential amino
acids are present in sufficient quantity to meet the
requirements of the starter pig (IO - 20 kg).
Wild oats contain a higher level ofether extract
than domestic oat groats (7.8 versus 6.3%). Chemi-
cal analysis has shown that almost 90% ofthe lipid
in wild oats is in the form oftriglycerides. These
triglycerides are highly unsaturated with the oleic,
linoleic and linolenic acid levels being 46, 35 and
2%, respectively, of the total fatty acids. The
polyunsaturated fatty acids are desirable nutrition-
ally, but they are also subject to oxidative instability
during storage especially after seed grinding.
There is an active lipase in the pericarp of the
wild oat. The lipase is not in contact with the lipids
in the intact kernel but crushing or milling the seed
will result in hydrolysis ofthe triglycerides into free
fatty acids, even at relatively low seed moisture
levels. The free fatty acids are much more suscepti-
ble to oxidation into rancid, bitter breakdown
products than the intact triglyceride. Therefore, it is
essential to steam the groats thoroughly to destroy
the lipases in the bran before proceeding to process
the groat into feed products. Once the enzyme has
been inactivated, the dry milled products can be
stored for several months without a significant
breakdown of lipids, especially if cool temperatures
are maintained.
The performance ofstarter pigs fed diets contain-
ing wild and domestic oat groats and flakes is
presented in Table 4-42. In this experiment, the
control diet was based on wheat and soybean meal
while the remaining diets contained 25% domestic
oat groats, wild oat groats, toasted oat flakes or
toasted wild oat flakes added at the expense of
wheat. All diets were formulated to contain ap-
proximately 20% crude protein and synthetic lysine
was added so that all diets supplied approximately
0.9% lysine.
The growth rate ofpigs fed diets containing either
wild oat groats or wild oat flakes was similar to that
obtained with domestic oat groats and flakes.
Toasting and rolling ofoat groats or wild oat groats
did not appear to improve their nutritional value.
The results ofthis experiment indicate that one may
include up to 25% wild oat groats in starter diets
without any adverse effects on performance. Based
on the high cost ofwild oat groats, there would
appear to be little potential for including them in
grower diets or in diets fed to breeding stock.
Additional Reading and References
Sosulski, F.W. and K. Sosulski. 1985. Processing
and composition of wild oat groats (Avenafatua
L.). J. Food Eng. 4:189-203.
Sosulski, F.W.. K. Sosulski and J.P. Olson. 1985.
Nutritive value of wild oat groats and flakes. Can.
Inst. Food Sci. Technol. 18:220-225.
Thacker, P.A. and F.W. Sosulski. I 994. Use of
wild oat groats in starter rations for swine. Anim.
Feed Sci. Technol. 46: 229-237.
Thacker, P.A., 1990. Wild oat groats. Pages 509-
515 In P.A. Thacker and R.N. Kirkwood, eds.
Nontraditional Feed Sources for Use in Swine
Production. Butterworths Pub., Stoneham, MA.
106

125. Fats and Oils
Fats and oi Is are a very concentrated source of
energy, often containing 2.5-3.0 times the energy of
cereal grains. They also tend to be more expensive
per calorie than cereal grains and thus are used only
where higher energy levels are required., such as
those for weanling pigs, lactating sows of fast
growing market hogs. They are also used to supply
essential fatty acids, to suppress dust, facilitate
pelleting and reduce wear in feed manufacturing
equipment. Jn fact, as the swine industry has
developed, and expectations for increasingly higher
standards ofperformance rise, fat usage in pig diets
has increased.
Whenever fat is added to swine diets, careful
adjustment ofother nutrients, especially amino
acids, is required to ensure the diet remains bal-
anced with respect to nutrient to energy ratio's and
in particular amino acid to energy ratio's. If,
through the addition offat to the diet, the energy
content is raised without proper adjustments ofthe
dietary amino acid levels, then animal performance
will be sub-optimal. In market hogs carcass index,
growth rates and feed efficiency will be reduced and
nursing sows will not increase their milk produc-
tion. As fat is added to the diet. daily feed intake is
generally slightly reduced, but the pig will consume
more energy per day, up to a maximum that will be
determined by the diet and by such factors as
genetics and environmental temperature.
Like many branches of nutrition, fats have a
specific set ofterminology that helps to describe
their nutritive value. Most fats are present in a
compound called a triglyceride (see Figure 4-2). Tt
is made up of three fat chains called fatty acids, that
are linked together at one end like tines on a fork.
Ifthe fatty acids are not linked together but exist as
single units, they are called free fatty acids. Some
fats contain only two fatty acids linked together
with the third position occupied by another com-
pound such as a phosphorus compound.
The chemical and nutritional characteristics ofall
fats are dictated by the individual fatty acids. Some
are 'loose structures and thus are soft at room
temperature. Vegetable oils are liquid at room
temperature because they contain many ofthese
'loose' or unsaturated fatty acids. Other fatty acids
are very firm and are hard at room temperature.
They are called saturated fatty acids. Tallow
contains a high proportion ofsaturated fatty acids;
for this reason, tallow must be heated to liquefy it
so that it can be mixed properly into the diet. Oil is
generally the term used to describe fats that exist as
a liquid at room temperature. Tallow and lard arc
solid at room temperature and thus are not oils.
Fatty acids are described not only as saturated or
unsaturated, but also short- or long-chained. This
refers to the physical length of the fatty acid mol-
ecule. The significance ofthese terms, from a
nutritional perspective, is explained below.
In some respects, fatty acids are to fat what amino
acids are to protein. However, there are some major
differences. Only two fatty acids are essential in the
diet (linoleic, a member ofthe w-6 family of
polyunsaturated fatty acids and linolenic, a member
ofthe w-e family ofpolyunsaturated fatty acids),
whereas there are ten essential amino acids. Also,
proteins contain only amino acids while fats contain
fatty acids plus other compounds, like glycerol,
sugar and phosphorus.
The requirements for essential amino acids in pigs
are not well established. For example, there is still
considerable debate on the efficiency with which
...
triglyceride
Figure 4-2. Triglyceride.
glycerol + 3 free fatty acids
107

126. pigs can convert linolenic acid pigs to other polyun-
saturated fatty acids that belong to the family ofw-
3 fatty acids, and that are essential for normal
animal metabolism. Some studies suggest that the
ratio of w-6 to w-3 fatty acids in the diet is as
important for the conversion ofthese w-3 fatty
acids (see "essential fatty acids" in chapter 3).
The term fat is very general, referring to a group
of ingredients including animal fats, vegetable oils
and related compounds. Feed fats can be divided
into six general categories: animal fat, poultry fat,
blended feed grade animal fats, blended animal and
vegetable fats, feed grade vegetable fats and
soapstocks. Animal fat refers to rendered fats from
beef or pork by-products. It includes packing house
offal and supermarket trinunings. Because beef fat
(tallow) tends to be constant regardless ofthe diets
fed to cattle, it tends to be more consistent in terms
offatty acid profile that pork fat (lard) which
depends on the diets fed to pigs.
Poultry grease is the rendered fat from poultry
offal. Blended animal fats may include mixtures of
pork lard, beef tallow, poultry grease and possibly
restaurant grease. Blended animal and vegetable
fats may include proportions of the above men-
tioned animal fats plus fats ofplant origin. Vegeta-
ble oils are derived from the refining ofvegetable
fats such as soybean oil, canola oil or corn oil.
Soapstocks, also called foots, contain products not
wanted in oils destined for the human food trade
including free fatty acids.
Good quality tallow or poultry grease may con-
tain no more than 15% free fatty acids, while
soapstocks contain approximately 50% free fatty
acids. They can be used in the manufacture ofsoap
or as a fat supplement in animal diets. Soapstocks
are separated from the higher grade ofoils by the
addition ofan alkali which causes them to settle out,
allowing the still liquid oils to be removed. The
precipitate is then re-suspended by adding an acid;
for this reason, they are sometimes called acidulated
fatty acids. In concentrated form, they are quite
corrosive, and must be used with care in the feed
manufacturing process. Once they are diluted in the
feed, they have proven to have excellent feeding
value. ln terms offatty acid composition, they are
quite similar to the parent vegetable oil.
High grade vegetable fats are not commonly used
in swine diets due to cost. On the prairies, crude
canola oil is sometimes used by individual farmers
who mix their own feed because it is easy to handle
in a simple mill. Tallow and lard as well as by-
product fats are commonly used in swine diets,
although vegetable fats may be preferred due to
higher energy and essential fatty acid content.
A variety of chemical tests can be carried out on
fats to determine their nutritional quality. Melting
point refers to the temperature at which the material
changes from a solid to a liquid. Vegetable fats
with a high proportion of 'loose' or unsaturated
fatty acids have a low melting point, meaning they
are liquid at room temperature. Fats ofanimal
origin such as lard and tallow, have a lower propor-
tion ofunsaturated fatty acids, and thus a higher
melting point. Consequently, they are solid at room
temperature and must be heated before being added
to the feed mix.
Undesirable impurities in fats can be measured.
These include moisture (water, should be less than
l%), insolubles (skin, hair, bone; should be less
than .5%) and unsaponifiable matter (should be less
than l%). As undesirable impurities rises, energy
content is reduced. Free fatty acid content is not a
good criteria ofquality. Once triglycerides enter the
gut, they are converted to free fatty acids. How-
ever, it the fat source normally has a low free fatty
acid concentration and it suddenly rises, it is a sign
that deterioration has occurred.
One inexpensive test conducted by some commer-
cial laboratories is the iodine value analysis. It
determines the proportion of unsaturated and
saturated fatty acids and thus helps to determine
uniformity of fat supply. A change in iodine
number would reflect a change in the composition
of the fat and thus indicate a need to discuss product
source with the supplier. Table 4-43 illustrates how
changing fatty acids in the fat can alter iodine value.
A hypothetical fat containing 50% oleic acid and
50% linolenic acid would have an iodine value of
1.8 while another fat, with equal portions of
palrnitoleic, oleic and linoleic acids would have an
iodine number of 1.22.
108

127. Fatty Acid
C 14: I Myristoleic
C16: I Palmitoleic
Cl8:I Oleic
Cl8:2 Linoleic
Cl 8:3 Linolenic
Multiply by:
1.10
1.00
0.90
1.80
2.70
fat ingredients so errors must be avoided. A
number of factors can influence the digestibility of
feed fats and thus their contribution to the energy
content ofthe diet. Long chain saturated fatty acids
are not well accepted by the intestinal tract and are
poorly digested unless mixed with unsaturated fatty
acids which make them more compatible with the
digestive processes. Thus the ratio of
unsaturated:saturated fatty acids will help to indi-
cate the digestibility of a fat source.
Table 4-43. Estimating Iodine Value from Fatty Acid
Composition of a Fat.
Other factors that are considered include colour
and odour, A relatively recent concern surrounding
feed grade fats is safety, or more specifically,
freedom from compounds that make the product a
health hazard. Well-publicized examples of such
compounds as PCB's (polychlorinated biphenyl:
poisonous environmental pollutants which tend to
accumulate in animal tissues) contaminating feed
grade fats has focused new attention on this subject.
Quality-conscious feed companies know that there
is no such thing as a cheap source offat and avoid
special "deals" that might come along. Iffarmers
are buying fat ingredients, they would be well
advised to follow the same thinking.
All fat supplements, irrespective of quality or
source, must contain an antioxidant to prevent
rancidity. Common antioxidants include propyl
gallate, BHT (butylate hydroxytoluene), GHA
(butylate hydroxyanisole) and ethoxyquin. Failure
to use properly stabilized fats will reduce palatabil-
ity and could compromise the pig's status with
respect to vitamin E and selenium Since rancid fat
in the diet leads to damage ofcell membranes. this
situation must be avoided. If a poor grade offat is
suspected, additional vitamin E and selenium
should be added to the diet. The rancidity of fats
can be evaluated by determining the peroxide value.
This value should not exceed 5.0 milli-equivalent
per kg. Raw oil in seeds, such as canola or
soybeans, contain natural antioxidants such as
vitamin E. However, these may deteriorate during
fat extraction procedures and artificial antioxidants
are required.
It is important to use a correct energy value for
fats used in swine diets. In some cases, I 0-15% of
the total energy in the diet may be supplied by such
The iodine number, which estimates the ratio of
unsaturated:saturated fatty acids, is therefore very
useful to the nutritionist. Fat digestibility appears to
be maximized when the unsaturated:saturated ratio
is 2.0 or above. Digestibility falls rapidly below
2.0 and at 1.0, digestibility is reduced by about
20%. Short-chain fatty acids, whether or not they
are unsaturated are well accepted by the gut and are
therefore well absorbed. Fibre in the diet reduces
the digestion offat due to an increase in rate of
passage. It has been estimated that for every l %
crude fibre in the diet, fat digestion is reduced by
1.3 to 1.5%. In Table 4-44 the digestible energy
contents ofselected fats and oils are summarized. It
should be noted that in net energy systems the
available energy content offats and oils, relative to
that in other ingredients is much higher than in
digestible energy systems (chapter 3). This is
because dietary fat can be incorporated directly in
body fat (even in very lean pigs a substantial
amount of essential body fat needs to be deposited)
or in milk fat and at low heat increments of feeding.
The relative feeding value offats is thus more
accurately represented in net energy than in digest-
ible energy systems.
It is difficult to suggest minimum and maximum
inclusion levels of fat in pig feeds. With the excep-
tion ofnewly weaned piglets, pigs are able to utilize
added fat at inclusion levels that exceed I 0%.
However, at inclusion levels that are higher than 6-
8% it becomes difficult to process and handle feed
(bridging in bins and feeders). Given the (high)
cost per unit ofenergy. the economics of using fat
should be considered as well.
109

128. Table 4-44. Digestible Energy Content of Selected Fat Sources.
Energy
Fat
Vegetable Origin
Canola Oil
Soybean Oil
Soapstocks1
Animal Origin
Grease (Poultry)
Lark (Pork)
Tallow (Beet)
6
16
29
43
51
94
84
71
57
49
Digestible Metabolizable
Kcal/kg
8800 7300
8800 7275
7850 7150
8625 8200
7850 7550
8200 7900
Saturated Fat% Unsaturated Fat%
Apendix, Table I .
I
Depends on the origin of the soapstock.
The results of studies where the effect ofadded
fat in diets for starter pigs has been evaluated have
been inconsistent. In many studies no or little
change in growth rate or feed efficiency has been
observed during the first two weeks fo!Jowing
weaning. This may be attributed to the reduced
digestibility and the piglets inability to metabolise
some types offats, in particular highly saturated,
long chain fatty acids. Fat utilization will be im-
proved when medium chain fatty acids (such as
these in coconut oil) or when unsaturated fats (oils
are used).
Fat can be included at high levels in diets for pigs
that are older than 6 weeks. In diets for starter and
grower pigs the inclusion offat will increase both
the energy content ofthe diet and the daily energy
intake. The value ofadded fat is thus determined
by improvements in both feed efficiency (basically
proportional to increases in dietary energy density if
diets are properly balanced for nutrient to energy
ratios) and in growth rate (basically proportional to
dietary energy density as well). As finishing pigs
are better able to adjust for changes in dietary
energy density (by adjusting daily feed intake), the
value ofadded fat in finishing diet should be based
on improvements in feed efficiency only.
A potential concern with the inclusion of large
quantities offat in the finishing diet is the direct
relationship between the quality ofdietary fat and
carcass fat. As more unsaturated fat is included in
the diet for finishing pigs, carcass fat will become
softer, more prone to oxidation (to become rancid).
This will affect colour. shelflife and consumer
acceptance offresh pork products. Some recom-
mendations are to maintain the total oil content
below 5% in finishing diets. In practical terms this
means that in a com-based diet the inclusion level
offull fat soybeans should not exceed 10% (or less
than 2% added oil), and that in a barley based diet
the inclusion level offull fat canola seed should not
exceed 7.5% (or less than 3% added oil).
The inclusion of fat in nursing sow diets has been
proven to be beneficial in many studies. In a recent
comprehensive review ofthe available literature
conducted by researchers at the University of
Minnesota, fat in the saw's diet increased litter
weaning weights in 18 out of24 studies, and
lactation weight loss in the sow was reduced in 11
out of 15 studies (Table 4-45). In some studies the
response to fat in the sows diet was small.
110

129. Table 4-45. Summary of Responses to Supplemental Fat in Sow Diets.
Responses Total No. of
ltem Positive Negative Response Comparisons
Piglet survival (%)* 14 6 2.7% 369
Lactation feed intake
(kg/d) 3 16 -.2 kg/d 833
ME intake (Mcal/d) 19 0 I .24Mcal/d 834
Litter weaning weight (kg) 18 6 1.65 kg 1150
Lactation weight change in sows (kg) l l 4 1.5 kg 697
* When treatment mean survival is less that 80% and when more than I 000 g of fat was fed to the sow prior to
farrowing; derived from Pettigrew and Moser, 1991.
The addition of fat to the late gestation diet may
not increase birth weight but will reduce the energy
stores in the piglet at birth. The addition offat had
a positive effect on piglet survivability in 14 out of
20 experiments (Table 4-45). This was especially
the case when birth weights were low and pre-
weaning mortalities were high (more than 20%).
The effects are more due to fat per see rather than to
the increase in the daily energy intake prior to
farrowing. An additional benefit of fat in the
gestation diet is that the fat content ofcolostrum is
increased. In order to get these benefits, sows
should consume approximately 1 kg offat in the
week prior to farrowing. In a direct comparison,
medium-chain fatty acids in the gestation diet
appeared more effective than long-chain fatty acids
from soybean oil in reducing pre-weaning mortality.
As in growing-finishing pigs, it is extremely
important to maintain a proper balance between
amino acid and energy intake in nursing sows. A
deficiency in protein during lactation maybe more
detrimental to sow reproductive performance than a
deficiency in energy.
Due to a more efficient utilization ofenergy
derived from digested fat as compared to that from
cereal grains and protein sources, and due to the
associated reduction in body heat production, the
inclusion offat in swine diets tends to reduce the
effect ofheat stress on feed intake and animal
performance.
Ingredient
Cereal Grains
Barley
Corn
Oats
Wheat
Fat-rich
Canola seed
Soybean seen
Meat and bone meal
I
As defined by ether extraction.
Percent fat'
2
4
5
2
40
18
9
Table 4-46. Fat Content - Common Feed Ingredients.
Fat can be added to swine diets indirectly, avoid-
ing the need to install expensive fat handling equip-
ment. High fat ingredients such as whole seed
canola or soybeans have been used by many pro-
ducers. Table 4-46 indicates the quantity offat
contained in such ingredients, as compared to
commonly used cereal grains. To add 2% fat to a
diet, canola seed containing 40% oil should be
added to the diet at the rate of50 kg/t (5%). The
same quantity of fat would require I 10 kg/t of
soybeans ( 11%). If such high fat, and therefore
high energy feeds are used. adjustments to the
amino acid content of the diet may be required. For
example, if 2% fat is added to the diet, crude
protein should also increase by about 0.5%.
111

130. The amount of added fat required to adequately
suppress dust has not been determined. A mini-
mum of0.5% has been recommended, although
some producers are adding as much as 2% fat.
Many commercial feed manufacturers have special-
ized fat handling equipment that allows them to add
fat to the outside of the pellet. This has proven to
be effective in reducing visible dust in the barn.
Additional Reading and References
Pettigrew, J.E. and R.L. Moser. 1991. Fat in swine
nutrition. In: (Miller, E.R., D.E. Ullrey and A.J.
Lewis, Ed.). Swine Nutrition. Butterworth -
Heineman, 80 Montvale Avenue, Stoneham, MA
02180, pp 133-144.
Powles, J., J. Wiseman, DJ.A. Cole and B. Hardy.
1993. Effect ofchemical structure of fats on their
apparent digestible energy value when given to
growing/finishing pigs. Anim. Prod. 57:137-146.
Powles, J., J. Wiseman, D.J.A. Cole and B. Hardy.
1994. Effect ofchemical structure offats on their
apparent digestible energy value when given to
young pigs. Anim. Prod. 58:411-417.
Cera, K.R., D.C. Mahan and G.A. Reinhart. 1990.
Evaluation ofvarious extracted vegetable oils,
roasted soybeans, medium chain triglyceride and an
animal vegetable fat blend for postweaning swine.
J. Anim. Sci. 68:2756-2765.
Mineral Ingredients
Minerals are added to the diet when the basal
ingredients fail to meet the requirement of the pig.
Thus, it is rare to supplement potassium or magne-
sium since basal ingredients supply more than
sufficient amounts ofthese nutrients. However,
calcium, phosphorus, sodium and chloride are
routinely added to practical diets. Common mineral
supplements are illustrated in Table 4-47a and Table
4-47b.
Table 4-47. Typical Analysis(%) of Common Mineral Ingredients Used in Swine Diets.
Table 4-47a.
Macrominerals
ingredient Calcium Phosphorus Sodium Chloride Potassium Magnesium
-percent-
Dicalcium phosphate 17.0 21.0 0.6
Monosodium phosphate 26.0 19.0
Disodium phosphate 22.0 32.0
Mono-dicalcium phosphate 15-23 18-27
Deflourinated phosphate 31.0 18.0 5.0
Limestone 38.0 0.2
Salt 39.3 60.4
Sodium Bicarbonate 27.4
Potassium bicarbonate 39.0
Potassium chloride 0.1 1.0 47.0 50.0 0.1
Magnesium oxide 1-6 51-59
Ammonium chloride 65.0
Potassium magnesium sulfate 18.0 11.0
112

131. Table 4-47b.
Microminerals
Ingredient Iron Zinc Copper Manganese Iodine Selenium
-percent-
Calcium iodate 62
E.D.D.I. 80
Copper carbonate 55
Copper oxide 75
Copper sulphate H2
0 25
Ferrous carbonate 36-45
Ferrous oxide 57
Ferrous sulphate H2
0 20-22
Manganese carbonate- 45
Manganous oxide 55-65
Manganese sulphate 27-28
Potassium iodide 68
Sodium selenate 40
Sodium selenite 45
Zinc Oxide 70-80
Zinc sulphate 36
Note: Actu� nutrient composition m�y �· depending on the supplier. Nutrient composition should be confirmed by chemical
analysis. Different sources may vary ID mineral availability, especially for copper and iron. Refer to text for details.
Probiotics
Probiotics are a relatively new concept in the
regulation ofintestinal bacteria. They have been
widely touted as an alternative to the use ofantibi-
otics in swine rations. They are supposed to have
the opposite effect to antibiotics on the intestinal
microorganisms in the digestive tract. Whereas
antibiotics control the microbial population in the
intestine by inhibiting or destroying microorgan-
isms, probiotics actually introduce live bacteria into
the intestinal tract.
Both beneficial and potentially harmful bacteria
can normally be found in the digestive tract of
swine. Examples ofharmful bacteria are Salmo-
nella, Esherichia coli, Clostridium perfingens and
Campylobacter sputorum. Not only can these
bacteria produce specific diseases known to be
detrimental to the host but through competition for
essential nutrients, they can also decrease animal
performance. In contrast to the effects of these
disease causing microorganisms, bacteria such as
Lactobacilli and the vitamin B-complex producing
bacteria can be beneficial to the host. By encourag-
ing the proliferation ofthese bacteria in the intesti-
nal tract, it can be possible to improve animal
performance.
The ideal situation would be to always have
specific numbers ofbeneficial bacteria present in
the intestinal tract. However, physiological and
environmental stress can create an imbalance in the
intestinal flora ofthe tract allowing pathogenic
bacteria to multiply. When this occurs, disease and
poor performance may result. Probiotics increase
the numbers ofdesirable microflora in the gut
thereby swinging the balance towards a more
favourable microflora.
The mode ofaction of probiotics has not been
clearly defined. It has been suggested that
probiotics increase the synthesis of lactic acid in the
gastrointestinal tract of the pig. This increased
production of lactic acid is postulated to lower the
113

132. Table 4-48. Performance of Starter Pigs Fed Diets
Containing a Problotic.
pH in the intestine, thereby preventing the prolifera-
tion of harmful bacteria such as E. coli. The
decrease in the number ofE.coli bacteria may also
reduce the amount of toxic amines and ammonia
produced in the gastrointestinal tract. In addition,
there are reports which suggest that probiotics may
produce an antibiotic-like substance and also
stimulate the early development ofthe immune
system of the pig.
Despite a considerable amount ofstudy, the
research conducted to determine the value of
probiotics in swine diets has been inconclusive.
The results ofone experiment conducted to deter-
mine the effects of probiotics in starter diets are
shown in Table 4-48. The results ofthis experiment
are typical of most ofthe research conducted with
starter pigs, with most researchers reporting slight
improvements in daily gain and feed efficiency as a
result of probiotic inclusion. However, this is not
always the case and several researchers have re-
ported the opposite effect.
Scheuermann. S.E., 1993. Anim. Feed Sci. Technol. 41:
181-189.
0.65
1.04
1.60
0.63
1.05
1.66
0.61
1.02
1.66
Level of Probiotic (cfu/kg)
0 10s ]09 I 010
0.61
1.04
1.69
Daily Gain (kg)
Daily Feed (kg)
Feed Efficiency
Table 4-49. Performance of Growing Pigs (23 -38 kg)
Fed Diets Containing a Probiotic.
The value ofadding probiotics to diets fed to
growing pigs would appear to be questionable
based on experimental data such as that shown in
Table 4-49. Some researchers have speculated that
probiotics may actually have some negative effects
on pig performance during the growing phase by
competing for nutrients with indigenous organisms
of the digestive tract, decreasing carbohydrate
utilization and increasing the intestinal transit rate of
digesta. Therefore. although the theoretical concept
of probiotics appears promising, the documented
evidence oftheir therapeutic value suggests that the
search must continue for a workable alternative to
antibiotics.
ProbioticControl
Average Daily Gain (g) 263 270
Average Daily Feed (g) 599 594
Feed Conversion Efficiency 2.28 2.20
Pollmann et al., 1980. J. Anim. Sci. 51: 577-581.
Probiotic = Probios (MuLabs Division, Pioneer Hybrid
lntemational).
Additional Reading and References
Fralick, C. and T.R. Cline. 1983. The efficiency of
a commercial available probiotic. Purdue Univer-
sity Swine Day. pp. 7-10.
Pollmann, D.S. 1987. Probiotics in pig diets.
Recent Adv. Anirn. Nutr. 13: 193-205.
Some ofthe reasons for the variability ofresults
include the fact that the viability of microbial
cultures may be dependant on storage method,
strain differences, dose level, frequency of feeding,
species specificity problems as well as drug interac-
tions. The difficulty in maintaining a viable
lactobacillus culture in swine feeds may also par-
tially explain the inconsistency in research results.
lt is well documented that temperature, humidity,
change in pH and various antibiotics will decrease
the viability of lactobacillus cultures.
Pollman, D.S.. D.M. Danielson and E.R. Peo.
1980. Effects of microbial feed additives on
performance ofstarter and growing-finishing pigs.
J. Anirn. Sci. 51 :577-581.
Scheuermann. S.E., 1993. Effect of the probiotic
Paciflor (CIP 5832) on energy and protein metabo-
lism in growing pigs. Anim. Feed Sci. Technol. 41:
181-189.
Wren. W.B. 1987. Probiotics: Fact or fiction.
Large Anim. Vet. pp. 28-30.
114

133. Synthetic Amino Acids
Although the most common source of amino
acids in swine diets is complete proteins such as
soybean or canola meals. some can be provided by
individual amino acids that are manufactured by
bacterial culture. The most common example is L-
lysine hydrochloride (HCI). Commercial products
are 98% pure and contain 78.4% lysine in a form
that is essentially 100% available to the pig. Other
amino synthetic amino acids that are available, and
increasingly at competitive prices. include: L-
threonine (98% pure threonine in the product). DL-
methionine (99% pure methionine in the product)
and L-tryptophan (98% pure tryptophan in the
product). There has been some data that suggest
that synthetic amino acids, such as lysine HCI is
used less efficiently than the lysine from soybean
meal when pigs are fed once a day, but there is no
difference at higher feeding frequencies or when
pigs are fed ad libitum.
Synthetic amino acids, and in particular lysine
HCI are sometimes referred to as a growth
promotant. They are not. They are ingredients
which supply the nutrient, lysine. and thus have no
growth promoting properties. Growth may im-
prove with the addition oflysine HCl to the diet if
lysine is deficient. In this case, they merely im-
prove the nutrient balance ofthe diet. Lysine HCI
should only be purchased when it is economical. If
lysine from lysine HCI is less expensive than lysine
from other sources. they are worth considering. If
they are more expensive, the alternative sources
should be chosen.
When large quantities ofsynthetic amino acids are
used it is important to consider the amount of
energy supplied by amino acids as well. Just like in
protein sources, such as canola meal and soybean
meal, amino acids do contribute to the digestible
energy content ofingredients. It can be estimated
that the DE contents of L-lysine HCL, L-threonine,
DL-methioninc and L-tryptophan are 4970, 4250,
5750 and 4900 Kcal per kg ofproduct respectively.
The energy contents ofsynthetic amino will have an
effect on their economic value in feed formulation
systems and on the calculated energy content of
diets that include synthetic amino acids.
Some alternatives to pure synthetic amino acids
are available or will become available in the near
future. Examples are methionine hydroxy analogue
(MHA) and fermentation products that contain high
concentrations ofseveral essential amino acids.
MHA can be used to replace methionine. It is
available in a dry form (calcium - MILA, 93%
MHA) or in liquid form (88% MHA). There is
some controversy about the amounts of amino acids
that are effectively supplied by these alternative
products. For example, some research with poultry
would suggest that MHA is approximately 75%
effective in supplying methionine as compared to
pure synthetic CL-methionine. Only a limited
number have been conducted to study the effective-
ness ofthese alternative sources of amino acids in
swine diets.
Interestingly, as these amino acids become more
economical, they provide another alternative to
balancing swine diets. Rather than only selecting
among the various protein meals, the opportunity
will exist to consider the synthetic or free amino
acids as another option. However, as diets change to
include greater quantities offree amino acids in
place ofcomplete proteins, the need to carefully
formulate and manufacture diets will increase. The
room for errors will shrink because the over-
formulation ofthe past will be replaced by greater
precision. Eliminating wasteful excesses will be of
great benefit to the industry, but it carries a signifi-
cant price tag in terms ofquality control.
Organic Acids
Organic acids are widely utilized to inhibit mold
activity in stored feedstuffs as well as finished feed.
By treating with organic acids, it is possible to
harvest and store grains at a higher moisture content
without spoiling. Propionic and acetic acids are the
most commonly used acids for this purpose.
Some of the early research conducted to deter-
mine the nutritional value ofacid-treated grains
observed improvements in pig performance which
could not be attributed solely to the antifungal
properties ofthese acids. Therefore, a considerable
amount of research has been conducted to try and
improve rate ofgain and feed efficiency through the
use oforganic acids.
115

134. Most ofthe research conducted with organic acids
has been focused on improving their performance
ofstarter pigs using fumaric, citric or propionic
acid. Supplementation with organic acids at levels
between 0.5 and 3.0% ofthe total diet has been
shown to consistently improve feed efficiency while
having little or no effect on growth rate. Typical
research data is presented in Table 4-50.
Table 4-50. Effect Of Organic Acid Supplementation On Starter Pig Performance.
Diet pH
Average Daily Gain (g)
Average Daily Feed (g)
Feed Efficiency
Control
5.78
254
494
1.94
Propionic
Acid (2%)
4.71
245
440
1.79
Fumaric
Acid (2%)
4.18
263
480
1.83
Citric
Acid (2%)
4.06
258
471
1.82
Adapted from Giesting and Easter, 1985, J. Anim. Sci. 60: 1288-1293.
The mechanism by which the beneficial effects of
organic acid supplementation are achieved has not
been determined. However, it has been suggested
that the reduction in dietary pH may increase the
activity ofpepsinogen, a pH-sensitive, protein
digesting enzyme in the stomach. The reduction in
dietary pH may also reduce gastric pH resulting in
greater bacteriocidal activity in the stomach, thus
reducing nutrient-robbing bacterial loads in the
intestinal tract. Organic acids may also act as
chelating agents which increase the absorption of
minerals in the intestine ofthe pig. Finally, it has
been suggested that the reduction in pH may slow
gastric emptying, allowing greater time for
proteolysis (digestion ofprotein) to occur in the
stomach.
As pigs age, their ability to produce their own
gastric acid is increased and therefore, there is little
benefit in terms ofgrowth rate or feed efficiency
from supplementing the diets ofgrowing pigs with
organic acids. However, it may be possible to
improve carcass traits through organic acid supple-
mentation.
Recent evidence has suggested that methylmalony
CoA, a breakdown product of propionic acid
metabolism, inhibits some ofthe enzymes involved
in fat synthesis. As a consequence, pigs fed high
levels (3-9%) of propionic acid have been shown to
have significantly lower levels of backfat than
control pigs. Therefore, ifthe current consumer
demand for reduced carcass backfat continues,
propionic acid supplementation ofdiets fed to
market hogs may increase in the future.
Feed Flavours
The use offlavors in animal feeds has increased
considerably in the past decade as more attention is
being paid to ingredient and diet palatability. This
increase in feed flavour usage has been paralleled
by a dramatic increase in the number ofcommer-
cially available products ranging from simple spices
and tonics to aroma modifiers, sweeteners, flavour
intensifiers and artificial flavors.
Unfortunately, feed flavors tend to be incorpo-
rated into swine feeds because ofmarketing appeal
and consumer preference rather than as a result of
proven effectiveness. At present, very little is
known about what specific flavors pigs find attrac-
tive and too often flavors are chosen for inclusion in
swine feeds because they are attractive to the human
palate rather than that of the pig. Even if a particu-
Jar flavour has been shown to be preferred by swine
in free choice or stimulus tests, this preference will
not necessarily result in improved performance.
The end result is that although there are claims
that such products will stimulate feed intake, very
few studies have demonstrated a consistent
116

135. improvement in feed intake or growth rate as a
result ofthe inclusion of feed flavors in the diet.
One researcher compared 129 different feed flavors
to determine which specific flavors were preferred
by pigs. Five ofthe flavors which were shown to
be most preferred by pigs were then used in a
feeding trial. None of the flavors significantly
increased the feed intake or growth rate ofstarter
pigs. Since there is a cost associated with the
inclusion offlavors in the diet, it would be wise to
avoid their use until further research is conducted
and a more consistent response is obtained.
Additional Reading and References
McLaughlin, C.L., C.A. Baile, L.L. Buckholz and
S.K. Freeman. 1983. Preferred flavours and
performance of weaniling pigs. J. Anim. Sci.
56: 1287-1293.
117

136. 118

137. 5. DIET FORMULATION
Diet formulation is the process of matching the
pig's nutrient requirements with the nutrients
supplied by available ingredients. in the most
economical manner possible. The process sounds
simple enough, but do not be misled. As explained
below, nutrient requirements vary among animals
and farms. Over-formulation may seem to be a
logical way to ensure the animal's requirements are
met, but this is costly in both financial and environ-
mental terms. Similarly, defining the nutrients
supplied to the pig by various ingredients stills lacks
the precision that many ofus seek and again, being
too conservative in assigning specifications to
various ingredients wastes money and nutrients.
finally, linking the process to net income, while
essential, requires a firm understanding ofthe
relationship between nutrient supply and animal
performance. So, while the process ofdiet formula-
tion sounds simple enough, it is anything but.
Overall, diet formulation needs to be viewed as a
means to an end. The 'end' is efficient production
resulting in a final pork product ofhigh quality.
Following five basic steps breaks ration formulation
down into simpler components that increases the
likelihood ofsuccess. Diet formulation, and the
development ofassociated feeding programs. is
merely one component - albeit an important one - of
the overall pork production system.
I.Objectives
2.Re�iremerrt's
3.Iqgredients
4.Formu/ations
FIVE STEPS IN SWINE DIET
FORMULATION
Define Objectives
Establish Requirements
Select and Characterize Ingredients
Formulate Diets
Evaluate Diets
Define Objectives
The first step in developing a feeding program is
to define the objectives; these will include the
objectives ofthe overall business, ofthe pig unit
within the overall business and of individual pigs
within the pig unit. Consequently, the nutritionist
and the pork producer must communicate to ensure
they are both working towards the same
objective(s). Following are some typical objectives.
It is clear from the following list that "make the
most money," as noble (and essential) objective as it
may be, is not sufficiently precise!
Maximize Net Income per Pig Place
A pig place is the barn area occupied by a single
pig. In a grower barn, a pig place will turn over
approximately three times per year; in a nursery,
turnover will occur every 5 to 6 weeks, or about 10
times per year. By expressing net income on a 'per
pig place' basis, the importance ofgrowth rate, and
thus of barn throughput, is recognized. Expressing
net income on a 'per pig' basis assigns much Jess
emphasis to barn throughput. Therefore, this
objective will be most appropriate where capital
costs are high and capital debt exists. lfbarn
throughput increases, fixed costs can be spread over
more animals.
In a typical commercial circumstance, the only
instances in which one would not want to maximize
net income per pig place would be when housing
space is not limiting, when market prices do not
119

138. cover variable costs or when animals are not
available to keep the barn full at all times. In the
vast majority ofcircumstances, a farm's
profitability will be maximized when farrowing
crates, nursery pens and growout facilities are kept
filled to their maximum capacity.
Maximize Net Income per Pig Sold
Jn some instances, such as when housing space is
not limiting or when the supply offeeder pigs is
limiting, the focus of management will shift from
net income per pig place to net income per pig. For
example, feeding programs can be designed to
move pigs through a barn more quickly. Such diets
will tend to be more costly, but if there are no
additional pigs to replace those which have moved
on to market, the only opportunity to recover the
extra feed cost is through reduced inventory costs,
such as interest on the operating line ofcredit.
To Maximize Animal Performance
While most commercial farms will focus on
maximizing net income, certain types offarms,
notably those involved in genetic selection
programs, will seek to maximize animal
performance. This ensures that nutrient intake is
not confounding selection of animals based on
genetic merit. Purebred or nucleus breeding units
will typically fall into this category.
Under commercial conditions, producers may
choose to feed some animals a 'non-limiting' diet to
determine the maximum potential ofanimals under
their particular conditions. For example. the impact
ofhousing, genetics and health can only be
determined when nutrient supply is not limiting
animal performance.
To Maximize Profits for the Total Farming Unit
Ln many cases, the pork production unit is associ-
ated with other farming enterprises, such as crop
production. In this case, the relationship of the pig
barn to the other enterprises must be considered.
For example, the pig unit may be used to convert
certain crops into a more saleable or valuable
commodity - pork. In some situations, this could
lower profitability ofthe pig unit, but maximize the
net income ofthe total farm. An example could be
the use of lower quality cropping products that
lower animal performance but convert a commodity
that is unsaleable into one which is more easily
sold.
To Minimize the Impact on the Environment
In Canada, as elsewhere, the impact ofpork
production on the environment is under increasing
scrutiny. For example, the spreading ofslurry
places a nutrient load on the land. While this may
be desirable in most cases, due to fertilizing and soil
conditioning value, ifcertain conditions exist, it can
lead to a portion ofthe nutrients entering nearby
lakes and rivers due to runoff. Because diet
composition affects slurry composition, individual
pork producers may manipulate nutrient loading of
the soils in a way that is appropriate for their
particular circumstances. Ofcourse, following
good management practices for slurry handling
would be assumed to be the most important first
step in all cases.
To Produce a Carcass Possessing Certain Traits
Production systems that link animal production
with the packing industry, through either contract or
ownership, increases the opportunity to develop
pork products possessing certain traits. This might
be related to product uniformity, product quality or
possibly even more specific traits such as fatty acid
profile or "organic" designation. In some ofthese
instances, diet plays a central roll in achieving the
desired final product.
120

139. To Establish a Production System that
Emphasizes Animal Well-being
Animal well-being is difficult to define, let alone
measure, but it is a subject that is attracting greater
interest both within and outside the pork industry.
Animal well-being is not necessarily impaired by
maximizing net income; indeed, profitability and
welfare should not be considered as mutually
exclusive. Nutrition is rarely associated with
violations ofanimal well-being, other than cases of
outright neglect leading to malnutrition and/or
starvation. However, this may change as we learn
more about basic animal behaviour. Scientists and
producers continue to work on providing the pig
with the most positive environment while still
maintaining a satisfactory profit margin.
From this list, it is clear that the nutritionist's
focus will vary among farms. Depending on the
circumstances, it may be the carcass, the pig, the
barn, the total agri-business ofwhich pork produc-
tion is only one part, or the environment. In actua1
practice, nutritionists will consider all ofthese
objectives and vary the emphasis depending on the
individual client and his or her particular situation.
Define Requirements
Once the nutritional objectives have been set, the
next step is to define the nutrient intake required to
achieve them. Nutrients required by the pig depend
on many factors that are internal (i.e. genotype, age,
sex, expected level ofproductivity) or external (i.e.
thermal and social environment, economic condi-
tions) to the pig. Consequently, these must be
considered in establishing the nutrients required in a
given diet.
In addition, total daily feed intake must be
considered because, in fact, nutrients are required
on a daily intake basis. This applies to both the
breeding herd and market hogs. Unfortunately,
there is a poor understanding offeed intake. Efforts
to predict intake are limited in scope and few
operations measure it directly. Consequently, while
we recognize that nutrient requirements should be
expressed on a daily intake basis, in practice they
are presented on the basis ofdietary concentration.
Intake will be discussed in more detail under
chapters dealing with the feeding ofspecific classes
ofswine.
Nutrient requirements can be established using
two approaches. The more traditional system is the
empirical method which employs experiments to
measure the pig's response to diets of differing
nutrient supply. This method has the advantage of
employing actual animal response in the evaluation,
but often fails to explain why the response was
observed. This makes it difficult to extrapolate the
results to production circumstances which may
differ among farms, due to genetics, environment,
or management.
The second approach, the factorial method,
attempts to identify the various functions within the
animal that require a given nutrient and define the
needs based on each. For example, energy is used
for maintenance, growth, pregnancy, and lactation.
By expressing the requirement for energy on the
basis ofits use for each process, and incorporating
some relationship between requirement and rate of
production, one can estimate the pig's requirement
for energy for various levels ofperformance. By
adding factors that address energy needs for
externa1 forces, such as temperature and level of
activity, energy requirements can be predicted -
theoretica1ly. The accuracy of such predictions, of
course, depends on the precision ofthe various
prediction equations.
Typically, nutritionists use both approaches, with
the factorial method increasing in popularity due to
the need to define requirements under diverse
conditions. However, even where the factorial
method is predominant, animal experiments will
still be employed to confirm the accuracy ofthe
prediction equations.
Nutrient requirements that are published, for
example, by the National Research Council (NRC)
or the Agriculture Research Council, are by and
large those required to maximize performance.
Clearly, if performance somewhat below maximum
is the most economical, then the nutrient levels
needed may also be somewhat less than those
121

140. published. Given the information available, one can
develop at least a rough estimate ofthe
requirements needed for a given circumstance.
The graph in Figure 5-1 illustrates the general
approach to defining the pig's requirement for a
nutrient. It shows that as the amount ofnutrient
being tested is increased in the diet, the pig
responds in some way, such as by growing faster, or
more efficiently, or by producing bigger litters.
When the diet is very deficient, small additions of
the limiting nutrient give a large improvement in
performance. However, as the requirement is
approached, the response of the pig to each unit of
nutrient becomes less. This is sometimes called the
law ofdiminishing returns. It is clear from this
figure that the greatest return per dollar spent does
not occur near the peak ofthe curve. Depending on
the marketplace, it may or may not be economical
to provide full supplementation. Again. the
factorial approach to defining nutrient requirements
is the most adaptable to such changes in expected
levels of productivity.
constant from year to year, or even from farm to
farm. They need to acknowledge the specific
economic circumstances and respond in an appro-
priate manner. Simply stated, there is no feeding
regime that is best under all circumstances.
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NUTRIENT CONTENT OF THE DIET
The process can be complicated by mitigating
circumstances, such as the genetic quality ofthe
animals, the management style of the farmer, the
financial status ofthe farm, the environmental
conditions in the barn, and so on. The more we
learn about the science ofnutrition, the better we
will be able to tailor diets to the specific needs of
individual farmers. This is one aspect ofswine
nutrition which has advanced the most in the past 5
years, and further progress is expected. "Situation
dependent feed formulation" the process whereby
feeding programs are optimized for each production
system is a major objective if one wants profits to
be maximized and the industry as a whole posi-
tioned to compete most effectively in the market-
place for the consumers' dollar.
Select and Characterize Ingredients
Once the objectives ofthe feeding program have
been established, and the nutrient requirements
defined, the next step is to select the ingredients
available and determine their nutrient content.
Figure 5-1. Determination of a Nutrient Require-
ment, Showing the Pig Response to Increasing
Nutrient Supply.
For example, when feed is inexpensive and hog
markets are strong, feeding the highest quality diet
may be the most economical for most farmers.
However, in the opposite situation, when feed is
expensive and markets are weak, a less ambitious
diet would likely be more profitable. It becomes
readily apparent that feeding regimes should not be
122

141. Selecting ingredients is not a difficult task, as they
are usually the ingredients at hand. However.
advantages may be gained by seeking out less
common ingredients that represent good value and
can be successfully integrated into a swine feeding
program. A review of ingredients in Chapter 4 may
be helpful in this regard.
Determining the nutrients supplied by the ingredi-
ents is much more difficult, involving essentially
two steps: determining the nutrient composition of
the ingredient and determining the availability to the
pig of those nutrients. While a more thorough
discussion of this subject appears in Chapter 3, a
few ofthe more pertinent points will be swnma-
rized below.
The best method ofdetermining nutrient
composition is chemical analysis. The most
important analyses required on cereal grains and
protein meals (canola meal, soybean meal) are
crude protein, calcium and phosphorus. Ifmoisture
problems are suspected, dry matter analysis should
also be requested. While chemical assays are
relatively easy and inexpensive for common
nutrients, they are more expensive and time
consuming for nutrients like amino acids and
vitamins. Therefore, in the interest of time and
economics, amino acid levels are estimated from
protein content (see chapter 3) or book values are
employed, ifavailable. For the most part. these
approaches are adequate. However, if book values
are used, the variability of the ingredient must be
acknowledged, as individual samples rarely reflect
the average.
Crude protein is an indirect measure ofprotein,
based on the amount of nitrogen in a feedstuff.
Since most ofthis nitrogen is present as protein, this
information is used to estimate actual protein. On
average, most proteins in grain and vegetable
protein sources contain about 16 percent nitrogen.
Thus, ifone knows the nitrogen content. multiply-
ing this value by 6.25 (100 + 16 = 6.25) will esti-
mate protein (refer to pages 71-74 for more detail).
Once total nutrient content is established, then the
availability ofthose nutrients to the pig must be
considered. This approach is universally applied in
the case of energy, where digestible or
metabolisable energy are always used in place of
gross energy; however, for amino acids and
minerals, availability is considered less often, a
situation which we believe to be most unfortunate.
Availability cannot be determined directly on
individual samples without using animal tests.
Since this is expensive and far too time consuming,
indirect methods, such as Near Infrared
Spectroscopy (NTR), where available, or book
values, must be employed.
There are other considerations as well. First, it
must be remembered that the grading system for
grain was designed to satisfy the needs ofan export
market and for the milling industry, rather than to
meet the needs ofthose in the livestock industry.
Thus, many ofthe factors that cause downgrading
of grains are of little or no consequence to animal
nutritionists.
A case in point is bushel weight. Although very
low bushel weight may be reflected in lower energy
content. a wide range is perfectly acceptable to the
pig. Table 3-5 outlines minimum acceptable bushel
weights for swine diets. Values below the minimum
are still acceptable, but some lowering ofestimated
energy content would be advised. Refer to chapter
3 for details.
Visual appraisal, although subjective, should not
be underestimated. Freedom from weed seeds,
especially those that are unpalatable or toxic, is
obviously very important. Sprouting, mold or
contamination are other things to watch for.
Diet Formulation
Once the nutritional objectives have been
established, the requirements identified and the
ingredients selected and characterized, the next step
is to put this information together into a formula
that can be used to make the diet. This can be done
using any one ofat least three methods:
1. Linear programs (computer formulation)
2. Algebraic formulas
3. Pierson's Square
123

142. 1. Linear programs
The speed and simplicity of computer formulation
of diets makes it the most effective and popular
method for anyone involved in the process on a
regular basis. Rather than use the more simplistic
and slower algebraic methods or Pierson's Square,
the computer can handle many simultaneous equa-
tions in a fraction ofa second. Because of this
speed and simplicity, the computer allows nutrition-
ists to consider more ingredients and more nutrients,
and pay far greater attention to cost than would
otherwise be the case. However. it is important to
remember that the information generated by a
computer can be no better than the information
provided to it initially!
Essentially, the computer takes the nutrients
needed by the pig on the one hand, and the nutrients
supplied by available feedstuffs on the other, and
combines them to develop a balanced ration at the
least possible cost. Computer ration formulation
programs use a linear equation (thus, linear
programming) such as:
Requirement= aX I + bX2 + cX3 + dX4
where a, b, c and d are the amounts ofeach offour
ingredients in the diet and X1, X2. X3 and X4
represent the amount ofthe nutrient in question
present in each ofthe four ingredients.
Recently, feed formulation programs have be-
come much less expensive for producers to pur-
chase. These programs are much smaller than those
used by major feed companies, but they will permit
simultaneous formulation ofa diet considering 50
or more nutrients supplied by 50 or more ingredi-
ents. This is clearly more than the average pork
producer requires!
There is some question whether the individual pork
producer really needs such capability. Is it worth the
money to purchase such programs? The answer lies
not in the cost ofthe program, but rather in the time
and expertise required to operate it. Errors related to
ingredient composition or nutrient requirements can
lead to disastrous results. For the most part, diet
formulation should be left to professionals with the
training and experience required to develop a feeding
program that best meets the producer's needs.
Ongoing least cost formulation ofdiets to ensure that
feed costs are truly minimized can be carried out on
the farm with little risk, provided a nutritionist has
been involved in defining the restrictions included in
the formulation program.
Table 5-1. TypicaJ Ingredient Output From A Feed Formulation Program.
Formula Price
Ingredients Actual Minimum Maximum Low Actual High
Barley 34.35 1.13 l.30 1.60
Wheat 36.10 40.0 1.43 1.70 1.95
SBM (47%) 11.80 2.52 2.85 3.36
Canola Meal 15.00 15.0 1.80 2.00
Dicalcium phosphate 0.69 4.30 77.69
Limestone l. l 3 0.61 12.15
Salt 0.33 0.55
Mineral Premix 0.30 0.30 5.20
Vitamin Premix 0.30 0.30 15.00
Total 100.00 176.55
124

143. Tables 5-1 and 5-2 outline the type of information
provided by a computer-based feed formulation
program. In Table 5-1, the ingredient summary
itemizes the ingredients selected and the amount
required in the diet. Limits (maximums and
minimums) that were set up in the original feed
specifications are also shown. It can be seen in the
example that canola meal was priced competitively,
because it went to its upper limit. The premixes are
obviously expensive, because they are at their lower
limits. The output often also tells the formulator
how competitive the price for each ingredient is.
For example, soybean meal would have to drop to
$252 per tonne in order for more soybean meal to
come into the formula. Likewise, ifthe price rose
to $336, the computer would select less soybean
meal. There is no lower price limit for canola meal,
since it is already using the maximum amount.
Wheat appears to be competitively priced, since it is
very close to its lower price limit and much cheaper
than its upper price. Thus, programs ofthis nature
can be used to determine the value ofcertain
ingredients in various diets used on the farm.
Table 5-2 provides a somewhat similar summary
for nutrients (as opposed to ingredients). Nutrients
that are at their lower limit are forcing the cost of
the diet up. For example, digestible energy, lysine,
sodium, calcium and phosphorus are all at their
lower limit, meaning that ifany ofthese could be
lowered, the cost of the diet would be reduced.
However, since animal performance might suffer,
reducing the diet cost would not necessarily save
money in the long run.
Table 5-2. Typical Nutrient Output from a Feed Formulation Program.
Nutrient Requirements Constraint
Actual Minimum Maximum Unit Cost Increment Decrement
Digestible energy 3200 3200 0.001 111.753 117.608
Protein 19.93
Lysine 0.95 0.95 0.96 5.302 2.908
Methionine 0.34 0.29
T.S.A.A. 0.74 0.57
Tryptophan 0.24 0.18
Threonine 0.73 0.59
Isoleucine 0.81
Sodium 0.15 0.15 0.25 0.008 12.914 0.825
Chloride 0.27 0.15
Calcium 0.75 0.75 0.80 0.008 12.430 4.248
Phosphorus 0.60 0.60 0.70 0.026 5.099 1.455
Available phosphorus 0.36
125

144. 2. Algebraic Formulas
ln the absence of computers, sometimes simple
calculations arc required to balance a simple ration
involving only a few ingredients. In such cases,
algebraic methods arc often selected because they
arc more accommodating. However, for those not
comfortable with algebra, they may be a bit confus-
ing at first. Following is an example:
EXAMPLE
Problem: Formulate a diet to contain 0.78 percent
available lysine using five ingredients: barley,
wheat, soybean meal, canola meal and premix.
Canola meal is assumed to contain l .45 percent
available (ileaJ) lysine and is fixed at IO percent of
the diet, the premix, containing no lysine, is fixed at
3.5 percent ofthe diet and wheat, with 0.31 %
available lysine, is set at 25 percent ofthe total diet.
The barley contains 0.29 percent available lysine
and the soybean meal 2.7 percent available lysine.
So far, the diet looks like this:
Barley ?
Wheat 25.0
Soybean meal ?
Canolameal 10.0
Premix 3.5
TOTAL 100.0
Solution:
i) With the wheat and canola meal fixed, this diet already
contains 0.22 percentage (.25 * 0.3 l + .10 * 1.45 = 0.22)
points ofavailable lysine. Thus, the barley and the
soybean meal must provide 0.56% available lysine and do
so in 61.5 percent of the total mix ( JOO minus 25.0 minus
10.0 minus 3.5 -61.5).
ii) Let "X" equal the proportion of barley in the diet
and let "61.5 - X" equal the portion ofsoybean
meal in the diet. The amount ofavailable lysine required
will be 0.56 percent (0.78 minus 0.22).
iii) The amount ofavailable lysine supplied by barley will
be .0029X (Xis the amount of barley and .0029 is the
portion of barley that is lysine - that is 0.29%) and the
amount ofavailable lysine supplied by soybean meal will
be .027(61.5-X). Thal is, the amount of available lysine
in soybean meal times the amount of soybean meal in the
diet.
Thus, the algebraic equation to solve the problem will be:
.0029X + .027(61.5-X) = 0.56
The equation will solve as follows:
.0029X + 1.6605 - 0.027X = 0.56
-.0241X=-l.1005
X =45.7
Therefore, the amount of barley in the diet will be 45.7
percent and soybean meal will make up 15.8 (i.e. 61.5 -
45.7) percent. The final formula will thus look as
follows:
Barley 45.7
Wheat 25.0
Soybean meal 15.8
Canola meal 10.0
Premix 3.5
TOTAL 100.0
The algebraic method is adaptable to many kinds of
calculations. However, for many ofus, algebra is a
long forgotten subject; for this reason. the algebraic
method is not very popular.
3. Pierson's Square
Pierson's square is an established method that is
popular due to its simplicity. However, its simplic-
ity is also its weakness; it functions well only in
very simple diets. It is best used in diets containing
only two ingredients. For more complex situations,
other methods are preferable.
EXAMPLE 1
Problem: Formulate a diet containing 16% crude
protein, 0.90% calcium and 0.75% phosphorus,
using barley and a 40% hog supplement.
Solution:
i) The barley was analysed, and found to contain I 0%
crude protein, 0.05% calcium and 0.29% phosphorus.
The hog supplement, according to the label, contains
40% crude protein. 4.3% calcium and 2.6% phosphorus.
ii) Determine the proportion of barley and supplement
needed to provide 16% crude protein in the final mix,
using Pierson's Square.
126

145. Barley
Supplement
10 24
/16
/40 6
30
80%
20%
Fortunately, the diet works out, such that the cal-
cium and phosphorus supplied by the supplement
and the barley provides exactly the amounts re-
quired in the final mix. This may not always be the
case. However, one cannot formulate the diet solely
on the basis ofprotein and select the amount of
supplement so dictated. The feed manufacturer
assumed a certain rate ofuse when the supplement
was formulated. This add rate will therefore supply
the amino acids, vitamins and minerals required.
However, if less or more of the supplement is used,
errors in other nutrient levels may result. Thus, the
manufacturer's recommendations for inclusion
should be followed within 2-3%; ifthis is not
acceptable, a special supplement may be required.
Pierson's Square is used as follows. Place the percent
protein adjacent to the ingredient and the desired level in
the centre of the square. Subtract in the direction of the
arrows (i.e. 16 - 10 = 6 and 40 - 16 = 24). Sum these
two values to get 30 (i.e. 24 + 6 = 30). Divide 24 by 30
to get the percentage barley in the diet and 6 by 30 to get
the same information for the supplement.
This method can, in fact, be used for any nutrient, not
just crude protein.
iii) Now that the proportion of barley and supplement
needed to meet the crude protein requirement have been
determined, the next step is to balance for calcium and
phosphorus. This can be accomplished by completing
Table 5-3.
The Pierson square method can be used for some-
what more complicated formulations, as shown by
example 2, a diet with three ingredients: barley,
soybean meal and premix.
EXAMPLE2
Item Barley Supp. Diet
Problem: Formulate a diet containing 16 percent
protein, 0.90 percent calcium and 0.75 percent
phosphorus using three ingredients: barley, soybean
meal and premix.
Table 5-3. Diet Composition from Pierson Square
Calculation.
Percent in diet
Composition, %
calcium
phosphorus
Supplied to diet, %
calcium
phosphorus
0.05
0.29
0.04
0.23
4.3
2.6
0.86
0.52
100
0.90
0.75
Solution:
i) The barley has the same analysis as that used above,
the soybean meal was analysed and found to contain
46.5% crude protein. 0.25 percent calcium and 0.61
percent phosphorus and the premix, according to the
label contains no protein, 26 percent calciwn and 14
percent phosphorus.
ii) Set up the Pierson's Square as shown. Since the
premix is added according to the label at the rate of 3
percent of the total mix, then the barley and soybean meal
must be proportioned to supply 16% crude protein in the
total mix, which in effect is diluted 3 percent by the
premix. Thus, the percent crude protein in the
barlcy:soybean meal mix must be adjusted upwards by 3
percent. Thus, the 16 percent value in the centre is
adjusted to 16.5 ( 16.0/0.97 - 16.5).
127
The calculations go as follows:
Barley represents 80% of the mix and contains 0.05%
calcium, while the supplement represents 20% of the mix
and contains 4.3% calcium. The total calcium in the diet
will therefore be 80 percent of0.05 + 20 percent of 4.3
(.80 x 0.05 + .20 x 4.3 = 0.04 � 0.86 = 0.90). A similar
calculation can be made for phosphorus.
80 20

146. Calculating as above, the formula for the diet will be:
Barley 79.7
Soybean meal 17.3
Premix 3.0
100.0
The calcium content ofthis diet will be
(.797 x 0.05 + .173 x 0.30 + 0.03 x 26.0) = 0.83 % and
the phosphorus content (.797 x 0.29 + .173 x 0.61 + 0.03
x 14.0) = 0.76%. These are both close enough to the
expected values.
three steps in the process: sampling, mixing and/or
formulation. It is also possible that an error could
have occurred in the laboratory. For this reason,
samples sent to the lab should be split and a dupli-
cate sample retained for later reference. Some
producers will send duplicate samples to two
laboratories, particularly ifa definite answer is
required and lab error needs to be eliminated.
However, ifwell-run laboratories are used, lab
errors should be minimal.
Quality control, that is the actual chemical analysis of
mixed diets, is required to ensure the adequacy ofall
diets fed to pigs.
17.8%
82.2%Barley 10 30
�/16.5
ISoybean meal 46.5 �
36.5
This approach can be extended, for example, to
situations where both wheat and barley are being
used, by using a composite protein content for the
grains in place ofthe barley value used above. In
the case of a 50:50 mix of wheat and barley, con-
taining 13.5% and 10% protein, respectively, a
value of 11.75% would be used in place of the 10%
value for barley in the above examples.
The proportions for each ingredient relate to the 97% of
the diet that will be barley and soybean meal. They must
be adjusted to fit the final diet as follows:
Barley 82.2 x 0.97 = 79.7%
Soybean meal 17.8 x 0.97 = 17.3%
Evaluating Diet Quality
Once diets have been manufactured, there is only
one way to know if the diet was mixed correctly. A
feed sample must be submitted for chemical analy-
sis (crude protein, calcium, phosphorus, salt). The
results of the analysis can be compared to the
expected values. lfthey are within a tolerance
range ofapproximately 5-7% for crude protein (eg:
a 16% protein diet should fall within the ranges of
15.2 to 16.8%) and 10-15% for minerals such as
calcium, phosphorus and salt, one can be assured of
ajob well done. Ifthe results are outside this range
however, there is a problem and the cause must be
determined. lt may have occurred at any of the
Collecting samples ofdiets or ingredients must be
done correctly ifthe analytical results are going to
truly reflect the actual composition. Grain should
be sampled from a bin using a grain probe, selecting
no less than 20 subsamples from different locations
that can be mixed together and submitted as a single
representative sample. Ifa probe is not available, at
least 20 grab samples should be obtained from
different locations. Care must be taken in sampling
below the surface of the standing sample.
For diets, a minimum of 20 subsamples should be
colJected from the holding bin or from at least 6
different feeders in the barn. These should be
thoroughly mixed together into a single composite
sample before sending to the lab.
128

147. Mixed feed can be sampled from a number of
feeders in the barn or as the feed is mixed. The key
is to get a truly representative sample of the mate-
rial. Note that iffeed is collected from the feeders,
poor analytical results may be caused by separation
during handling and delivery, rather than by mixing
or formulation errors. These samples should be
thoroughly mixed before submitting them to the lab
to ensure a good representative mix. Ifseparation
is being investigated, then they should not be mixed,
but sent as individual samples to the lab.
Producers should check the calibration of their
mill to ensure that no errors have been made and
also the formulas for their diets to ensure that they
are correct. Table 5-5 illustrates how to determine
the quantity ofa nutrient in a diet. The mix size is
first corrected to 100. The nutrients supplied by
each ingredient can then be easily calculated by
multiplying the concentration of nutrient in each
ingredient by the amount of ingredient in the feed.
The amounts supplied by each ingredient arc added
together to get the total quantity of nutrient in the
feed.
Table 5-4. Recommended Schedule for Feed Testing on a Farm Manufacturing Three Diets.
Month Sample
Ingredients Feeds
Home Grown Purchased Starter Grower Sow
Jan c c c A
Feb c c A c
Mar c A A c c
Apr c c c A
May c c A c
Jun c A A c c
Jul c c c A
Aug c c A c
Sep A (new crop) A A c c
Oct c c c A
Nov c c A c
Dec c A A c c
C: Collect and retain sample; analyse only ifproblems are suspected. Ifthere are no problems, retain sample in a
cool, dry, dark location for one year and then discard. In this way, ifa problem occurs later, these samples will be
available for use.
A: Collect and analyse. In addition to this, twice a year samples should be selected from three or four different
feeders in each of the three to four sections ofthe barn. Analyse each sample to determine if separation is occurring.
Table 5-4 provides a recommended schedule for
feed sampling and testing on a farm where three
diets are being manufactured. The schedule as-
sumes that no problems are detected. If there is a
problem, more intensive testing will be needed
until the problem is resolved.
The diet in Table 5-5 is well-balanced with respect
to lysine, calcium and phosphorus. Assuming that
unusual ingredients are not used and that the premix
is correctly formulated, ifthese three nutrients
(lysine, calcium, phosphorus) are correct, the rest of
the diet will likely be acceptable. It would not be
necessary to check each and every nutrient in the
diet.
129

148. Ifproblems in the feed analysis are discovered, it
is important to check other sources oferror such as
sampling or analysis before adjusting the mill. If
mill calibration is the problem recalculate the diet
and adjust the mill according to the revised formula.
It is imperative that the mill is not adjusted by 'one
or two clicks' to compensate for excess protein. If
this practice is common, it will not be long before
the mill is totally out ofcalibration and serious
errors will result.
In summary, ifone obtains poor results from an
analysis, then the lab, the formula, the mill, the
delivery system and the method ofsampling can all
be potential sources of error and should be re-
checked. A flow chart summarizing the above
procedures appears in Figure 5-2.
Table 5-5. Calculation of the Theoretical Nutrient Composition of a Feed.
Ingredient Lysine Calcium Phosphorus
Ingredient Diet Ingredient Diet ingredient Diet
Barley 44.3 0.39 0.173 0.07 0.031 0.29 0.128
Wheat 40.0 0.39 0.156 0.04 0.016 0.34 0.136
Soybean meal 11.0 3. 15 0.347 0.26 0.029 0.60 0.066
Canola meal 1.7 2.02 0.034 0.65 0.011 1.07 0.018
L-lysine HCI 0.2 78.40 0.157
Premix 3.0 26.00 0.780 14.00 0.420
TOTAL 100.0 0.866 0.867 0.769
The diet contains the proportions ofingredients shown expressed as parts per I 00. Example: the lysine supplied by
barley will be 0.443 x 0.39 = 0.173.
HAVE THE DIETS BEEN ANALYSED?
YES ------- NO
I I
ARE THE RESULTS ANALYSE DIETS
SATISFACTORY?
I
YES ------- NO
I I
REPEAT SAMPLING REPEAT SAMPLING
AND ANALYSIS AND ANALYSIS
NEXT MONTH IMMEDIATELY
r
I
ARE THE RESULTS
SATISF�CTORY? ------,,
'---------- YES
�----- NO-------,
QUALITY
CONTROL
PROCEDURES
ON THE FARM
HAVE THE INGREDIENTS
BEEN ANALYSED?
I I
NO YES
ANALYSE __j
INGREDIENTS
IS THE MILL
PROPERLY CALIBRATED?
I I
YES NO
ARE THE DIETS
PROPERLY FORMULATED?
I I
YES NO
I I
REPEAT SAMPLING REFORMULATE DIETS
AND ANALYSIS OF INGREDIENTS
Figure 5-2.
130

149. Conducting a Feeding Trial
Producers often need to compare two or more
feeds in terms of performance and profitability.
The best way to compare feeds is to conduct a
feeding trial in which the growth rate and feed
efficiency of the pigs on various diets can be
compared. The trial must be carried out properly if
the results are to be meaningful. The comparison
cannot have biases that might favour one diet over
another. Provided these precautions are taken, one
can be reasonably assured that the differences
observed are due to the diets used in the test and not
due to an outside influence. The following are
guidelines that will help ensure an effective
comparison:
l. Split litters among the various diets being tested.
The effect of litter and genetics can be very large.
especially in starter trials.
2. Use more than one pen per diet even through it
increases the workload. If only one pen is used, the
results in favour ofone diet or another could very
likely be due to chance. For a test to be effective at,
least three to four pens per diet are required.
3. Spread the pens on each diet throughout the barn
or room. This reduces biases due to pen location.
In almost all barns, there are pens that support better
performance than others.
4. Treat all pigs on the diets equally. Factors such
as feeder type, number ofpigs per pen, pen size and
shape, pen flooring material, waterer numbers, type
and location can all have an affect on performance.
Therefore, the impact ofsuch factors cannot be
allowed to bias the results of your experiment.
5. Be sure to compare diets at the same time.
Running one diet at one point in time and the
second diet at a later date could result in differences
in performance related to season or variable barn
environment.
6. The average initial weight should be the same
for all treatments. Heavier pigs will obviously grow
faster but convert feed less efficiently than smaller
pigs.
7. Sex is another important factor. ln starter trials,
sex can be ignored because there is little difference
between barrows and gilts at this age. As they grow
older though, differences in growth rate and carcass
quality emerge.
Ifthe comparison keeps these points in mind, any
differences observed in performance will likely be
due to diet. Random variation in the performance
of pigs does occur. Therefore, consistent differ-
ences between diets arc needed to draw meaningful
conclusions. For example, ifpigs on diet A grew an
average of I 0% faster than pigs on diet B, but three
out ofsix individual pens grew fastest on diet A and
three grew fastest on diet B, the overall I 0% differ-
ence in meaningless and no apparent difference in
the diets exists. If there was an overall difference of
10% though, and five out of the six individual pens
grew faster on diet A, then one can be reasonably
certain that it is a better diet (Table 5-6).
Ensure diets contain the same medication, espe-
cially when studying starter diets. Performance can
be greatly influenced by medication as well as by
make-up ofthe diet. To compare only the diets,
differences due to medication should be eliminated.
Again, the key to running a proper test is to elimi-
nate or at least minimize all sources of variabil ity
other than the factor being evaluated.
Select the pens and the pigs for the feeding trial.
Randomly assign pigs to the test pens assuring that
the average initial weight is constant and that litters
are spread out among pens. If the experiment ends
before the pigs reach 25 kg, do not separate them by
sex. If older pigs are being used, sex differences
start to show up and the number of barrows and
gilts in each pen should be the same. Record the
total weight ofpigs within each pen and randomly
allot diets to the test pens. Add a known amount of
feed to each feeder. As the experiment progresses,
continue to add feed as required, keeping records of
how much feed was added to each pen. At the end
of the experiment, weigh all of the pigs and record
the amount of feed left in each feeder. The
following calculations should be made to help draw
conclusions:
131

150. I. final weight ofpigs - starting weight of the pigs
= total pig gain
2. total pig gain + number ofpigs
= total gain per pig
3. total gain per pig+ number of days on test
= average daily gain
4. total feed added to feeder - feed left at end of
trial = total feed consumed
5. total feed consumed+ number ofpigs
= feed consumed per pig
6. feed consumed per pig+ number ofdays on test
= average daily feed
7. total feed consumed+ total gain
= feed conversion
8. feed cost per tonne+ 1000
= feed cost per kilogram
9. feed conversion x feed cost per kilogram
= feed cost per kilogram gain
Table 5-6. Examples of Conclusive (Experiment 1)
and Inconclusive (Experiment 2) Test Results, Based
on Average Daily Gain {g/pig/day).
If differences are small or results are in any way
questionable, repeat the experiment to strengthen
and provide confidence in the results. In all cases,
remember that bad information is worse than no
information at all. If the time, money and trouble is
to be invested in an on-farm test, efforts should be
made to carry it out properly.
Common Calculations and
Conversions
Converting 'dry matter' values to 'as fed':
Multiply the dry matter value by percent moisture.
Example 1: Convert dry matter to 'as fed'. A
sample ofbarley has 11.2% crude protein (CP) on a
dry matter (DM) basis and contains 10.5%
moisture. Express the percent protein on an as fed
basis.
Solution:
Ifthe barley contains I0.5% moisture, it contains 89.5%
(100-10.5 = 89.5%) dry matter. The amount ofprotein
on an as fed basis then, is 10.0% (11.2 x 0.895 = 10.0%).
Example 2:Convert 'as fed' to 'dry matter'. A
sample ofbarley has 11.0% protein on an as fed
basis and contains 10.0% moisture. Express the
percent protein on a dry matter basis.
Group
1
2
3
4
5
6
Average
Experiment J Experiment 2
Diet A Diet B Diet A Diet B
441 400 441 100
394 380 394 410
410 375 410 220
411 400 451 401
438 401 390 380
430 380 440 523
421 389 421 389
Solution:
Ifthe barley contains I0.0% moisture, it contains 90.0%
(100-10.5 = 90.0%) dry matter. The amount ofprotein
on a dry matter basis then is 12.2% (11.0 + 0.90 =
12.2%).
Additional Reading and References
Agricultural Research Council. 1981. The Nutrient
Requirements of Pigs. Commonwealth Agricultural
Bureaux, Farnham Royal. 307 pp.
Although the average performance on each diet is the
same in both experiments, Experiment 2 would not
support the conclusion that Diet A is better. Note that in
Experiment 2, Diet A outperformed Diet B only four out
ofsix times. In Experiment I, Diet A outperformed Diet
B six out ofsix times.
Australian Agricultural Council. 1987. Feeding
Standards for Australian Livestock: Pigs.
C.S.I.R.0., East Melbourne. 226 pp.
National Research Council. 1988. Nutrient Re-
quirements of Swine, 9th Ed. National Academy
Press, Washington. 93 pp.
132

151. 6. NUTRITION OF THE BREEDING HERD
Introduction
Adequate nutrition of the breeding herd is essen-
tial in order to maximize herd productivity and
profit. Ifone compares the reproductive efficiency
ofherds obtaining average productivity with those
obtaining higher levels ofperformance, consider-
able room for improvement is evident (Table 6-1 ).
Improvements in genetic quality and housing can
account for some ofthe variation in reproductive
efficiency observed. However, maximum reproduc-
tive efficiency can never be obtained unless the best
feeding and management practices are also fol-
lowed.
Table 6-1. Reproductive Efficiency ofAverage and
Superior Swine Herds.
Typical Superior
Baby Pig Mortality(%) 12 - 18 8
Weaning to Effective
Mating (Days) 8 - 10 5
Farrowing Rate(%) 78 - 85 90
Pigs Weaned/Litter 8.5-9.5 10.5
Litters/Year 2.0-2.3 2.4
Pigs Weaned/Sow/Year 17 - 22 25.2
to service interval, a reduction in conception rates
and a shortened reproductive lifespan. Therefore, it
is vital that the diet provided contains sufficient
quantities ofenergy, protein, essential fatty acids,
vitamins and minerals to allow the sow to perform
to its genetic potential.
Since nutrition is a primary factor influencing
reproductive efficiency, it follows that the
establishment ofa successful feeding strategy to
ensure optimum productivity must be based on a
sound knowledge of the response of the sow to
specified nutritional inputs. Traditional feeding
strategies often utilized the body reserves ofthe gilt
and sow to buffer short-term deficits in nutrient
intake with minimum effect on the fetus or suckling
piglets. However, modern sows, with a lean
genotype and superior reproductive performance,
must be managed differently from their counterparts
oftwenty years ago since they begin their
reproductive life with fewer body reserves.
Therefore, nutritional responses must be considered
more precisely and a strategy designed to conserve
body tissue must be employed.
Photo 6-1.
Before defining their desired feeding program,
pork producers need to establish goals for their
breeding herd. Typical questions that are relevant
include the genotype, the emphasis on sow
longevity, the type of housing employed (indoor
versus outdoor, group versus individual) and the
nature of the cun-ent sow herd including factors
such as appetite and body condition. Once such
questions are answered, the nature ofthe feeding
program can be more accurately defined.
Unfortunately, too many producers try to reduce
costs by cutting back on the quality of the diet fed.
This is a grave error as it is well documented that
feeding poor quality diets will adversely affect
reproductive performance. Failure to meet the
nutritional needs ofthe sow may result in smaller
Jitters, a reduction in piglet birth weight and vigor,
lower milk production, an increase in the weaning Some litters arejust too big for one sow to handle.
,/ 133

152. Feeding and Management of
Replacement Gilts
Survey data indicate that sow culling rates on
most commercial swine operations are somewhere
between 30 and 50%. As a consequence,
replacement gilts will constitute a significant
proportion ofthe breeding females in most swine
herds and any improvement in their productivity
will have a significant impact on the reproductive
performance of the entire herd. Factors influencing
gilt productivity include age at successful mating,
ovulation rate at the estrus ofmating, first litter size
and the ability to be successfully rebred. In far too
many herds, the gilt is a neglected member ofthe
breeding herd. However, by the adoption of an
appropriate replacement policy and proper gilt
management, the overall productivity ofany swine
enterprise can be markedly improved.
Feeding Replacement Gilts During the
Rearing Period
Gilts selected to enter the breeding herd will
typically have superior growth rates and lower
backfat levels than unselected pigs. As a
consequence. it is reasonable to expect their
nutritional requirements to be greater than those of
pigs destined for slaughter. In addition, diets
formulated to achieve cost-efficient, rapid growth
may not provide sufficient nutrients to prepare the
gilt for a long and productive breeding life.
Therefore, where possible, gilts destined to be used
in the breeding herd should not be fed the same
diets as those fed to market animals.
Nutrition during the rearing period (20-100 kg),
through its effects on body weight and backfat
levels, can influence the age at which puberty is
attained. Several studies have shown that restrict-
ing the feed intake ofyoung growing gilts (50-85%
ofad libitum intake) will delay the onset of puberty
by about IO to 14 days. To ensure that puberty is
not delayed, gilts should be fed ad libitum and
receive at least 35 MJ DE/day (8361 kcal/day)
between selection and mating.
Severe protein restriction or an amino acid
imbalance will also significantly delay the age at
which a gilt reaches puberty. Therefore, it is
important that producers not cut back on the use of
protein supplements during the developmental
period to ensure that puberty is not delayed.
However, diets formulated to meet the protein and
amino acid requirements ofslaughter animals will
typically provide more than enough protein to allow
gilts to express their potential in terms of
minimizing age at puberty. Therefore, producers
should not be unduely concerned about protein
restriction during this period. A diet formulated to
contain 15% crude protein (466 g/day)and 0.7%
lysine (217 g/day) should be adequate.
Diets formulated expecially for replacement gilts
should contain higher levels ofcalcium and
phosphorus compared with diets fed to feeder pigs.
The levels ofcalcium and phosphorus that result in
maximum growth rate are not necessarily adequate
for maximum bone mineralization. Feeding of
dietary levels ofcaJcium and phosphorus sufficient
to maximize bone mineralization in gilts during
early growth and development have been shown to
improve reproductive longevity in some studies.
Therefore, dietary calcium and phosphorus
requirements, expressed as a percentage ofthe diet,
are higher for gilts than for barrows and diets fed to
replacement gilts should be formulated to provide a
minimum of0.82% calcium (25.4 g/day) and 0.73%
phosphorus (22.6 g/day).
Genetic programs over the past 10-15 years have
placed considerable emphasis on selection for
leanness in gilts. The effects of these genetic
changes, combined with earlier mating, mean that
gilts now start their breeding lives with less body
reserves than in the past. This reduction in fat
reserves could adversely affect the long-term
reproductive performance ofgenetically improved
strains ofpigs. Australian workers have observed
that gilts which entered the breeding herd with
greater fat reserves were retained in the herd longer
and had a shorter average farrowing interval than
gilts with less fat reserves. It may therefore be
desireable to encourage potential replacement gilts
to deposit more body fat. Alteration of the lysine/
energy ratio could achieve this goal.
Puberty Induction
Age at successful mating is largely dependant on
the age at which the gilt reaches puberty. The mean
134

153. age at puberty for non-stimulated gilts is about 200
days of age, with a range of 135 to 250 days.
Canadian data indicate that fewer than I% ofgilts,
housed and managed under typical commercial
rearing conditions, will reach puberty by market
weight. Therefore, unless special steps are taken to
induce early puberty. most gilts will have a
prolonged interval between the age at which they
attain market weight and when they are able to be
successfully bred. The aim ofsuccessful
management should be to keep this unproductive
time to a minimum.
Although the normal pubertal age ofa gilt is
under genetic control, there are various factors that
have been shown to delay or advance the age at
which a gilt reaches puberty. Factors known to
influence the age ofpuberty include the breed of the
gilt, the housing conditions under which the gilt is
raised, the lighting regime and the degree ofstress
experienced by the gilt (mixing and relocation). As
a consequence, most producers could take steps to
reduce the average age ofpuberty in their herd.
The most potent stimulus for inducing early
puberty in gilts is boar exposure. Fence line contact
is not adequate as there must be direct physical
contact between the boar and the gilt. The best
response is obtained by taking the gilt to the boar
pen, not vice versa. This is likely due to the fact
that boar odors are stronger in the boar pen provid-
ing a greater degree ofstimulation for the gilt.
However, in order to stimulate puberty, the gilt must
be placed in the boar pen at least 20-30 minutes a
day, usually for a minimum of IO consecutive days.
Photo 6-2.
[la......
The most potent stimulus for inducing early puberty in
gills is boar exposure.
With proper stimulation, the mean age of puberty
in a herd can be 30 to 40 days earlier than for non-
induced gilts. Unfortunately, many producers who
have tried boar exposure have been unsuccessful in
inducing early puberty. The reason for their lack of
success is probably related to the fact that attain-
ment ofthreshold levels of age and weight arc
prerequisites for successful boar exposure. The
recommended minimum ages and weights for the
commencement of boar exposure are 140 days of
age and 70 kg body weight. With modern geno-
types ofswine, age is more likely to be a constraint
than is body weight and therefore it is unlikely that
gilts fed under commercial conditions will reach
puberty much before 90 kg.
It is important that ifearly puberty is induced,
gilts not be bred on their first heat as this practice
will result in a reduction in litter size. Research has
shown that an extra one or two pigs per litter can be
obtained by waiting until the second or third heat
before breeding replacement gilts. With induction
ofpuberty at 150 days ofage, gilts gaining weight
at a rate of 800 g/day should reach the desireablc
breeding weight of 115-125 kg by their third estrus
(192 days). Target backfat levels at mating are 17-
20 mm.
A major concern ofmany pork producers is that if
gilts are bred at too light a weight and with too little
backfat, the gilts will have a shortened reproductive
lifespan. However, recent research has shown that
this need not be the case. Lean gilts provide a
challenge to the producer, but if managed properly,
acceptable performance can be expected from gilts
induced to reach early puberty.
Feeding Replacement Gilts Prior to
Breeding
Ovulation rate is the principle factor limiting litter
size in gilts and there is a great deal ofexperimental
evidence showing that increasing the level of feed
intake during the rearing period will significantly
increase ovulation rate at puberty. lt is also well
established that short-term, high level feeding
(flushing) during the first estrus cycle increases
ovulation rate compared with gilts fed restricted
amounts offeed. Dutch researchers have suggested
that ovulation rate increases by about two ova in
135

154. Dyck et al., 1980, Can. J. Anim. Sci. 60: 877-884.
Adapted from den Hartog and van Kempen, 1980, Neth.
J. Agric. Sci. 28: 211-227.
Table 6.2. Influence Of Feeding Level Following
Mating On Embryo Survival in Gilts.
Table 6-3. Effect ofFeed Level in Early Gestation on
Plasma Progesterone Levels and Embryo Survival
13.8
10. I
73.2
12.3
9.7
78.3
Ovulation Rate
Number of Embryos
Embryo Survival (%)
Feed Level Embryo Survival Plasma
Progesterone
Concentration
(kg/day) (%) (ng/ml)
1.50 82.8 16.7
2.25 78.6 13.8
3.00 71.9 11.8
Low Energy High Energy
(22.9 MJ/day) (40.5 MJ/day)
The principle mechanism controlling the
development ofembryos and their subsequent
survival is the secretion ofuterine specific proteins.
These proteins are stimulated by ovarian steroid
hormones, particularly progesterone. A rise in
progesterone early in pregnancy enhances the
uterine environment and makes it more supportive
ofthe embyro. Increased gestation feed intakes
have been shown to be associated with a decrease in
plasma progesterone concentration as a result of
increased metabolic clearance ofprogesterone
leading to a subsequent reduction in embryo
survival (Table 6-3).
Recent data from the University ofAlberta
suggest that the first 72 hours after mating may be
ofcritical importance in determining the effect of
feeding level on embryo loss. Increasing feed
intake from 1.8 to 2.5 kg/day during the first 72
hours ofgestation significantly increased embryo
mortality whereas increasing feed intake after 72
hours did not increase embryo mortality. The
response to increased feed intake during the 14-day
period immediately prior to ovulation. As a conse-
quence, should feed intake be restricted for any
reason during the rearing period, special precautions
should be taken to ensure that gilts are ad lib fed (at
least 3 kg/day) for the two week period prior to
mating.
Flushing has been shown to increase plasma
levels of FSH and increase the pulse frequency of
LI-I suggesting that flushing enhances ovulation rate
by stimulating the secretion ofgondotrophins. The
increase in gonadotrophin secretion is thought to be
mediated through plasma levels of insulin and
insulin-like growth factor- I (lGF-1). The increase
in ovulation rate likely occurs either as result of
increased follicle recruitment or a reduction in
atresia.
Feeding Gilts Following Mating.
It has been determined that approximately 30% of
all potentially viable embryos die during the first 25
days ofgestation. High levels of feed intake
following mating have traditionally been associated
with an increase in embryo mortality. As a
consequence, it is usually recommended that feed
intake be restricted to approximately 2.3 kg/day
following mating. However, more recent evidence
suggests that the practise offeed restriction to
reduce embryo mortality may not necessarily result
in an increased litter size.
Most ofthe research which has shown an increase
in embryo mortality, as a result ofhigher feed
intakes early in gestation, has involved an increase
in feed intake at or very soon after mating. Such a
practise would increase ovulation rate and this
increase per se may lead to an increased embryo
mortality since higher ovulation rates are commonly
associated with higher embryo loss. The higher
ovulation rate followed by a higher embryo loss
produces a similar number ofembryos (and pre-
sumably piglets) to that obtained from gilts fed at a
lower level (Table 6-2).
136

155. Table 6.4. Effect of Energy Intake (day 75 to 105 of
Gestation) on Mammary Development in Gilts.
increased mortality in the first 72 hours was associ-
ated with a 10 hour delay in the normal rise in
plasma progesterone. As noted earlier, a rise in
progesterone, early in pregnancy, enhances the
uterine environment and makes it more supportive
of the embyro.
Clearly more research is needed on the effect of
feed intake in early gestation on gilt productivity.
However, given the current state ofour ignorance,
producers would be wise to continue the practise of
restricted feeding early in gestation, particularly
during the first 72 hours following mating.
during this period ofrapid mammary growth
impairs development ofthe mammary gland in gilts
and should be avoided.
Selecting very lean gilts for the breeding herd provides a
special chaJlenge to the producer. However, if managed
properly, lean gilts can become very productive members
of the breeding herd.
Summary of Replacement Gilt Feeding
Diets fed to potential replacement gilts should
contain 3100 kcal D.E./kg, I 5% crude protein,
0.7% lysine, 0.82% calcium and 0.73% phosphorus
and be fed ad libitum from the time ofselection
(50-60 kg) until needed for breeding. Gilts selected
for mating should have experienced at least two
heat cycles, weigh 115-125 kg and have 17-20 mm
ofbackfat. If feed intake is restricted for any
reason during the rearing period, special precautions
should be taken to ensure that gilts are ad lib fed (at
least 3 kg/day) for the two week period prior to
mating. For the first 72 hours following mating,
feed intake should be restricted to less than 2.5 kg/
day.
2.48
3.09
0.10
0.88
High Energy
( I 0.5 Meal/day)
l.12
3.22
4.07
.16
High feed intakes late in gestation may also be
detrimental to gilt productivity as they affect the
development ofthe mammary gland. In swine, total
mammary DNA can be used as an estimate of
mammary cell number and development. Minimal
development ofthe mammary gland occurs between
mating and day 50 ofgestation. The period of
maximal mammary development occurs between
day 70 and 105. During this time, a threefold
increase in mammary tissue occurs as measured by
total mammary DNA. Recent research at Michigan
State University has shown that a high level of
clietary energy during this critical period ofmam-
mary development reduced total marnmary
parenchymal DNA (Table 6.4).
Adequate Energy
(5.76 Meal/day)
Total DNA (mg)
Total RNA (mg)
Total Protein (g)
Wt ofParen-
chymal Tissue (g)
Weldon et al., 1991, J. Anim. Sci. 69: l94-200.
This reduction in DNA reflects a reduced mam-
mary cell number and may reduce the amount of
milk produced by the sow during lactation available
for nourishment of the offspring. Therefore, it
would appear that feeding a high level of energy
Feeding the Sow During Gestation
Introduction
The key to successful sow feeding is built around
the broad principle ofgenerous feeding during
lactation and strict rationing during gestation. There
is now general agreement that 1.8 to 2.7 kg offeed
137

156. per day (20 to 33 MJ/day) is satisfactory for preg-
nant sows housed under reasonable environmental
conditions when free ofheavy parasite infestation
and individually fed. Increasing the feed intake of
sows above this level would appear to be of little
benefit.
The effect of increasing feed intake during
gestation on subsequent litter size is shown in
Figure 6-1. It is evident that above a threshold
level, there is a wide range of feed intake over
which there is little effect on the number of piglets
born. At higher levels of intake the sow may
become overfat and litter size may decrease.
11
7
10 20 30 40 50
0.8 1.6 2.4 3.2 4.0
MJ DE/Day
KG Feed/Day
Figure 6-1. Effects of Feed Intake During Pregnancy
on Sow Productivity.
Increasing feed intake during gestation will also
dramatically increase sow weight gain but has very
little effect on the birth weight ofthe newborn pig.
Since these high levels ofintake are not improving
litter size or birth weight, considerable saving in
feed costs can be achieved by restricting the feed
intake ofsows in gestation.
A reduction in feed costs is not the only benefit
from restricting the feed intake ofsows during
gestation. There is some evidence that embryonic
survival and thus litter size may be increased by
restricting the level of intake during gestation. In
addition, farrowing difficulties may be reduced and
fewer piglets may be crushed by the sow.
Many producers believe that providing high levels
of feed during gestation will maintain the sow in
good body condition. However, research has shown
that as the level of feed intake during gestation
increases, the level offeed intake during lactation
decreases (see Table 6-23). Consequently, sows fed
high levels offeed during gestation will eat less
during their subsequent lactation and will start to
deplete their body reserves. Restricting feed intake
during gestation will prevent this loss ofbody
condition and may help to prolong the sow's repro-
ductive lifespan.
Methods of Restricting Feed Intake of Sows
During Gestation
Various management systems have been used
successfully to limit the energy intake ofsows
during gestation. These include:
-Hand feeding using gestation stalls
-Computer controlled feeding stations
-Slow feeding systems
-Self-closing individual stalls
-Skip a day feeding
-Selffeeding a high fibre ration
Gestation Stalls
Individual daily feeding, utilizing gestation stalls,
provides the greatest control over the feed intake of
the sow and is the method of choice for most
producers. Use ofgestation stalls provides the
greatest control over the feed intake ofthe sow as
each sow can be fed to condition resulting in a
reduction in feed costs. In addition, the elimination
offighting reduces prenatal losses.
Unfortunately, the increased cost ofgestation
stalls makes the system unattractive to many pro-
ducers and animal welfare groups have directed
criticism at them as well. Unless an automatic
feeding system is used, the gestation stall system is
very labor intensive. Furthermore. it has been
suggested that digestive upset (ulcers, twisted gut) is
worse in sows housed in gestation crates. There-
fore, alternative methods ofrestricting feed intake
have been sought by some producers.
Electronic Sow Feeders
The electronic sow feeder has recently been
introduced into Canada, following earlier experi-
ences in Europe. With this technique. 40 sows can
be fed using a single feeding station. The amount
138

157. Table 6-5. Comparison of Sows Fed with Electronic
Sow Feeders or in Gestation Stalls.
Use ofan electronic sow feeder does not appear
to have any detrimental effects on sow perform-
ance. In a British study. conception rate, litter size
and the incidence of farrowing problems were
similar for sows fed using an electronic feeder and
those housed under more traditional systems of
management (Table 6-5).
It must be pointed out that electronic sow feeders
are not completely fool-proof. Some sows have
learned that repeated banging ofthe feeding station
can dislodge a small amount offeed which will not
be accounted for on the computer printout. Regular
calibration is also necessary in order to correct for
differences in density between successive batches of
feed. In addition, collars and ear tags can be lost
thereby preventing a sow from feeding.
27
2.3
21.9
1.22
15.9
1.9
485
2.3
21.8
1.19
19.3
2.0
Gestation Electronic
Stalls Sow Feeders
MLC Pig Yearbook, 1989
Number ofHerds
Litters/Sow/Year
Pigs/Sow/Year
Feed/Sow/Year (tonnes)
Sow Replacements(%)
Sow Mortality(%)
Many producers have expressed concerns about
the possibility of sows fighting during mixing and
while queuing at the feed station. However, in most
cases, the large area available for avoidance and
escape has meant that aggression has not been a
problem and in fact, sows using the system are
extremely docile. Vulva biting has been one of the
more persistent problems, prompting modifications
in design. Ifother problems develop, it may be
because the feeder has been incorrectly located. rt
is important that the feeding station be sited to
allow free movement about the entry and exit
points. The feeder should be placed in an activity/
dunging area rather than a lying area as incorrect
siting results in sows lying at the station entrance
offeed that a sow gets each day is programmed into
the computer. When it enters the station, the trans-
ponder the sow carries causes small portions of feed
to be released. While the sow is eating, it is pro-
tected from other sows by a special crate which
ensures that they cannot steal her feed.
In essence, this system allows sows to be group
housed but individually fed. The systems most
attractive features are that it allows the use of
inexpensive, non-specialized buildings to house
sows during gestation and produces a daily report
on sow feed consumption. Electronic sow feeders
also find favor with animal welfare enthusiasts
because they are compatible with straw bedding and
allow the sow the chance to exercise.
Photo 6-3.
It does not appear difficult to train sows to use the
electronic feeder. One trial conducted in Britian
indicated that 50% ofsows required no training,
while a further 27% required only one assisted visit
to the feeding station in order to adapt to the
system. The majority ofsows seem to learn to use
the electronic feeding system within four days
although there may be a few sows which never
adapt and must be culled.
Sows housed outdoors require additional feed, especially
in cold, damp weather.��������������
Sows which are placed on the electronic feeder
establish a regular feeding cycle. The more
dominant sows eat first and the more timid sows
wait until later in the cycle. The computer system
allows the daily ration to be divided between a
number of feedings, but most sows consume all of
their daily allotment in one 12-15 minute feeding.
Ifa sow which has already had its full ration returns
to the station, no further feed is dispensed.
139

158. and blocking the access ofother sows to the feeder.
At this time, it is suggested that straw bedding and
not slatted floors be used in conjunction with
electronic feeding.
It is important to emphasize that electronic sow
feeders are not a replacement for good manage-
ment. Sow condition must still be monitored and
adjustments to daily allotment made. Depending on
the system employed, heat detection and repeat
breeders can become a serious problem.
Slow Feeding Systems (Biofix System)
Slow feeding systems are not presently available
in Canada but have been tested in the Netherlands.
Slow feeding systems dispense a continuous supply
of a small amount of feed at a predetermined rate.
The feed supply must be fast enough to prevent
sows from looking anywhere but their own troughs
for feed. On the other hand, the dispensing speed
must be slow enough that even the most reluctant
eater can keep up with the feed dispensed. In this
way, all animals in a group will finish eating at the
same time. This prevents the sows from fightng for
leftover feed. This so called biological fixation
makes it unnecessary to lock up the sows in the
feeding station. A simple 40-45 cm wide partition
between the troughs is sufficient to keep the sows
contrained (Figure 6.2).
In the systems tested, feed was supplied twice a
day from a volume dispenser and poured into a
container with a small mortar in the bottom. The
speed at which the mortar turns dictates the amount
of feed dispensed. The dosing speed has been
investigated in relation to leftover feed and aggres-
sive behavior (Table 6-6). The faster the feed is
dispensed, the less aggression develops and the less
likely it is that sows will move away from their own
troughs. Howver, the amount of leftover feed
increases. A dispensing speed of JOO to 120 g per
minute is recommended when pelleted feed is fed.
In general, the slow feeding system works well.
The advantages ofthe system are that the sows can
be checked during feeding and that they can learn
the system without any assistance. A disadvantage
is that the sows cannot be fed according to their
individual requirements.
Self-closing Individual Stalls (Woldrix System)
With self-closing individual stalls, it is possible to
have sows housed as a group and yet feed them
temporarily as individuals. The sow pen contains a
sufficient number offeeders to allow each sow to
eat individually as well as communal lying and
dunging areas. A slotted floor is situated at the
back ofthe pen and the sows have free access to all
ofthe feeding stalls at all times except during
PEN HOLDS SIX SOWS
[
GRID
SOLID
FLOOR
[ - HEATED - =GRID::::--
[ TROUGH=
Figure 6.2. Diagram of Slow Feeding System for Sows.
140

159. feeding (Figure 6.3). When feeding starts, the
entrance to each stall is locked automatically when
the sow pushes her head against the trough lid. The
stalls can also be locked manually by the stockman
as it is important that the entrance to each individual
pen be locked immediately after a sow enters to
prevent other sows from bullying them and driving
them away from the feeder. The feed required for
each feeding place is stored in a volume dispenser
and feed is poured into all the troughs at the same
time by the dispenser. Once all sows have con-
sumed their feed, the doors can be unlocked and the
sows are free to wander back to the dunging area.
self closing
1----1sHtal�
walking area
and c:::¢>
dunging area
� trough
� water
supply
Figure 6-3. Diagram ofWoldrix Feeding System for
Sows.
These systems have been tested in the Netherlands
since 1988. During and after feeding, there are very
few signs of aggression between sows. However,
reproductive data is not yet available to allow a
comparison ofthe system with more traditional
methods ofsow housing.
The Hurnick-Morris Housing System
This system was developed as a result ofa
cooperative study between the University of Guelph
and the Ridgetown College ofAgricultural
Technology. In the system tested, five pens are
located across the midsection of the barn (Figure
6.4). Each pen is 1 .6 x 6.6 meters in size and six
sows can be housed in each pen, providing
approximately 2 square meters per sow. Computer-
controlled entrance and exit gates are located at the
end of each pen. Two water drinkers are located
near the exit gates. Two boar pens with space for a
breeding area are located adjacent to the group sow
pens. Along the walls ofthe barn is a 1.2 m
alleyway for approaching and departing the feeding
compartments. The slatted areas extend along the
walkways and approximately 1.8 m into the pens at
the drinking/dunging end ofthe pens. The
remainder ofthe pen floor is solid and is suitable
for use with bedding.
Table 6-6. The Influence of Dispensing Speed on the Behaviour and Feed Intake of Sows Using the Slow
Feeding System.
Dispensing Speed (g/minute)
<80 81-100 101-120 121-140 141-160 161-180
Changes in Feeding Places 4.2 2.5 0.9 1.6 0.6 0.6
Aggressive Interactions 2.0 1.1 0.4 0.6 0.6 0.6
Feed Remainders
-none(%) 96 97 84 81 75 60
-a little(%) 3 2 13 15 14 15
-a lot(%) 3 4 11 25
Hoofs, 1990, Pig Production Trends for the l990's pp 14-23.
141

160. minutes. After this exercise period, the crowd gate
slowly advances, the sows return to their pen and
the entry gate closes. The sequence repeats for each
successive pen of pigs until all sows are fed. Dur-
ing the exercise period, each sow has the opportu-
nity to vist the boars at the front partition ofthe
boar pen. Interrogating antenna are also located on
the boar pens to recognize sows that are spending
time with the boar. Future development ofthis
aspect is to use the computer as a tool to assist the
manager in detecting sows in estrus.
cf
��BREEDING
cf :ta:
�<
"' • ...,w
t- <!!?
WALKWAY TO z
• :t (.)
(!)W za:FEEDING z�
• a:w
COMPARTMENTS -t- ��Oa:
:tl �I • t-o
wz
u.. �,
• a:<
�o, •"' o
OFFICE AREA
Figure 6.4. Diagram of Hnrnick-Mnrrls System for
Gestating Sows.
The feeding station consists ofsix individual
feeding compartments. Each compartment is fitted
with an interogating antenna near the feeding trough
which functions to identify individual sows. The
sows are fitted with passive transducers. Each
sow's identification is transferred to the system's
computer for proper proportioning and delivery of
feed. Sows are fed three times a day, but this can
vary depending on the objectives ofthe manager.
At feeding time, the computer activates and opens
the exit gate to the first pen of sows. and the sows
quickly move to the individual feeding compart-
ments. Once in the compartments, the exit gate
closes and the sows are identified by the computer
and fed according to their respective needs. Upon
completion offeeding, the sows are released
through the front gates of the feeders and the entry
gate to their pen opens.
Some sows will quickly return to their pen for a
drink while others will roam, investigate and social-
ize either in the pen or the alleyway for I 0-20
Preliminary data indicate that sows adjust to this
system relatively quickly. Reproductive perform-
ance has been at least equal to and in some cases
better than sows reared in conventional individual
gestation stalls.
Skip-a-day Feeding Programmes
A small proportion of swine producers do not
confine their breeding herd, but instead run their
sows outside in small groups. When sows are
housed in groups and the total feed given to the
group is reduced, boss sows will continue to eat to
appetite, leaving considerably less feed for the more
timid sows. This results in a large variation in the
body condition ofthe sow herd. Therefore, interval
feeding has been suggested as a method oflimit
feeding sows housed outdoors in groups.
With interval feeding, sows are permitted access
to a self feeder on a predetermined schedule. A
common procedure is to allow sows free access to
the self-feeder for eight hours during each ofthree
days of the week. Sows have access to water but no
feed during the remaining four days ofthe week.
During one eight hour period, a sow may consume
5-6 kg of feed, but ifthey only have access to the
feeder three days ofthe week, total weekly feed
consumption will only be I 5 to 18 kg. When
divided by seven days, this averages to 2. l or 2.6 kg
of feed on a daily basis. ffconsumption is too high,
the sow can be limited to less than eight hours
access to the feeder per day.
One major requirement ofthe skip-a-day system
is that adequate feeder space be provided. One
feeder space should be provided for each sow in the
group. ln addition, a careful eye should be kept on
142

161. the condition of the sows to ensure that they are not
being left for either too long or too short a time on
the self-feeder.
Sows adjust readily to this system and from all
research data, there appears to be no reduction in
reproductive performance as a result ofinterval
feeding. Most research indicates that sows fed on a
skip-a-day program farrow and wean a similar
number ofpiglets as sows fed every day. However,
no data on the success ofthis system is available for
herds weaning nine or more pigs per litter. For
intensive pork production, skip-a-day programs
would not be recommended due to a lack of control
over individual sows and also to concerns about the
welfare ofsuch systems.
Diet Dilution
A fourth method ofrestricting energy intake is to
dilute the diet with a high fibre ingredients so that
the sows may have constant access to the self-feeder.
Alfalfa hay, alfalfa meal, chopped straw or oat hulls
have been utilized. This system takes less labour
than the other methods of limit feeding but is the
least acceptable because it costs more to maintain the
sow and it is difficult to prevent sows from getting
fat, even though the energy content ofthe feed is
lower. In addition. there are problems associated
with grinding high fibre feeds and such feeds tend to
bridge in the self-feeder. Therefore, the use ofhigh
fibre feeds to limit the energy intake ofsows during
gestation is not recommended.
Factors Affecting the Required Feeding
Level During Gestation
Although there are many advantages to restricting
intake during gestation, it must be emphasized that
the actual feeding level will vary according to
individual situations and animals. Factors that
should be considered when determining individual
feeding levels include the:
- size ofthe gilt or sow
- condition of the sow
- method ofhousing
- environment provided
- method of feeding
- health of the herd
- productivity level
- standard ofmanagement.
The size ofthe sow or gilt is going Lo affect the
level of feed required. The heavier the sow, the
greater the maintenance requirement and the greater
the amount offeed required. Energy requirements
increase by about 5% for each IO kg increase in
body weight. The condition ofthe sow is another
factor determining the feeding level required during
gestation. A thin sow will have less thermal
insulation than will a fat sow. Therefore, it will be
less able to adjust to lower environmental
temperatures. As a consequence, a thin sow will
require a larger increase in feed at a lower
temperature than will a sow in good condition.
The environment in which the sow is housed
should also be taken into consideration when feed
allowances are being set. Sows housed at lower
environmental temperatures require more feed than
sows housed in their comfort zone. The energy in
the excess feed is used to produce heat to enable the
sow to maintain a constant body temperature. For
individually housed sows, the lower critical
temperature (temperature below which feed must be
used to produce heat) is about 16-l 8°C. lfthe
environmental temperature drops below this level,
feed intake should be increased by 3-4% for every
I°C below the lower critical temperature. Sows
housed in wet or drafty conditions wilJ also require
increased feed.
Sows which are housed and fed in groups com-
pete with each other for the available feed. There
may be considerable inequality in the feed intake of
individual sows. Therefore, sows which are fed in
groups should be given feed allowances which are
about 15% above that of sows fed individually.
This will ensure that those sows which are domi-
nated by others receive feed intakes that are suffi-
cient to prevent reproductive failure.
The health ofthe herd is also going to affect the
feeding level required during gestation. The effect
ofa disease burden is difficult to quantify in nutri-
tional terms, but represents an important influence
on the utilization offeed. For example, sows
infected with worms may actually lose weight
through gestation and produce smaller litters. This
emphasizes the importance of monitoring for
worms and deworming when necessary.
143

162. Feeding Pattern Throughout Pregnancy
It is often suggested that the nutrient requirements
ofpregnant sows are higher in early pregnancy
when the embryos are being implanted and during
the last third ofpregnancy when the fetuses are
growing very rapidly. As logical as this may appear
in theory, several large scale experiments have
shown that the performance of sows fed a constant
level of feed throughout pregnancy is as good as
that achieved by increasing feed intake in early or
late gestation (Table 6-7). Since a constant level of
feeding does not impair reproductive efficiency, its
simplicity should make it the method ofchoice.
Table 6-7. Effect of Feeding Level During Last 23
Days of Gestation on Reproductive Performance.
Piglets ( 11 at 1.3 kg)
Membranes
Uterine Fluids
Uterus
Udder
Sow
13.9 kg
2.5 kg
2.0 kg
3.2 kg
3.4 kg
20.0 kg
45.0 kg
Table 6-8. Components of Gestational Weight Gain.
weight during pregnancy will enter lactation with
low body stores of fat which will adversely affect
the ensuing lactation and increase the interval
between weaning and successful mating. An
example of the components ofgestation weight gain
is given in Table 6-8.
Feed Intake (kg/day)
1.8 3.2
Pigs Born Alive 9.9 10.1
Birth Weight (kg) 1.4 1.4
Pigs Weaned (day 21) 8.3 8.5
Weaning Weight (kg) 5.3 5.4
Survival Rate(%) 84.8 84.7
Returns to Estrus (days) 5.7 5.7
Cromwell et al., 1989, J. Anim. Sci. 67: 3-14.
A cooperative research study involving 8 research
stations and I 080 Litters.
Evaluating Your Feeding Program During
Gestation
Since there are so many factors affecting the level
offeed to be fed during gestation, producers are
advised to evaluate their feeding program to ensure
that satisfactory levels of intake are being main-
tained. Two methods are available, one is to weigh
sows to ensure adequate but not excessive weight
gain and the second is to employ condition scoring.
The former is labour intensive, but objective. The
second requires less labour, but is subjective and
therefore must be managed well to be successfuJ.
The gilt or sow should gain weight during preg-
nancy to compensate for the weight of the litter and
fetal membranes as well as to allow for a normal
increase in sow body weight. Animals losing
Up to about the fifth litter, sows should gain ap-
proximately a total of 45 - 50 kg during gestation.
This allows for 20 - 25 kg net weight gain by the sow
and 25 kg for fetal tissues. After the fifth litter, a 25
kg total gain (0 kg net weight gain) during gestation is
sufficient. Sows which are gaining just over 0.4 kg
per day (0.2 after 5th parity) will obtain the desired
weight gain during the gestation period.
Condition scoring uses a combination ofvisual as-
sessment ofthe sow's general appearance and an esti-
mation of its body fat reserves to arrive at a number
or score. The chart in Fiqure 6-5 provides illustra-
tions as well as descriptions of the five body condi-
tion classifications into which sows are grouped.
Body fat is estimated by applying firm finger pres-
sure over the top-rear (H-bones) of the pelvic girdle
(Figure 6-5). The amount offat isjudged by estimat-
ing the degree of difficulty involved in locating and
palpating these structures. It should take no longer
than three seconds to feel the H-bones with the fin-
gertips. If it takes longer than this, the sow should be
rated either a four or a five.
The first step in assessing the adequacy ofyour
feeding program is to obtain an average score for
the dry sows in the entire herd. Ifthe average is less
than three, then the daily feeding allowance should
be increased. Ifthe average score is greater than
three, a decrease is necessary. Table 6-9 indicates
how much feed allowances should be altered based
on the average condition score ofthe herd.
144

163. Condition Score
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
Change in Feed
(kg)
+ 0.60
+ 0.40
+ 0.30
+ 0.20
0.00
- 0.20
- 0.30
- 0.40
- 0.60
Energy
For the gestating sow, energy is required for
maintenance, growth ofmaternal tissue and growth
ofthe fetus. The maintenance energy requirement
is dependant on the size of the sow and has been
estimated to be approximately 110 kcal DE/kg 75
per
day and represents in excess of 75% of a sow's
daily energy requirement. To calculate maintenance
energy requirements, one must know the weight of
the sow at breeding and the expected weight gain
during gestation in order to calculate the average
weight ofthe sow during gestation. The traditional
thumb rule has been to target for 20-25 kg of
maternal weight gain and 20 kg of reproductive
tissue per parity at least up until the 5th parity when
mature body size is achieved. Table 6-10 converts
actual body weight (BW) to metabolic body weight
(BW 75
) A calculator that has a yx key can also be
used.
Froese, 1987, Manitoba Agriculture Swine Fact Agdex
No. 440-22-40.
Table 6-9. Feed Allowances For Dry Sows According
To Body Condition Score.
Nutrients Required During Gestation
Based on the foregoing discussion, it can be
concluded that the provision ofa high quality diet is
essential for sows during gestation. Such a diet is
necessary in order to provide adequate levels of
nutrients to allow for fetal growth, growth ofthe
uterus and mammary glands and body growth as
well as replenishment ofthe sow's body reserves
depleted during the previous lactation. Therefore,
producers are encouraged to conduct a feed analysis
to confirm that the diet being fed meets the gestat-
ing sow's requirements.
The energy requirement for maternal growth is set
by the desired body weight gain during gestation.
The energy cost per kg ofmaternal gain is
approximately 5 Meal ofDE/kg. Therefore, the
energy cost/day for a sow with a net weight gain of
25 kg in a 114 gestation period is 1.10 Meal ofDE
(125 Meal+ 114 days). The daily energy
requirement for the growth ofthe conceptus has
been estimated at 0.19 Meal ofDE resulting in a
total energy cost/day of 1.29 Meal ofDE.
Table 6-10. Metabolic Body Weights of Sows and Maintenance Energy Requirements.
Parity Body Weight Body Weight Average Body Metabolic Body Maintenance Energy
at Start (kg) at Finish (kg) Weight(kg) Weight (kg·75
) Required (Meal/day)
Gilt 120 165 142.5 41.2 4.53
I 145 190 167.5 46.6 5.12
2 170 215 192.5 51.6 5.68
3 195 240 217.5 56.6 6.23
4 220 265 242.5 61.4 6.76
5 245 290 267.5 66. l 7.27
6+up 270 290 280 68.4 7.52
145

164. - -
I. POOR - Hips and backbone are prominant
2. MODERATE - Hips and backbone are easily felt without applying palm pressure
3. GOOD - Hips and backbone can only be felt with firm palm pressure
4. VERY GOOD - Hips and backbone cannot be felt
5. FAT - Hips and backbone arc heavily covered
Figure 6-5. Guides to Condition Scoring Sows, Including Photographs of Representative Animals.
146

165. Table 6-11. Energy Requirements of Sows (Estimated) During Gestation.
Average Gestation Body Weight'
142.5 kg 217.5 kg 270 kg
Energy Required (Meal/day)
Maintenance!
Gestation Weight Gain3
Total
Feed Required/day (kg)"
4.53
1.29
5.82
1.84
6.23
1.29
7.52
2.38
7.32
0.19
7.51
2.38
I Assumes breeding weights of 120, 195 and 260 kg with maternal weight gains of45, 45 and 20 kg.
2Thc sows daily maintenance requirement is 110 kcal ofDE/kg BW75
3The requirement for gestation weight gain is 1.10 Meal ofDE/day for maternal tissue plus 0.19 of DE/kg for
eonceptus gain.
"Assuming diet contains 3, 150 kcal DE/kg. Allowance should be increased by 300 to 400 kcal for every 5°C below
critical temperature ( I 6°C).
Table 6-11 demonstrates how to calculate the
daily energy requirements under three different
conditions. The first column calculates the energy
requirements for a gilt bred at 120 kg and gaining
45 kg during gestation. The 2nd column shows the
calculation for a 4th parity sow being bred at 195
kg and gaining 45 kg during gestation while the
lastcolumn shows a mature sow bred at 270 kg and
gaining only 20 kg (reproductive tissue only) during
gestation. However, using the values above, pro-
ducers can calculate daily energy requirements for
any sow under any conditions. Dividing these
energy levels by the energy content ofthe feed will
provide an estimate ofthe daily feed intake required
to provide this level of energy (i.e., 5.82 Meal+ 3.2
Meal/kg diet= 1.8 kg feed/day).
Amino Acids
Amino acids are needed during pregnancy to
replace those lost through obligatory sloughing or
metabolism, to develop the pregnant uterus and its
contents, to develop the mammary gland as well as
to add protein to the maternal body. The amounts
ofthe indispensable amino acids needed during
pregnancy can be estimated by summing the
amounts needed for maintenance and for maternal
protein accretion.
During gestation. there is a continous sloughing of
cells from tissues such as the skin and intestinal
mucosa. These represent obligatory losses ofamino
acids from the body and this loss must be replaced
in order to maintain constant conditions. This is
called the maintenance requirement and this loss has
been estimated in a number ofexperiments which
have been averaged to produce the numbers in
Table 6-12.
The amino acid requirements for growth of
maternal tissue can be calculated from the amino
acid content ofpork. The best available estimates
ofthe protein content ofpork suggest a value of
15.3%. Therefore. a sow gaining 45 kg (25 kg
maternal and 20 kg reproductive tissue) during a
115 day gestation will be depositing 59.86 g of
protein per day (6885 g/115 days). By multiplying
this value by the amino acid content of lean tissue,
one can calculate the required level ofa specific
amino acid needed on a daily basis. It has been
estimated that amino acids used for growth and the
products ofconception are used at an efficiency of
63.5% and we can assume that the gestation diet is
about 80% digestible. Under these circumstances,
the value derived from multiplying the amount of
protein deposited daily by the sow by the amino
acid content of lean tissue must be divided by a
factor of .508 (63.5% efficiency x 80% digestion)
to arrive at the daily amino acid pattern required for
growth and reproductive tissue. A mature sow (ie
one no longer gaining maternal tissue) will only
gain 20 kg during gestation and therefore the daily
protein deposition will be only 26.6 g/day (3060 gl
115 days). For example calculations of the daily
amino acid requirements sec Table 6-13.
147

166. Table 6-12. Daily Amino Acid Requirements for Maintenance of Gestating Sows (g/day).
Sow Weight at Mating (kg)
Sow Weight at farrowing (kg)
Average Metabolic Weight (kg·1s)
120
165
41.24
195
240
56.63
260
280
68.44
Amino Acids
Required for
Maintenance (mg/kg75
)
1
Arginine O
Histidine O
Isoleucine 30
Leucine 20
Lysine 25
Total Sulfur Amino Acids 26
Total Aromatic Amino Acids 46
Threonine 39
Tryptophan 5
Valine 21
Amino Acid Required (g/day)
1.23 1.69 2.05
0.82 1.13 1.37
1.03 1.41 1.71
1.07 1.47 1.78
1.89 2.60 3.14
1.61 2.20 2.66
0.21 0.28 0.34
0.87 1.19 1.43
'Based on Baker et al ( 1966; J. Nutr. 88: 382-396) and Baker and Allee (1970; J. Nutr, 100: 277-280).
Table 6-13. Daily Amino Acid Reqirements {g/day) for Growth of Gestating Sows (Growth and Products of
Conception).
Amino Acid Content Estimated Gestation Gain ofSow
of Lean Tissue (%)2
20 kg (26.6 g/day) 45 kg (59.86 g/day)1
Arginine 6.71
Histidine 4.29 2.24 5.03
Isoleucine 4.32 2.26 5.07
Leucine 7.38 3.85 8.68
Lysine 7.90 4.13 9.29
Total Sulfur 3.32 1.73 3.89
Total Aromatic 7.48 3.91 9.17
Threonine 4.16 2.16 4.90
Tryptophan 1.01 0.51 1.18
Valine 5.10 2.65 6.00
'Numbers in brackets indicate daily protein deposition (g)
2
Adapted from Speer ( 1990; J. Anim. Sci. 68: 553-56 I)
148

167. To calculate the total daily amino acid
requirements ofsows in gestation, one must sum the
maintenance requirement and the requirement for
growth. Table 6-14 demonstrates how to calculate
the daily amino acid requirements under three
different conditions. The first column calculates
the amino acid requirements for a gilt bred at 120
kg and gaining 45 kg during gestation. The 2nd
column shows the calculation for a 4th parity sow
being bred at 195 kg and gaining 45 kg during
gestation while the last column shows a mature sow
bred at 270 kg and gaining only 20 kg (reproductive
tissue only) during gestation. However, using the
values shown above, producers can caJculate daily
amino acid requirements for any sow under any
conditions.
The above example likely provides more detail
than would be required by the average producer and
it would be virtually impossible to provide a diet
that provides precisely the amino acid balance
shown in Table 6-14. However, since lysine is the
first limiting amino acid, under these conditions, it
is the amino acid we should be most concerned with
in diet formulation. Using the estimated daily
lysine requirements shown in Table 6-14 and
dividing by expected daily feed intakes in Table 6-
11, one arrives at the percentage of lysine required
in the diet to meet requirements (i.e. 0.56%, 0.45%
and 0.24% for the 120, 195 and 270 kg sow,
respectively, compared with 0.43% for NRC).
Table 6-14. Estimated Total Amino Acid Needs of Pregnant Sows Under Various Conditions (g/day).
Weight at Mating (kg) 120 195 260 Current
Weight Gain During Pregnancy (kg) 45 45 20 NRC
Amount of Amino Acid Required (g/day)
Arginine
Histidine 5.03 5.03 2.24 2.8
Isoleucine 6.30 6.76 4.31 5.7
Leucine 9.50 9.81 5.22 5.7
Lysine 10.32 10.70 5.84 8.2
Total Sulfur Amino Acids 4.96 5.36 3.51 4.4
Total Aromatic Amino Acids 11.06 11.77 7.05 8.6
Threonine 6.51 7.10 4.82 5.7
Tryptophan 1.39 1.46 0.85 1.7
Valine 6.87 7.19 3.48 6.1
1NRC values are based on a sow with an average gestation weight of 162.5 kg consuming 1.9 kg/day of a diet con-
taining 12% crude protein.
Some flexibility can be obtained by varying the
level offeed intake to meet the lysine requirements
of sows of different weights. However, larger
producers might find it cost effective to formulate at
least two diets varying in lysine content and feed
one to sows less than five parities and one to sows
over five parities.
Minerals
The most commonly used estimates of mineral
requirements ofgestating sows are those ofthe
NRC (1988) and the Australian Standing
Committee on Agriculture (1987). Reasonable
agreement exists between these two groups in
setting nutritional standards. Where differences
exist, it is suggested that the Australian Standards
be used because these standards tend to be based on
ingredisimilar to those most commonly used in
Canada and the predominant breeds in the two
countries (Large White and Landrace) are also
similar. Current recommendations are shown in
Table 6-15.
149

168. Table 6-15. Mineral Requirements of Gestating Sows
(% or amount/kg of total diet).
Table 6-16. Vitamin Requirements of Gestating Sows
(Total Supplied in Diet).
NRC1
Australia2
Calcium(%) 0.75 0.82
Phosphorus(%) 0.60 0.73
Sodium(%) 0.15 0.12
Chloride(%) 0.12 0.14
Magnesium(%) 0.04 0.04
Potassium(%) 0.20 0.23
Copper (mg) 5.00 4.00
Iodine (mg) 0.14 0.40
Iron (mg) 80.0 60.0
Manganese (mg) 10.0 10.0
Selenium (mg) 0.15 0.15
Zi11c (mg) 50.0 45.0
'National Research Council, 1989. Nutrient Require-
ments of Swine.
2
Standing Committee on Agriculture, I 987. Feeding
Standards for Australian Livestock: Pigs.
Vitamin A (IU)
Vitamin D (IU)
Vitamin E (IU)
Vitamin K (mg)
Biotin (mg)
Choline (g)
Folic Acid (mg)
Niacin (mg)
Pantothenic Acid (mg)
Riboflavin (mg)
Thiamin (mg)
Vitamin B6
(mg)
Vitamin B12
(ug)
NRC1
4,000
200
22
0.50
0.20
1.25
0.30
10.00
12.00
3.75
1.00
I.00
15.00
Australia2
2,100
200
10.5
0.27
0.10
1.50
0.60
10.00
12.00
2.70
1.40
1.40
15.0
1
National Research Council, 1989. Nutrient Require-
ments ofSwine
2
Standing Committee on Agriculture, 1987. Feeding
Standards for Australian Livestock: Pigs.
Vitamins
Vitamins have long been recognized as having an
essential role to play in reproduction and a consid-
erable amount ofresearch has been devoted towards
determining the vitamin requirements ofthe gestat-
ing sow. Current recommendations are shown in
Table 6-16.
Feeding recommendations must continually be
modified as more research is conducted and we
learn more about the nutrient requirements of
animals. 1n the past few years, new evidence has
come to light which suggests that current recom-
mendations are inadequate for several vitamins and
it is likely that the next set of requirement tables
will show a recommendation for higher levels of
supplementation for these vitamins. These changes
will likely affect folic acid beta-carotene and
vitamin E.
Folic acid has received considerable attention in
the past few years with several experiments show-
ing a response to supplementation at levels greatly
in excess ofthose currently recommended. The
most common finding has been an increase in litter
size (Table 6.17). As a consequence, folic acid
levels of approximately I mg/kg or about three
times current NRC ( 1988) levels are recommended.
Table 6-17. Effects of Felic Acid Supplementation of
Diets Fed to Gestating Sows.
Control FolicAcid
( 1.00 mg/kg)
Pigs Born Alive 9.51 10.64
Birth Weight (kg) 1.48 1.48
Pigs Weaned (day 29) 8.92 9.24
Weaning Weight (kg) 7.68 7.44
Weaning to Estrus
Interval (days) 7.30 6.66
Lindemann and Kornegay, I 989, J. Anim. Sci. 67: 459-
464.
150

169. The increase in litter size as a result offolic acid
supplementation has been attributed to a decrease in
embryo mortality. The rate of cell proliferation
during embryonic development is extremely high
and the intracellular concentration ofRNA, a key
component, is highly correlated with embryo
survival. The synthesis of the nucleic acids DNA
and RNA requires purines and pyrimidine bases, the
production ofwhich in tum requires single carbon
units. As folic acid is an indispensable cofactor in
the metabolic transfer ofsingle carbon units, it is
logical to assume that an adequate supply is essen-
tial for minimizing embryo losses.
Another area ofrecent research interest has been
in the use ofbeta-carotene injections around the
time ofmating. Beta-carotene is a natural precursor
ofvitamin A, but recent evidence suggests that it
may have a unique role in reproduction independant
of its function as a precursor of vitamin A. The
most common finding with beta-carotene injection
is a modest improvement in litter size (Table 6-18).
The increase in litter size is suggested to result from
a decrease in embryo mortality. Dietary supple-
mentation (as opposed to injections) is unlikely to
result in an increased litter size because beta-
carotene is not absorbed intact from the digestive
tract ofswine.
proteins with immunosupprcssive capabilities have
been identified. These proteins play a key role in
embryo development and could explain the
increased litter size observed with beta-carotene
injection. Beta-carotene may also increase the
production ofprogesterone during the initial
formation ofthe corpora lutea. which would
provide a more favorable environment for embryo
survival. Unfortunately, injectable beta-carotene is
not currently cleared for use in Canada.
Vitamin E has also received considerable research
attention and again there are suggestions that current
recommendations (22 JU/kg) may not be adequate
for high producing sows. A recent Ohio study
examined supplementation with 16, 33 or 66 JU
vitamin E for three parities and observed increased
litter size at birth and weaning as the vitamin E level
increased (Table 6.19). The data suggest that sows
housed in less sanitary conditions respond more
positively to higher vitamin E levels with reduced
incidence ofmastiris than those housed in clean
facilities.
Table 6-19. Effect ofVitamin Eon Sow Productivity.
Supplemental Vitamin E (fU/kg)
Days to Estrus
Farrowing Rate(%)
Pigs Born Alive
Birth Weight (kg)
Control
4.6
88.7
10.0
1.5
Beta-carotene1
4.5
88.4
10.6
1.5
0 16 33 66
Pigs Born Alive 9.85 10.87 11.20 10.04
Birth Weight (kg) 1.39 1.31 1.37 1.41
Pigs Weaned (28 days) 6.73 7.00 7.88 8.14
Weaning Weight (kg) 6.51 6.27 6.21 6.49
Piglet Survival(%) 68.30 64.30 70.30 81.00
'Basal diet contained 8.4 mg/kg vitamin E. Experiment
conducted over 3 parities.
2Mahan, J 991, J. Anim. Sci. 69: 2904-2917.
Feeding the Sow Around Farrowing
Time
Feeding Levels
Opinions as to the level of feed to be provided
immediately prior to and for the first few days after
farrowing arc divided. Excessive restriction can
cause excessive sow excitement due to hunger
resulting in an increase in piglet deaths due to
151
Table 6-18. Effect of Injection of Beta-Carotene on
Reproductive Performance of Multiparous Sows.
'Sows were given i.m. injection of200 mg of Beta-
carotene on the day of weaning, breeding and day 7 of
gestation.
2Coffey and Britt, 1993, J. Anim. Sci. 71: 1198-1202.
The mechanism by which beta-carotene enhances
embryo survival is not certain. However, it has
been shown that beta-carotene can increase the
production of uterine specific proteins which
support embryo survival. A basic glycoprotein with
iron binding capacity and a groups ofacidic

170. crushing. There is also concern about feeding too
much. Therefore, a balance has to be kept in
relation to the feeding level around farrowing.
Before the sow farrows, it is probably best to
maintain the same level of feed intake as that
normally fed during gestation (2 - 2.5 kg). Follow-
ing farrowing, a gradual increase in feed intake is
recommended, with the objective ofgetting the sow
to maximize feed intake as soon as possible into her
lactation.
Use of Laxatives Prior to Farrowing
Many producers add wheat bran, beet pulp or
some other bulky feed to the sow's diet before and
for a few days after farrowing. It is a believed that
this practice helps prevent constipation, reduces the
incidence of mastitis and may prevent death loss
due to twisted gut. The most recent research on this
subject does not support the need for the addition of
such bulky feeds as a means ofpreventing mastitis
or improving sow productivity. However, the
addition ofbulking agents may improve sow
comfort and produce a softer stool. Ifsows are
experiencing problems with constipation, producers
may wish to consider the addition of 5 to 15% bran
or 5 to 7% beet pulp to the prefarrowing diet.
Potassium chloride or potassium magnesium sulfate
have been used as laxative agents at the rate of0.5
to 1.5% of the total diet. However, the longterm
effect of such salts on the health ofthe sow are
unknown.
Feeding Fat in Late Gestation and Lactation
A topic ofrecent research interest has been the
addition offat to sow diets during late gestation and
lactation in an attempt to improve the survival of
baby pigs. Baby pig losses are often high during
lactation, with the greatest losses attributed to
crushing by the sow. Pigs which are crushed are
often hypoglycemic due to low glycogen stores.
These low energy stores result in weak piglets
which may be unable to move out of the way ofthe
sow and are subsequently crushed.
It has been hypothesized that the incorporation of
fat into diets fed during late gestation and lactation
will increase both milk yield and milk fat content,
thus increasing the energy supply available to the
nursing pig. This increase in available energy may
result in a reduction in preweaning mortality.
Furthermore, the increased energy level in the sow
diet may decrease sow weight loss during lactation.
The response to fat inclusion is variable and a
beneficial response has not been reported in all
cases. The amount of fat fed prior to farrowing
affects the response obtained. ln general, the
greater the amount offat fed, the greater the re-
sponse. It appears that sows must be fed at least
one kg of fat prior to farrowing in order to obtain
any benefit. Therefore, it is usually necessary for
fat to be included in the diet at a level ofat least
10%. In addition, fat must be fed for at least five
days prior to farrowing to obtain a positive re-
sponse. This time period is required in order to
allow the sow time to make the physiological
adjustments necessary to absorb the fat and trans-
port it to the mammary glands.
Unfortunately, the inclusion ofa high level offat
in the diet is relatively expensive and may result in a
very greasy feed. The potential to obtain an eco-
nomical response is greatest when mortality is high
and birth weights are low. Most producers will find
it uneconomical to routinely include fat in their sow
diets unless preweaning mortality is greater than
25% or the incidence of low birth weight piglets is
inordinately high. However, producers should not
underestimate the benefits ofhigh fat feeding when
environmental temperatures rise above 25°C.
Under these circumstances, high levels ofdietary fat
are beneficial in maintaining energy intakes of
lactating sows, increasing sow milk production and
thereby increasing survival and weaning weights of
piglets.
Most of the early work on fat supplementation of
sow diets involved the use offats made up pre-
dominantly of long chain (>Cl6:0) fatty acids (i.e.
tallow or soybean oil). An area ofrecent research
interest has involved the study offats made up
predominately of medium or shorter chain fatty
acids (<C: 12:0). Coconut oil is one readily avai1-
able source of medium chain fatty acids. These
shorter chain fatty acids are known to more easily
digested by swine and have found use as energy
sources in creep and starter diets. However, it is
only recently that they have been studied as an
152

171. Table 6-20a. Examples of Gestation Diets
Ingredients, % 2 3 4 5 6
Barley 86.0 87.2 78.8
Corn 82.0 72.5 48.5
Peas 10.0
Wheat shorts 40.0
Soybeanineal-47°/o 4.5 7.8 13.0 6.5
Canola rneal 4.5 22.5 6.2
Premix 5.0 5.0 5.0 5.0 5.0 5.0
Nutrients, minimum %
D.E., kcal/kg 3,000 3,000 3,390 3,300 3,000 3,250
Crude protein l3.0 13.0 13.1 14.8 13.1 14.3
Digestible lysine 0.43 0.43 0.49 0.48 0.43 0.46
Digestible methionine 0.16 0.16 0.18 0.18 0.16 0.17
Digestible TS.A.A. 0.20 0.20 0.23 0.22 0.22 0.22
Digestible threonine 0.27 0.27 0.31 0.30 0.27 0.29
Digestible tryptophan 0.06 0.06 0.07 0.07 0.06 0.07
Calcium 0.85 0.85 0.85 0.85 0.85 0.85
Phosphorus 0.75 0.75 0.75 0.75 0.75 0.75
Sodium 0.15 0.15 0.15 0.15 0.15 0.15
Chloride 0.15 0.15 0.15 0.15 0.15 0.15
Table 6-20b. Examples of Lactation Diets
Ingredients, % l 2 3 4 5 6
Wheat 50.00 50.00 49.67
Barley 26.30 21.90 25.20
Com 76.00 71.70 70.65
Soybean meal - 47% I 1.70 19.50 15.80 23.30 15.10 24.20
Canolameal 7.50 7.50 3.20
Fat/oil 1.00 1.00 1.30 1.00 2.50 l.00
LysineHCI 0.23 0.10
Threonine 0.10 0.05
Premix 3.50 3.50 3.50 3.50 4.00 4.00
Nutrients, minimum %
D.E.. kcal/kg 3,250 3,460 3,300 3,415 3,350 3,460
Crude protein 18.6 15.6 19.3 17.2 18.0 17.5
Dig. lysine 0.65 0.65 0.75 0.75 0.85 0.85
Dig. methionine 0.16 0.16 0.19 0.19 0.21 0.21
Dig. T.S.A.A. 0.33 0.33 0.38 0.38 0.43 0.43
Dig. threonine 0.41 0.41 0.47 0.47 0.54 0.54
Dig. Tryptophan 0.10 0.10 0.11 0.11 0.13 0.13
Calcium 0.85 0.85 0.85 0.85 0.85 0.85
Phosphorus 0.75 0.75 0.75 0.75 0.75 0.75
Sodium 0.15 0.15 0.15 0.15 0.15 0.15
Chloride 0.15 0.15 0.15 0.15 0.15 0.15
These are sample diets only and are for illustrative purposes only. While every attempt has been made to present
examples that reflect successful commercial formulations, these examples arc not intended for actual use without
assistance from a qualified nutritionist.
All amino acid concentrations are expressed as apparent ileal digestible amino acids.
153

172. ingredient in sow diets. The results ofa recent
study conducted at the University of Georgia are
shown in Table 6-21.
Table 6-21. Effect of Type of Fat Fed During Late
Gestation and Early Lactation on Sow Productivity.
Control Long Medium
Chain Triglycerides
Pigs Born Alive 11.33 10.79 11.59
Birth Weight (kg) l.27 1.31 1.21
Pigs Weaned (day 21) 9.06 8.89 10.12
Weaning Weight (kg) 5.48 5.62 5.51
Mortality(%) 20.03 17.61 12.68
I
Azain, 1993, J.Anim. Sci. 71: 3011-30 J 9.
2
Fat sources fed at a level of 12% during the last three
weeks of gestation and the first week of lactation.
The results ofthis experiment suggests that
medium chain triglycerides are superior to long
chain triglycerides in reducing preweaning mortal-
ity. The difference in performance would appear to
be a reflection of the different ways in which these
fat types are metabolized. Medium chain
triglycerides are rapidly metabolized to ketone
bodies. Because ketone bodies can readily cross the
placenta and are used in the developing fetus for the
synthesis of lipid and to spare glucose, they have
the potential to improve fetal energy stores at birth
and thereby improve the piglets chances ofsurvival.
Feeding the Sow During Lactation
Introduction
Lactation is a particularly important stage ofthe
reproductive cycle. Its primary purpose is to
successfully rear a large number ofhealthy, heavy
piglets. A lactating sow may need to draw on body
fat reserves to obtain the energy she needs for
maintenance and milk production. This drain on
her body reserves causes a significant loss ofbody
weight resulting in an extended weaning to remating
interval, poor conception rates and premature
culling. Therefore, particular care must be taken to
ensure that sows are properly fed during lactation.
The importance ofmaintaining high feed intakes
during lactation has been clearly demonstrated.
The results ofa study in which lactating sows were
fed between 1.5 and 5.0 kg of feed per day are
shown in Table 6-22a. Sows receiving low levels of
feed during lactation lost significantly more weight
and depleted their backfat reserves to a much
greater extent than did sows fed higher levels of
feed. Consequently. sows fed low levels of feed
during lactation had longer weaning to conception
intervals than sows well fed during lactation. In
addition, significantly fewer sows fed low levels of
feed exhibited estrus within eight days ofweaning.
Table 6-22a. The Effect of Sow Feed Intake During Lactation on Subsequent Reproductive Performance.
Daily Feed Intake (kg)
1.5 2.2 2.9 3.6 4.3 5.0
Lactation Weight Loss (kg) 44.5 30.8 27.4 19.6 15.8 9.0
Backfat Loss During Lactation (mm) 8.9 7. L 6.4 5.7 4.2 4.0
Weaning to Conception Interval (day) 29.8 32.4 23.6 16.4 15.5 11.4
Number of Eggs Ovulated 12.2 13.3 10.9 l 3.3 11.7 12.0
Sows in Estrus Within 8 Days of 8.3 33.3 50.0 58.3 58.3 83.3
Weaning(%)
King and Dunkin, 1986, Anim. Prod. 17: 65-75.
154

173. The level of feed provided to the sow during
lactation will also affect piglet performance. Re-
search has shown that there is a direct relationship
between the amount of feed the sow consumes
during lactation and the amount ofmilk produced
by the sow (Table 6-22b). As the level of feed
intake increases, higher levels of milk production
are achieved. This increased milk production also
increases the growth rate ofsuckling piglets.
Table 6-22b. Effect of Feed Level on Milk Yield at 21
Days (kg/day).
Feed Intake (kg/day)
4.5 5.3 6.0 6.8
Parity 1 5.9 5.4 6.7 6.1
Parity 2 5.4 6.0 6.6 6.6
Parity 3 5.5 6.8 7.3 8.0
O'Grady et al., 1973, Anim. Prod. 17: 65-75.
From the foregoing discussion, it should be
evident that every effort must be made to maximize
the feed intake ofsows during lactation. By
maintaining high levels offeed intake during
lactation it is possible to reduce sow body weight
and backfat loss, increase milk yield, increase piglet
growth rate, decrease piglet mortality and improve
the sow's subsequent reproductive performance. A
general rule ofthumb is to allow 2 kg of feed per
day for the sow and an additional 0.5 kg for each
pig in the litter. For example, a sow with 10 nursing
pigs should receive at least 7 kg per day (2 + (0.5 x
10) = 7).
Despite knowledge of the benefits ofmaximizing
feed intake, many producers still experience diffi-
culty getting sows to consume sufficient feed to
avoid excessive weight loss. A recent survey from
the University of Minnesota involving 11,700 sows
on 30 farms indicated that lactation feed intakes
averaged only 5.2 kg/day. Clearly, a more concen-
trated effort is needed to increase the average
lactation feed intake ofsows.
Methods of Increasing Feed Intake During
Lactation
One method of increasing feed intake during
lactation is to ensure that the sow is not overfed
during gestation. Research has shown that there is
an inverse relationship between the amount of feed
consumed during gestation and the amount
consumed during lactation (Table 6-23). As the
level offeed intake during gestation increases, the
level offeed intake during lactation decreases.
Therefore, feed intakes during gestation should be
reduced ifexcessive, since the higher the feed
intake during pregnancy the lower the appetite will
be during lactation.
Table 6-23. Effect of Feed lntake During Pregnancy
on Feed Intake During Lactation.
Pregnancy Feed Intake {kg/day)
1.8 2.25 2.70
Pregnancy Weight Gain (kg) 55.3 70.4 82.7
Lactation Feed Intake (kg/day) 4.76 4.70 3.98
Lactation Weight Change (kg) -12.2 -19.6 -24.6
Dounnad, 1991, Livestock Prod. Sci. 27:309-319.
The level ofdietary protein has also been
shown to affect the amount of feed consumed
during lactation. The effect offeeding diets varying
between 12 and 18% crude protein are shown in
Table 6-24. Sows consuming diets containing either
12 or 14% crude protein consumed less feed and
lost significantly more weight during lactation than
sows consuming diets containing 16 or 18% crude
protein. Piglet weaning weights were also higher
when the sow received higher levels ofdietary
protein. The consumption of low protein diets
during lactation can also cause excessive delays in
heat and poor conception rates after weaning
particularly if fed to first litter sows. Therefore, in
order to maximize feed intake during lactation and
avoid problems with rebreeding, it is recommended
that a minimum of 15% crude protein (0.70%
lysine) be provided in the lactation diet. For maxi-
mum milk production, sows may require diets
which contain 0.90% or even 1.0% lysine and a
digestible energy content ofat least 3250 kcal/kg.
155

174. Table 6-24. Effect of Feeding Various Levels of Protein During Lactation on Sow Feed Intake and Body
Condition.
12.0
Dietary Protein Level (%)
14.0 16.0 18.0
Sow Feed Intake (kg/day)
Sow Weight at Farrowing (kg)
Sow Weight at Weaning (kg)
Sow Weight Change (kg)
Piglet Weaning Weight (kg)
Mahan and Grifo, 1975. J. Anim. Sci. 41: 1362-1367.
3.5
152.2
126.8
-25.4
5.5
4.6
140.9
130.0
-10.9
6.1
5.5
143.6
147.3
+3.7
6.2
5.8
145.9
152.3
+6.4
6.8
Sows will consume more feed if fed twice rather
than once daily. Consumption is likely to increase
further if they are fed even more frequently. ln a
study conducted by the NRC-89 Committee on
Confinement Management ofSwine, sows were
allowed unlimited access to feed either once or
three times a day. Sows fed three times a day
consumed a total of I08.4 kg of feed during lacta-
tion while those fed only once a day consumed
101.6 kg offeed. In addition, weight loss during
lactation was reduced for the group ofsows fed
three times a day (22.5 versus 28.5 kg of body
weight lost).
It has been well demonstrated that sows will
consume more ofa wet feed than they will of a dry
one. The results ofone experiment are presented in
Table 6-25 and it can be seen that sows fed a wet
feed consumed approximately I 0% more feed than
sows fed a dry one. Although it would be impracti-
cal for most producers to convert their operations to
a wet feeding system, the simple act ofmounting
the water nipple in the farrowing crate directly over
the feed hopper can help to stimulate sow feed
intakes. However, care should be taken to clean the
feeder on a regular basis in order to prevent molds
from developing on the wet feed.
Use of a small feeder fitted to the front of the
farrowing crate may allow the sows to be fed ad
libitum. However, it is important that the feeder be
properly designed. Feeders which are improperly
designed may restrict the ability ofsows to con-
sume adequate amounts offeed. ln general, sows
prefer large, open 'bowel type' feeders with no
bars, rods or other gimmicks to restrict access to
feed.
Feed Intake (kg/day)
Energy Intake (MJ DE/day)
Lactation Weight Loss (kg)
4.7
62.3
29.8
5.3
69.3
23.2
Table 6-25. Effect of Method of Feeding on Sow Feed
Intake and Weight Change During Lactation.
Dry Feed Wet Feed
The method of feeding can also affect intake. For
example, use ofa pelleted diet has been shown to
increase sow feed intake during lactation. Pelleted
rations also tend to reduce the amount of feed
wastage. Since very few producers have the ability
to pellet rations on the farm, the advantages of
feeding a pelleted diet are only available to produc-
ers purchasing a commercially formulated lactation
ration.
O'Grady and Lynch, 1978, J. Agric. Res. 17: l-6.
A lactating sow can consume as much as seven
gallons ofwater per day. It is important that the
water supply of the sow not be restricted.
Inadequate amounts ofdrinking water will certainly
cause the sow to reduce feed intake. Many water
nipple drinkers in farrowing crates do not supply
adequate quantitites ofwater. Although some
references suggest a minimum flow rate of2.0 L
per minute, recent data suggest that 0.6 L is
156

175. sufficient. The only difference between the two
flow rates is a large waste ofwater at the 2.0 L per
minute flow rate. Waterer type may affect feed
consumption. University ofMinnesota studies
revealed that daily feed consumption was about 0.3
kg less when lactating sows were provided water via
nipples compared with a drinking cup.
The use offlavors in animal feeds has increased
considerably in the past decade as more attention is
being paid to palatability. Many experiments have
been conducted using feed flavors in the hope of
increasing the feed consumption ofsows during
lactation. The productsused have ranged from
simple spices and tonics to aroma modifiers, sweet-
eners, flavor intensifiers and artificial flavors as
well as certain natural feed ingredients.
The results of two experiements in which sow
diets were supplemented with a flavor enhancer are
summarized in Table 6-26. Sows fed diets supple-
mented with a flavor enhancer consumed approxi-
mately 7% more feed and lost 30% less weight
during lactation than did sows fed the control diet.
In addition, there was a slight reduction in piglet
mortality as well as an increase in piglet weaning
weight as a result ofincluding the feed flavor in the
sow's diet. Although these results indicate that
flavor additives can be used to attract sows to their
diet, increase feed intake and reduce sow weight
loss during lactation, producers should be aware
that very little is known on what specific flavors
pigs find attractive. Since flavours tend to be
expensive feed ingredients, considerable caution
should attend their use in sow diets.
The effective environmental temperature ofthe
farrowing room is one of the most critical factors
affecting feed intake in lactating sows and many
producers maintain their farrowing room at too high
a temperature. Table 6-27 shows the results ofan
experiment in which sows were housed in farrowing
rooms maintained at 27°C or 2 I °C. Sows main-
tained at the lower temperature consumed more
feed, lost less weight and weaned heavier piglets
compared with those housed at the higher tempera-
tures.
In order to stimulate feed intake, attempts should
be made to cool down the farrowing room. If
building a new barn, producers might consider the
installation of snout coolers or drip cooling. Snout
coolers with an airspeed of0.3 m/sec have been
shown to increase feed intake by 250 g/day while
drip coolers, providing 2 litres per sow per hour
(running for 3 minutes in a JO minute cycle), have
also been effective in increasing feed intake. How-
ever, it must be remembered that ifthe temperature
ofthe farrowing room is to be decreased, supple-
mental heat must be provided for the piglets.
An additional consideration regarding lowering
the temperature ofthe farrowing room is to ensure
that the building is properly insulated. The standard
insulation specification for the roof is 0.4W/m2/°C
and for walls 0.5W/m2/°C. The maximum ventila-
tion rate of the farrowing room should also be
checked to ensure adequate airflow. Although this
may not necessarily cool the sows, fresh, non-
gaseous air is beneficial in stimulating appetite.
Pigs Born Alive 9.9
Pigs Weane 8.4
Mortality(%) 14.9
Sow Feed Intake (kg/day) 4.8
Lactation Weight Loss (kg) 15.6
Weaning to Estrus Interval (days) 7.5
9.9
8.9
9.9
5.2
10.9
8.3
The farrowing floor surface also influences heat
loss and therefore could affect feed intake. Sows
housed on plastic-coated, expanded metal or woven
wire floors consumed about 0.5 kg less than sows
housed on highly conductive floor surfaces such as
metal (ie Tri-bar) or concrete.
Energy intake can be affected by increasing the
caloric density of the diet. Use ofhigh density diets
is particularly effective in maintaining energy
intakes during hot weather. Incorporating fat or oil
as a partial substitute for carbohydrate energy will
reduce the heat increment ofthe diet and thus allow
sows to consume more energy in hot weather.
157
Control Flavour
Moser et al. 1986. Minnisota Swinea Research Report.
pp 53-56.
Table 6-26. Performance of Sows Fed Artificial
Flavours During Lactation.

176. Table 6-27. Effect of Environmental Temperature on
Feed Intake and Weight Loss of the Sow and Weight
Gain of the Litter,
Reducing the protein level ofthe diet and using
synthetic amino acids to provide the proper balance
of amino acids can also achieve this purpose.
Nutrients Required During Lactation
Energy
The daily energy requirement of the sow during
lactation includes a requirement for maintenance
and a requirement for milk production. The mainte-
nance energy requirement ofthe lactating sow is
assumed to be the same as that for the gestating sow
and is estimated to be I IO kcal of DE per kg of
body weight 15• This is sometimes a difficult calcu-
To properly monitor lactation feed intakes, it is
recommended that producers keep track of the
individual feed intake ofsows using a card similar
to that shown below (Fiqure 6-5). Use ofsuch
cards creates an easily interpreted, graphic display
of the pattern of intake of each sow. lt is only
through the use of a proper recording scheme that
producers will be able to detect when alterations in
feed intake occur and take steps to intervene when
reductions occur.
It is evident from the above discussion that no
single energy level will apply to all sows under all
conditions. The following table indicates how
daily energy requirements are altered by factors
such as sow body weight, litter size and piglet
growth rate (Table 6-28).
Table 6-28 indicates that a 142.5 kg sow nursing
12 piglets, gaining 240 g/day will require 8.34 kg of
a diet containing 3300 kcal ofDE in order to meet
its energy requirements. Unfortunately, our modern
genotypes ofsows will often not consume this
amount of food. As a consequence, such sows with
a high level ofproductivity may not consume
sufficient feed to meet their energy requirements
and will have to "milk offtheir backs" in order to
meet the energy needs ofthe nursing litter.
The energy level required for milk production is
estimated to be 2 Meal of DE per kg of milk pro-
duced. This is calculated by assuming that the gross
energy of milk is 1.3 Meal DE per kg and that the
milk is produced with a 65 percent efficiency of
utilization ( 1.3 Meal+ 0.65 = 2.0 Meal). The milk
production of a sow can be estimated from piglet
weight gain. Since it takes about 4 g of milk to
produce 1 g ofpiglet gain, total milk production can
be calculated by multiplying the daily weight gain
of a litter by four. As an example, a litter of 9
piglets gaining 240 g/day would suggest a daily
milk production of 8.64 kg (9 x .24 x 4). This level
ofmilk production would require an energy intake
of 17.28 Meal DE (8.64 kg x 2 Meal/kg milk
produced).
lation for producers to make and most nutritionists
use a thumb rule of I% ofa sow's body weight to
estimate maintenance requirements. Therefore, a
165 kg sow requires 1.65 kg of feed for mainte-
nance. If we assume a energy value of the feed of
3200 kcal then this level offeed intake would
supply 5.28 Meal ofenergy which comes reason-
ably close to the 5.06 Meal of energy we would get
by using the above equation (See Table 6-1 I).
5.2
14.0
7.0
21.0
6.2
4.6
Temperature
27°C 21°C
Lynch, 1978.
Recent evidence has suggested that sows exposed
to longer periods of lighting during the day may
have higher feed intakes. Increased weaning
weights and improved rebreeding performance have
been observed when sows were housed in farrowing
rooms with 16 hours of light per day in comparison
with 8 hours of light per day. Automatic timing
devices are currently available which allow produc-
ers to control the duration oflighting in the farrow-
mg room.
Sow Feed Intake (kg/day)
Sow Weight Loss (kg)
I IO Days to Weaning
Piglet Weight at 28 Days (kg)
158

177. Table 6-28. Estimated Daily Energy Requirements of Lactating Sows.
Sow Body Weight (kg) 142.5 142.5 217.5 217.5 280 280
Number of Suckling Piglets 8 12 8 12 8 12
Daily Gain ofPiglets (g/day) 200 240 200 240 200 240
Estimated Milk Yield (kg/day)' 6.4 11.5 6.4 11.5 6.4 11.5
Energy for Maintenance (Mcal/day)2
4.53 4.53 6.23 6.23 7.52 7.52
Energy for Milk Production (Meal/day)? 12.80 23.00 12.80 23.00 12.80 23.00
Daily Energy Requirement (Meal/day) 17.33 27.53 19.03 29.23 20.32 30.52
Daily Required Feed Intake (kg/day)' 5.25 8.34 5.76 8.85 6.15 9.25
1
Milk yield estimated from litter gain/day x 4
2
Sow energy needs for maintenance estimated from BW75
x I IO kcal per kg (see Table 6-10)
3
Energy for milk production estimated from milk yield x 2 MCal/kg milk produced
"Feed intake required based on 3300 kcal DE/kg diet
Using the above example, assume that the sow is
only consuming 6.5 kg offeed per day. In this
situation, the sow will have an energy deficit of
6006 kcal/day (1.82 kg x 3300 kcal). It has been
calculated that for every kg of weight loss by the
sow, 11,200 kcal of DE equivalent are released.
Therefore, to make up the 6006 kcal/day deficit will
require a maternal weight loss of 536 g/day or about
15 kg during a 28 day lactation. As a rule, it is
desireable to keep maternal weight loss during a 28
day lactation to less than 10 kg and as a
consequence, steps would have to be taken to
increase lactational energy intake by the sow or
reduce the energy demands for lactation through
cross fostering.
Amino Acids
The amino acid requirements of lactating sows
have been the subject ofa considerable amount of
research during the past decade and it is now
evident that the current estimates of requirements in
the NRC tables are inadequate to allow high pro-
ducing sows to perform to their genetic potential.
This is likely a reflection ofimprovements in sow
milking ability due to increased selection pressure
on this trait by breeding companies.
An estimate ofthe amino acids needs ofthe
lactating sow can be obtained by examining the
amino acid composition of sow's milk. By using
the daily milk yield ofthe sow (based on piglet
SOWID:
LACTATION FEED
INTAKE RECORD
/Q,J(i PARITY: _!/___ DATE:Farrowed'#s/O�/Q/ Weaned��
NO: Born Alive l2. w.� Ll FEED INTAKE: To1al �I Per day 7.3/r...
... . . . . . . .. . . . . • .. • L::... . .. . . ..::,.1
I I I � ;-r... ..,.
...._ �
. ; .. .,, .,
-. I ti I
I I t/1 ti i I I
. I ti l
. I ,I I I I
. I I l
,I I I
I'll" I I
. ti
' I I -
.... , I l
M
I 2 J
'
.,
'
., " ,,.,,,,�SS5'. � r s r S" (' S" I-
.. ii I I 1 J "1¥ " s f s ..,,. ,,. .,. "' r s r r r r
,_ ,_
u, 3.l!_' .!J� ,, , 'l•l4• 't' 't' ,, "P ,, I# lo ID II> "' /()
,_.._
Figure 6-6. Example of a Card for Monitoring Lactation Feed Intake.
159

178. weight gain shown above) one can calculate the
amounts of the essential amino acids which are
secreted in milk on a daily basis. The efficiency of
utilization ofamino acids for milk production has
been estimated at 80% and most lactation diets
would have a digestibility coefficient of
approximately 80%. Therefore, by dividing the
amounts of amino acids secreted into milk by 0.64
(80% efficiency x 80% digestibility), one arrives at
the total amount ofamino acids required to support
this level of milk production. Examples are shown
in Table 6-29.
The total dietary amino acid needs of the lactating
sow can be determined by adding the amino acids
required for maintenance (see table 6-11) to those
need for lactation (Table 6-29). Examples are given
for three weights ofsows and four daily milk yields
but can be calculated for any situation using the
figures provided.
The most important animo acid for sows in lacta-
tion is lysine. Dividing the daily lysine requirement
by the expected feed intake ofthe sows will show the
required level of lysine in the diet. For example, a
142.5 kg sow with a litter gaining 2250 g/day (i.e.,
producing 9 kg ofmilk per day) will require 55.9 g of
lysine per day. If the sow is consuming 7 kg of feed,
then the diet will need to provide 0.79% lysine (55.9
g + 7000 g = 0.79%).
Obviously, it is not possible to formulate one diet
that will meet the lysine requirements for each and
every sow in a herd. In addition, since the objective
oflactation feeding is to maximize feed intake, vary-
ing the level of feed provided is not available as a
means ofvarying the lysine intake ofindividual sows.
Underpractical feeding conditions, it is suggested that
producers formulate two rations to be fed during lac-
tation. One to be fed to first and second parity sows
(these sows typically cannot consume adequate feed
and therefore this dietwouldbe formulated with higher
lysine levels) and one for the remainder of the herd.
Table 6-29. Estimated Daily Amino Acid Requirements for Milk Production by the Sow (g/day).
Composition
ofMilk (%)1 Daily Milk Production (kg/day)2
5 7 9 11
S3 R4 s R s R s R
Arginine 5.1 12.7 19.9 17.8 27.9 22.9 35.8 28.0 43.8
Histidine 2.8 7.0 10.9 9.8 15.3 12.6 19.7 15.4 24.1
Isoleucine 4.5 11.3 17.6 15.7 24.6 20.2 31.6 24.7 38.7
Leucine 8.7 21.7 34.0 30.4 47.6 39.1 61.2 47.8 74.8
Lysine 7.8 19.5 30.5 27.3 42.6 35.1 54.8 42.9 67.0
Sulfur AA 3.3 8.3 12.9 11.5 18.0 14.8 23.2 18.1 28.4
Aromatic 8.3 20.7 32.4 29.0 45.4 37.3 58.4 45.6 71.3
Threonine 4.2 10.5 16.4 14.7 22.9 18.9 29.5 23.1 36. l
Tryptophan 1.2 3.0 4.7 4.2 6.6 5.4 8.4 6.6 10.3
Valine 5.6 14.0 21.9 19.6 30.6 25.2 39.4 30.8 48.1
I
Adapted from Speer (1990). Partitioning nitrogen and amino acids for pregnancy and lactation in swine: A review. J.
Anim. Sci. 68: 553-56 l.
2
Daily milk production calculated by multiplying daily weight gain oflitter x 4.
3Secreted
"Required
Based on sow producing milk with 5% protein. Assumed absorbed amino acids used at an efficiency of 80% for
milk production and diet had 80% digestibility.
160

179. Table 6-30. Estimated Total Daily Amino Acid Requirements of Lactating Sows (g/day).
Sow Weight (kg) 142.5 217.5 280
Current
Daily MilkYield 5 7 9 11 5 7 9 11 5 7 9 11 NRC'
Amino Acid Requirement (g/day)
Arginine 19.9 27.9 35.8 43.8 19.9 27.9 35.8 43.8 19.9 27.9 35.8 43.8 21.2
Histidine 10.9 15.3 19.7 24.1 10.9 15.3 19.7 24.1 10.9 15.3 19.7 24.1 13.2
Isolcucine 18.8 25.8 32.9 39.9 19.3 26.3 33.3 40.4 19.6 26.6 33.7 40.7 20.7
Leucine 34.8 48.4 61.9 75.6 35.1 48.7 62.3 75.9 35.4 48.9 62.5 76.1 25.4
Lysine 31.5 43.7 55.9 68.0 31.9 44.0 56.3 68.4 32.2 44.4 56.6 68.7 31.8
Sulfur Amino Acids 13.9 19.1 33.7 29.4 14.4 19.5 24.7 29.8 14.7 19.8 24.9 30.I 19.1
Aromatic 34.3 47.3 60.2 73.2 35.0 47.9 60.9 73.9 35.6 48.5 61.5 74.5 37.1
Threonine 18.0 24.6 31.1 37.7 18.6 25.2 31.7 38.3 19.1 25.6 32.2 38.7 22.8
Tryptophan 4.9 6.8 8.6 10.5 4.9 6.8 8.7 10.6 5.0 6.9 8.8 10.6 6.4
Valine 22.7 31.5 40.2 48.99 23.0 31.8 40.6 49.3 23.3 32.0 40.8 49.5 31.8
I
Based on a 165 kg sow consuming 689 g/day crude protein.
Vitamins and Minerals
There has been surprisingly littleresearch conducted
on the vitamin and mineral requirements ofsows dur-
ing lactation alone. The available data suggests that
the lactating sows requirements do not differ appreci-
ably from those of the gestating sow and therefore
the nutrient levels suggested in Tables 6-12 and 6-13
are recommended.
Feeding the Sow at Weaning
There is a great diversity ofopinion as to how sows
should be fed and managed from weaning to
rebreeding. Many producers believe that withhold-
ing feed and water for 24 to 48 hours after weaning
will dry the sow offmore rapidly, leading to a shorter
interval between weaning and rebreeding. However,
others feel that moderate to high levels of feed will
give the best results.
A Texas study investigated the effects of feed and
water deprivation prior to weaning, on the number of
days to successful service. The results of this trial
indicate that feed and water deprivation at weaning
prolonged the weaning to service interval (Table 6-
31). Therefore, it would appear that the most effec-
tive way to dry off a sow is to maintain them on a
moderate level offeed and allow milk to accumulate
in the udder. The resulting increase in intramammary
pressure will very effectively and rapidly stop milk
secretion and stimulate a rapid return to estrus.
Table 6-31. Effect of Feed and Water Deprevation, Prior to Weaning, on Days to Successful Service After
Weaning.
Hours of Deprivation
Prior to Weaning
Feed 0 48.0 0 48.0
Water 0 0 24.0 24.0
Days to Successful Service 6.0 11.9 9.1 12.8
Number not Showing Estrus Within
21 Days Postweaning 0.0 5.0 3.0 5.0
Orr et al., 1981, Anim. Prod. 15: 259-264.
161

180. Feeding the Sow Between Weaning
and Rebreeding
The level of feed intake selected from weaning
and mating should allow the release ofsufficient
ova, their successful fertilization and implantation.
Many producers find that gilts which havejust
weaned their first litter are difTicult to rebreed. This
is generally due to the poor body condition of first
litter sows and the stress of competing with older
sows after weaning. The best solution is to feed
sows better during lactation than to try to catch up
later on. However, supplying high levels (3.5 - 4.0
kg/day) of feed to gilts in poor condition from
weaning to rebreeding will improve conception
rates and reduce the number ofdays to rebreeding
(Table 6-32). After breeding, feed levels should be
reduced to maintenance levels in order to prevent a
high incidence ofembryo mortality.
Table 6-32. The Effect of Feed Intake During the
Weaning to Remaining Interval on the Reproductive
Performance of Gilts and Sows.
Feed Intake(k;g/day)
1.8 2.7 3.6
Weaning/Estrus
Interval (days) Gilts 21.6 12.0 9.3
Sows 4.9 4.7 5.0
Conception Rate (%) Gilts 58 75 100
Sows 100 87 100
Subsequent Litter Size Gilts 9.4 10.1 11.6
Sows 12.6 11.8 12.2
Adapted from: Brooks and Cole, 1972, Anim. Prod. 15:
259-264, and Brooks et al., 1975, Anim. Prod. 20: 407-
412.
Flushing does not work with older sows. The
purpose of a high level of feeding after weaning is
to increase ovulation rates and thereby increase the
subsequent litter size. However, since ovulation
rate is not usually a limiting factor for sows, even if
the ovulation rate is increased, an improvement in
litter size is not usually forthcoming. A daily feed
intake ofapproximately 2.7 kg between weaning
and remating is generally sufficient to allow sows in
reasonable condition to achieve high conception
rates and good litter size.
During hot weather, conception rates are often
reduced. There is some evidence to show that
feeding vitamin fortified diets to the breeding herd
may improve conception rates during periods of
elevated temperatures. In a recent study, sows were
fed higher than recommended levels ofvitamin A
( I 50% NRC), vitamin B-12, pantothenic acid and
choline during periods of hot weather. The concep-
tion rate ofthe vitamin fortified group increased
from 52.8% to 76.0%.
Feeding Boars
Introduction
The boar is often the forgotten member ofthe
breeding herd and there has been surprisingly little
research conducted to determine their nutritional
requirements. Most tables ofnutrient requirements
group boars together with dry sows and assume that
a diet that meets the requirements ofsows during
gestation will also be satisfactory for the herd sire.
Nutrition of Boars During Rearing
(20 -100 kg)
Young boars are usually selected to be herd sires
according to an index which includes such charac-
teristics as growth rate. appetite, feed efficiency,
lean tissue growth rate and carcass quality. As a
consequence, young boars need to be fed high-
energy and nutrient dense diets ad libitum in order
to allow for the accumulation of meaningful per-
formance data for use in selection programs. Dur-
ing the period from birth to 50 kg body weight, the
boars potential for lean tissue growth appears to be
beyond the upper limit ofappetite. This means that
high energy diets can be fed ad libitum without
excessive fat deposition or decline in feed effi-
ciency and energy levels of at least 14 MJ DE/kg
(3344 kca1/kg) diet are recommended. From 50 to
I 00 kg liveweight, the boars potential for protein
deposition lies within the limits ofappetite and
excess energy levels may affect performance.
Australian data indicate that the maximum rate of
protein deposition occurs with energy levels of 33
MJ DE/day (7883 kcal/day). Ifthe potential ad
libitum feed intake of the boar is known, then the
162

181. required energy content ofthe diet can be calculated
by dividing this energy level by the potential feed
intake.
The protein requirement ofgrowing boars is
greater than that ofbarrows or gilts since boars gain
faster, are more efficient and have less backfat.
Average daily gain and feed efficiency are maxi-
mized for growing boars at levels of 20% protein
during the growing period (20-55 kg) and 18%
crude protein during the finishing period (55-100
kg). In addition, developing boars require 0.15% to
0.25% more lysine than barrows. Data from the
University ofKentucky indicate that the lysine
requirement of 35-60 kg boars is 0.86% while that
of 60-100 kg boars is 0.74%. These levels are
higher than those recommended by the NRC.
The developing boar may require higher levels of
calcium and phosphorus than the levels fed to
market animals since the tendency to show leg
weakness may be exacerbated by high growth rates
and by feeding to appetite. Calcium and phospbo-
ms levels of0.75% and 0.60% respectively are
recommended during the growing period and drop
to 0.65% and 0.50% by the time the boar is ready
for breeding. A summary of nutrient requirements
for developing boars is presented in Table 6-33.
The experimental evidence suggests that nutrition
during rearing can influence both the age ofpuberty
and the rate ofsexual development but these are
unlikely to be impaired under current feeding
regimes and practices. Under normal breeding
conditions, boars attain puberty between 5 and 8
months of age when they weigh 80-120 kg body
weight. Age is more important than body weight in
determining the onset of puberty. Although a 30%
reduction in feed intake has been shown to cause a
42 and 30 day delay in puberty for purebred and
crossbred boars. unless severely undernourished,
this restriction does not appear to impose any long
lasting, damaging effects upon reproductive capac-
ity other than the obvious effects on the growth and
body size of the animal. In practise, most young
boars are offered feed to appetite during rearing and
at this feeding level there is unlikely to be any
negative effects upon sexual development or subse-
quent reproductive capacity.
Table 6-33. Nutrient Requirements of Developing
Boars (20-100 kg).
Weight of Boar
20-55 55-100 120-
Breeding
Energy (MJ/day) 29 33 25
Protein(%) 20 18 14
Lysine(%) 1.0 0.8 0.65
Tryptophan (%) 0.17 0.14 0.12
Threonine(%) 0.65 0.60 0.50
Methionine+ Cystine (%) 0.45 0.35 0.40
Calcium(%) 0.75 0.70 0.65
Phosphorus(%) 0.60 0.55 0.50
Salt(%) 0.25 0.25 0.50
Zinc (mg/kg) 75 50 75
Iron (mg/kg) 75 50 75
Manganese (mg/kg) 20 20 20
Copper (mg/kg) 6 5 6
Selenium (mg/kg) 0.15 O.IO 0.10
Vitamin A (lU/kg) 3000 2000 4000
Vitamin D (ill/kg) 300 200 400
Vitamin E (IU/kg) 18 15 20
Vitamin K (mg/kg) l.5 1.0 2.0
Riboflavin (mg/kg) 4.0 3.0 5.0
Niacin (mg/kg) 30 25 35
Pantothenic Acid (mg/kg) 15 12 20
Choline (mg/kg) 400 300 500
Vitamin B12
(ug/kg) 15 10 20
Biotin (ug/kg) 50 50 100
Adapted: Wahlstrom, 1991. Swine Nutrition pp 517-
526.
Nutrition of the Working Boar
The daily energy requirements for working boars
can be assessed as the summation ofthe following
components: maintenance, body gain, semen
production, mating activity and the requirement for
extra heal production when kept below their lower
critical temperature. Estimates have been derived
from the factorial principle of nutrient partitioning
and range from 29 to 41.5 MJ DE/day with an
additional 3% for each I °C decrease in temperature
below an environmental temperature of20°C.
163

182. The energy requirements for maintenance can be
calculated in a similar manner to those of the
gestating sow using a value of .4 LS MJ DE per kg
body weight:". The energy requirements for growth
are more difficult to calculate because there has
been very little research conducted to determine the
optimum growth rate of working boars.
Overfeeding is undesireable because overfeeding
may reduce I ibido and may increase the risk ofleg
weakness. Ln addition, overfeeding can increase the
size and weight ofthe boar to the point where the
boar is no longer compatible with the sows in the
herd and must be culled. Given their high purchase
price, early culling ofboars is clearly detrimental.
However, underfeeding may affect reproductive
characteristics such as number ofsperm cells and
the fertilizing capacity of the sperm cells.
One ofthe few attempts to suggest an optimum
growth rate for working boars comes from recent
research at the University ofWageningen. Dutch
workers recommend a moderate growth rate (400 gJ
day) for young boars (150-250 kg) and a reduced
weight gain (200 g/day) in mature boars (250-400
kg). Their research suggests an energy cost for
growth of 32.8 MJ per kg weight gain. The energy
requirements for reproduction (semen production
and mating activity) amount to about 18 kJ per kg:"
which amounts to less than 3% of the maintenance
cost of the boar. Therefore, this energy cost is
usually ignored in calculating the daily energy needs
ofthe working boar. The energy requirements of
boars ofvarious body weights are calculated in
Table 6-34.
Table 6-34. Energy Requirements ofWorking Boars.
The results ofthese calculations indicate that
working boars should be fed between 2.6 and 3.0
kg per day. The exact amount given to the boar will
depend on breeding load, climatic conditions, body
weight and condition. Boars should be individually
fed, twice a day. This allows for a daily check of
the health and vigor ofthe boar and an adjustment
in the amount of feed provided where necessary.
Fresh water should be provided at all times.
Several studies have indicated the importance of
protein and more specificaUy the amino acids
lysine, methionine and cystine on the number of
sperm cells produced. There appears to be a mini-
mum level ofprotein neccessary to ensure maximal
sperm production since low protein levels have
been shown to reduce the number ofsperm cells
ejaculated. A crude protein content of 14% with
lysine and sulfur containing amino acid levels of
0.65% and 0.44% are recommended.
Calcium and phosphorus are the most important
minerals to consider in the context ofthe nutrition
ofthe working boar as they are crucial not only to
optimal growth rate but also to bone mineralization
and hence overall soundness of the limbs. It is
generally accepted that higher levels ofcalcium and
phosphorus are required for optimum bone miner-
alization as opposed to maximizing growth rate.
Soundness oflimbs is an important index to con-
sider as foot-related problems are a major contribu-
tory factor to loss of libido and the inability ofthe
boar to mount a sow. It has been reported that
boars which were fed 150% ofNRC recommenda-
Liveweight (kg)
Weight gain (g/day)
Maintenance Energy (MJ/day)1
Energy for Growth (MJ/day)2
Total Energy (MJ/day)
Daily Feed Required (kg/day)!
150
500
17.8
16.4
34.2
2.6
200
400
22.1
13.1
35.2
2.7
250 300 350 400
300 200 100 50
26.1 29.9 33.6 37.1
9.8 6.6 3.3 1.6
35.9 36.5 36.9 38.7
2.8 2.8 2.8 3.0
'Calculated using .415 MJ per kg BW15
2
Calculatcd using 32.8 MJ per kg weight gain
'Assumes energy content of feed is 13 MJ/kg
Adapted from Kemp, 1989.
164

183. Table 6-35. Composition of Diets for Adult Boars.
Adapted from Aherne, F. 1995. Pig Letter 15:16.
fibrous foods. For example lesions of the
esophagus are common in cereal fed animals
resulting in a reduced feed intake and poorer repro-
ductive performance. Increasing the fibre content
ofthe diet has been shown to reduce the severity of
such lesions.
In summary, the energy and protein needs of a
typical boar (i.e., one of 18-24 months and 175-250
kg liveweight maintained in a thermoneutral envi-
ronment) are satisfied by a daily feed allowance of
2.6-3.0 kg of a diet containing around 13 MJ DE/kg
and 140 -160 kg ofcrude protein. For every 1°C
that the house temperature drops below 21°C a boar
on a solid unbedded floor should be offered an
extra I OOg of food daily. For a boar well bedded
on straw, this rule would apply below 17°C.
13.0 13.0
15.0 14.0
0.7 0.55
0.47 0.40
0.80 0.75
0.70 0.60
150-200 kg 200-350kg
Dietary Energy, MJ DE/kg
Protein,%
Lysine,%
T.S.A.A., %
Calcium,%
Phosphorus, %
It has also been suggested that the working boar
has no additional requirement for vitamins above
those ofthe breeding sow. However, the role of
biotin in the diet ofboars is becoming increasing
important as a result ofits association with foot
lesions and the attendant implications this bas for
reproductive performance in the boar. Biotin is an
essential water soluble sulfur containing vitamin.
Supplementation ofthe diet with biotin has been
shown to significantly strengthen the hoof. The
precise mode of action of biotin in the prevention of
foot lesions is still uncertain. It is known that biotin
increases the compressive strength and hardness of
the hoofwall which decreasing the hardness ofthe
heel bulb tissue. A soft heel bulb presumably acts
as a cushion, minimizing stresses and absorbing
strain energy. There is also the suggestion that
vitamins E and C may be of special importance in
the diet ofstress susceptible breeds.
Zinc has an established role in spermatogenesis
since zinc deficiencies are implicated in the retarda-
tion ofthe leydig cells. a reduced response to
leutinizing hormone and a reduction in testicular
steroidogenesis. A level of I00 mg/kg is recom-
mended. Boars show no additional requirements
for the other major minerals in relation to sows.
tions for dietary calcium and phosphorus and
thicker-walled metacarpals which had greater
strength than boars fed I 00% of recommendations.
A major practical problem in feeding boars is that
the low level of intake may result in hunger, frustra-
tion, abnormal behaviour and generally poor wel-
fare. The use ofbulky or fibrous feeds may over-
come these problems and improve health, provided
they supply sufficient nutrients to meet the dietary
needs of the animal. The precise role that fibre may
have in reducing hunger and increasing satiety over
a prolonged period of time may be two fold.
Firstly, the considerable bulking effect that plant
fibre produces increases overall gut fill producing a
feeling offullness and satiation. Secondly, there is
evidence to suggest that gastric emptying and
intestinal transit times may also be prolonged so
that the duration ofthis increased fullness will be
extended. There may also be positive health and
welfare advantages associated with the feeding of
165

184. Additional Reading and References
Aherne, F.X., 1991. Feeding the gilt and sow for
optimal production. Pages 455-473 ln J.M. Naylor
and S.L. Ralston eds. Large Animal Clinical
Nutrition, Mosby Year Book, St Louis, Missouri.
Azain, M.J., 1993. Effects of adding medium-chain
triglycerides to sow diets during late gestation and
early lactation on litter performance. J. Anim. Sci.
71: 3011-3019.
Brooks, P.H. and Cole, D.J., 1972. Studies in sow
reproduction. I. The effect ofnutrition between
weaning and remating on the reproductive perform-
ance ofprimiparous sows. Anim. Prod. 15: 259-
264.
Brooks, P.H., Cole, D.J., Rawlinson, P., Croxson,
V.S. and Luscombe, J.R., 1975. Studies in sow
reproduction. 3. The effect of nutrition between
weaning and remating on the reproductive perform-
ance ofmultiparous sows. Anim. Prod. 20: 407-
412.
Close, W.H. and Roberts, F.G., 1993. Nutrition of
the working boar. Pages 347-371. In D.J.A. Cole,
W Haresign and P.C. Garnsworthy, eds. Recent
Developments in Pig Nutrition 2, Nottingham
Univeristy Press, Sutton Bonington, UK.
den Hartog, L.A., Backus, G.B.C. and Vermeer,
H.M., 1993. Evaluation ofhousing systems for
sows. J. Anim. Sci. 71: 1339-1344.
Froese, C., 1987. Assessing sow body condition.
Manitoba Agric, Swine Fact Agdex No. 440-22-40.
Hoofs, I.A., 1990. Group housing ofpregnant sows
in the Netherlands. D. Kellliher, B. Lynch, M.
Martin, F. Tobin and N. Walsh eds. Pig Production
Trends for the l 990's.Proceedings of the 19th
Annual Syrnp., University College, Dublin, Ireland.
pp. 14-23.
Kemp, B., Bakker, C.M., den Hartog, L.A. and
Yerstcgcn, M.W., 1991. The effect of semen
collection frequency and food intake on semen
production in breeding boars. Anim. Prod. 52: 355-
360.
Kemp, B. and den Hartog, L.A., 1989. The influ-
ence ofenergy and protein intake on the reproduc-
tive performance of the breeding boar: A review.
Anim. Reprod. Sci. 20: 103-115.
Kemp, 8., den Hartog, L.A. and Grooten, H.J.G.,
1989. The effect of feeding level on semen quan-
tity and quality ofbreeding boars. Anim. Reprod.
Sci. 20: 245-254.
Mahan, D.C., 1990. Mineral nutrition ofthe sow:
A review. J. Anim. Sci. 68: 573-582.
National Research Council, 1988. Nutrient Require-
ments ofSwine. 9th Revised Edition, National Acad-
emy Press, Washington, D.C.
Noblet, J., Dourmad, J.Y. and Etienne, M., 1990.
Energy utiliztion in pregnant and lactating sows:
Modelling ofenergy requirements. J. Anim. Sci. 68:
562-572.
Pettigrew, J.E., 1993. Amino acid nutrition of ges-
tating and lactating sows. Biokyowa Technical Re-
view, 18 pp.
Speer, V.C., 1990. Partitioning nitrogen and amino
acids for pregnacy and lactation in swine: A review.
J. Anim. Sci. 68: 553-561.
Standing Committee on Agriculture, 1987. Feeding
Standards for Australian Livestock: Pigs. CSIRO
Printing Centre, Collingwood, Victoria, 226 pp.
Takach, M.D., and Dial, G.D., 1992. Managing the
lactating sow for optimal weaning and rebreeding per-
formance. Pages 559-573. In R.C. Tubbs and A.O.
Leman eds. TheVeterinary Clinics ofNorthAmerica:
Swine Reproduction. W.B. Saunders Company, Phila-
delphia.
Wahlstrom, R.C., 1991. Feeding developing gilts
and boars. Pages 517-526 in E.R. Miller, D.E.
Ullrey and A.J. Lewis eds. Swine Nutrition.
Butterworth-Heinemann, Stoneham Mass.
166

185. 7. FEEDING THE SUCKLING PIG
Table 7-1. Effect ofWeaning ;"eight at 25-29 Days of
Age on Piglet Performance to 78 Days ofAge.
Young piglets have a great capacity for growth,
much greater in fact, than is commonly recognized.
Growth in the suckling piglet is primarily limited by
insufficient intake ofmilk or ofalternative sources
ofnutrients. Because practical approaches for
transferring more nutrients from the sow to the
piglet are not yet available. it is the producer's job
to get more nutrients into the piglet so that growth
can be maximized.
Improving a piglet's pre-weaning growth rate
makes a major difference to the rest of its growth
cycle. There is a strong positive correlation
between weaning weight and post-weaning
performance (Table 7-1 ). Compared with their
lighter contemporaries, piglets that are weaned at a
body weight of7 kg or heavier are less susceptible
to post-weaning diarrhea, will have less post-
weaning growth lag and will require a less complex
diet after weaning.
The immunoglobulin concentration of sow's
milk declines very rapidly after farrowing. In
addition, as a result ofa process known as gut
closure, piglets rapidly lose their ability to absorb
immunoglobulins. Ifpiglets do not suckle during
their first 24 hours. they have a greatly reduced
chance ofobtaining adequate immune protection
and may not survive. A point to remember:
immunoglobulins present in the colostrum are
effective only against diseases to which the sow has
been exposed. Ifpregnant sows are brought into a
new barn and fan-ow within 21 days, they may not
protect their offspring against bacteria present in the
new barn. Scouring in newborn piglets is one
symptom of inadequate sow exposure to disease-
causing organisms.
The Importance of Colostrum
The first requirement for successful piglet
feeding is to ensure that each newborn receives an
adequate supply of colostrum. Colostrum is the
first milk produced by the sow after parturition; its
function is to provide nutrients and other essential
substances in a highly concentrated form. In
addition, colostrum helps to increase disease
resistance in piglets by providing immunization
with immunoglobulins (also called antibodies).
Immunoglobulins are proteins, absorbed by the
newborn pig's gut, that provide protection against
disease.
It is now recognized that the nursing piglet has much
greater potential for growth than was previously
acknowledged. The problem is to supply sufficient
nutrients to the piglet to allow greatest genetic potential.
Photo 7-1.
454
529
daily
gain (g/d)
30.40
35.60
78 day
weight(kg)
6.14
7.95
Weaning
weight(kg)
Another point in favour of increased pre-
weaning growth rate is decreased pre-weaning
mortality. Pre-weaning mortality is one ofthe
major factors reducing swine production efficiency.
A pre-weaning mortality of5% is possible, but on
most commercial farms, 7 to 30% of piglets born
alive do not survive until weaning. The majority of
deaths occur within 72 hours ofbirth, with at least
50% occurring in the first 24 hours. Often pre-
weaning mortality is caused by a number of factors,
many of which are related to insufficient energy
intake (milk consumption) and excessive body heat
losses. fn order to minimize energy losses, nursing
piglets should be provided with a warm and draft-
free creep area in the farrowing crate or pen.
167

186. Iron injections should be administered in the neck to
avoid staining the ham at the injection site.
Although iron supplementation is crucial to the
suckling piglet's we11-being, excess iron may
increase the incidence ofscouring and susceptibility
to bacterial infections. Iron is generally found
tightly bound to protein in the suckling pig's body.
This binding limits how much iron is accessible to
bacteria. However, if iron is present at a level
beyond the capacity ofthese proteins to bind it,
pathogenic bacteria may proliferate. Therefore,
take care to ensure that piglets are provided with
adequate, but not excessive, iron supplement. Lron
injections occasionally result in the rapid death of
some piglets. which may indicate a vitamin E and
selenium deficiency.
Water Requirements
Piglets require water immediately after birth and
should be offered water from their first day,
especially in warm conditions. Providing drinking
water to very young piglets does not reduce their
motivation to suckle; rather, they benefit from
supplemental drinking water, especially if the sow
milks poorly and they do not consume enough
water in the limited amount of milk they receive.
Litters that gain poorly during the first one to three
days after farrowing drink more water than faster
growing litters. Provision ofa fresh water source is
also beneficial in reducing stress that piglets
Currently, commercial products that contain
imrnunoglobulins and highly digestible energy
sources are available. An oral dose ofthese prod-
ucts may reduce a newborn piglet's need for its
mother's colostrum.
To ensure all piglets acquire colostrum, Photo 7-2.
producers should take the time to observe litters
shortly after farrowing and assist weak piglets to
suckle by giving them access to the sow's udder.
One way to give access is called "split suckling''.
Shortly after birth, halfthe piglets are removed
from the sow and are kept in a warm, dry box. The
two halves of the litter are rotated on and off the
sow to give individual piglets maximum
opportunity to suckle and receive colostrum.
The Need for Supplementary Iron
Based on nutrient content and availability, sows'
milk is generally accepted as the nearly perfect food
for the very young piglet. The only nutrient that is
present in sub-optimal levels is iron. Because of
this deficiency, piglets require supplementary iron
or they will become anemic and die.
Another way to ensure piglets receive some
colostrum is to keep a supply of cow colostrum in
the freezer and give weak and unthrifty piglets an
oral dose (using a small syringe) ifthey have had
inadequate suckling of their mother's colostrum.
The iron deficiency in sow's milk can be over-
come by the administration of iron dextran either
orally or by an intramuscular injection. The amount
of iron required to meet their requirements largely
depends on the age at which the piglets are to be
weaned. Researchers have calculated that piglets
require approximately 10 mg of iron per day to
allow growth at their maximum rate. Therefore, if
piglets are to be weaned at three weeks, a single
injection of 150-200 mg of iron dextran is suffi-
cient. However, if piglets are to be weaned later, a
booster shot may be required between days 14 and
21. A means to check the adequacy of iron injec-
tions is to monitor haemoglobin levels in the blood
ofthe young piglets. The levels should be higher
than 8 ml/I OOml. Iron injections should be admin-
istered in the neck rather than the ham to avoid
staining of the most valuable cut in the pig carcass.
168

187. undergo at weaning. Pigs accustomed to drinking
from a watering system prior to weaning will
experience fewer problems with water intake after
weaning. Make the water source easy for newborn
piglets to find. Piglets take too long to find and use
a nipple drinker so a dish drinker located in the
creep area is a better choice, at least until the piglets
are accustomed to consuming water. If water
nipples are to be used, then these should be pointed
downward to discourage piglets from playing with
the nipple and wasting water.
Use of Milk Replacers
Milk replacers have been used quite successfully
to raise orphan piglets or surplus piglets from large
litters. Milk replacer may also be offered to piglets
while they are with the sow in the farrowing crate to
increase weaning weights and reduce variation in
weaning weight in early weaning programs
(weaning age 21 days or less). A point to
remember: ifmilk replacers are used, piglets must
still obtain colostrum from the sow or another
source, such as cow colostrum.
Artificially reared piglets should be fed milk
replacer frequently (4 to 6 times daily) and in small
doses ( 10 ml of milk replacer per pig at first).
Daily consumption of milk replacer may be
gradually increased to 300 to 400 ml per piglet at
which time dry feed should be introduced. Prevent
over-consumption of milk replacer and take care to
ensure the piglets do not get wet during feeding.
The successful use ofmilk replacers to reduce
pre-weaning mortality in runt pigs has prompted the
development ofseveral mechanical devices or
"artificial sows" which are designed to automate the
delivery ofmilk replacers. The manufacturers of
these devices claim that a piglet can be fostered
onto an artificial sow as early as 3 days ofage.
The need and use ofmilk replacers in the
commercial swine industry is anticipated to
decrease as more complex creep and early weaning
feeds are developed. Some ofthe early weaning
dry feeds can support good levels ofperformance in
piglets weaned at 7 days or earlier (see chapter 8).
Photo 7-3a.
l)�
Creep Feeding
The sow generally reaches her maximum milk
production during the third week oflactation;
thereafter, milk production dec1ines steadily.
Because ofher reduced milk production, the sow is
unable to supply sufficient nutrients to meet the
steadily increasing demands from growing piglets.
Ifthe young pigs' rapid growth rate is to be
maximized, the gap between their nutrient
requirements and the nutrients supplied by the saw's
milk must be fiJled by means ofcreep feeding.
82 4 6
Week of Lactation
O+---,.�.---.---.�...-������---��
0
8
"ti
...
>
�2
aJ
0
Photo 7-3b.
Piglets should have ready access to water.
Photo courtesy: Centre for Food and Animal Research. Ottawa. Figure 7-1. A lactation Curve for a SO..
- -
169

188. t 2 3 4 5 6 7
AGE (WffkS)
La-(·-L-......,..-.....-�..----...-----.--, ...,,....ug,u,
Figure 7-2. Digestive Enzyme Activity Pattern in
Young Swine.
a
> 7
.... 6
> .,,,
fi 5 �......
< 4
w
� '� 2
w
During the first two or three weeks of life, up to
approximately five kilograms body weight, a
piglet's digestive enzymes necessary for the diges-
tion ofstarch, sugar (sucrose), and non-milk pro-
teins are present at relatively low levels. A piglet's
digestive tract is best suited to digest milk proteins
(casein), milk sugar (lactose), glucose, and specific
fats so its diet should include ingredients such as
skim milk. high quality whey products, high quality
blood products, added fat (preferably fats with
medium chain fatty acids, such as coconut oil, or
unsaturated fats, such as com oil, canola oil, or soy
oil), cooked cereals (rolled oats or flaked corn), and
glucose. In addition, small amounts ofnon-milk
proteins should be added to encourage development
ofthe piglet's digestive enzymes. High quality pre-
starter (Phase T or MEW) diets may be used as
creep feeds for suckling piglets weighing less than
five kilograms (see chapter 8).
quality diet. Such a diet would contain at least
l.25% (up to 1.70%) lysine and 3400 - 3600 kcal
DE/kg. This was demonstrated by recent studies
conducted at the Agriculture Canada research
station in Ottawa. In these studies, piglets were
weaned at four weeks ofage. Litters on high
complexity, palatable diets ate more creep feed
prior to weaning, tended to gain more during the
week before weaning, and converted feed more
efficiently. These piglets also gained more weight
in the first two weeks after weaning as compared to
litters that were fed a low-complexity, corn-soybean
meal based diet.
Benefits of Creep Feeding
The benefits derived from creep feeding have
been amply demonstrated. The most significant
benefit is that piglets are heavier at weaning. In a
typical four week weaning program, weaning
weights may be as much as I 0% higher if high
quality creep feeds are used. For piglets weaned at
an earlier age, the intake ofcreep feed is generally
insufficient to stimulate heavier weaning weights.
Tn addition, the variation in weaning weights
within a litter may be smaller, i.e., fewer runt pigs in
the litters at weaning. The response to creep feed
will also depend on litter size, the individual sow's
milking ability and the quality of creep feed.
Creep feeding has also been shown to be
beneficial to the sow. When creep feed is provided
piglets tend to suckle less intensively so sows tend
to be in better body condition at weaning. As a
result, these sows have shorter weaning to
rebreeding intervals and higher conception rates
than sows whose litters have not been provided with
creep feed.
Creep Feed Formulation
Creep feeds are designed to supplement the
nutrients contained in sows milk. Therefore, creep
feed does not have to provide all the nutrients
required by the suckling pig. Digestibility and
palatability arc far more important factors in evalu-
ating creep feeds than nutrient content. However,
the suckling pig should still be supplied with a high
Creep feeding can also minimize the setback that
piglets undergo immediately following weaning.
An abrupt change from a liquid diet to a meal diet is
a nutritional stress that generally results in a growth
check during which time pigs consume very little
feed, gain little weight, and often suffer from
scours. A gradual introduction to solid feed during
the suckling period will develop the enzymes
required for digestion, allow piglets to learn how to
consume dry feed, and minimize the growth check.
However, in order to achieve a reduction in setback
after weaning through enhanced creep feed con-
surnption, substantial amounts ofcreep feed must
be consumed. According to some studies, this may
be as much as one kilogram per piglet.
170

189. At approximately three weeks ofage, or when
body weight exceeds five kilograms, this largely
milk-based diet can be replaced by a less expensive,
pre-starter diet based on cereals and high quality
proteins. In general, high energy grains such as
corn or wheat as well as readily digested protein
supplements such as soybean meal form the basis of
most pre-starter diets. The pre-starter diet should
still contain some of the high quality products that
are included in creep feeds. Ingredients such as oat
groats, flaked corn. fish meal. dried skim milk,
dried whey, sugar, and fat are commonly added to
increase palatability and digestibility. Pre-starter
(Phase I or high quality Phase II) diets may be used
as creep feeds for suckling pigs weighing more than
five kilograms as well (see chapter 8).
Factors Affecting Creep Feed Intake
Creep feed consumption is affected by many
factors. These factors include: the feeding system,
feed palatability, the environment in which the
piglet is housed the sow's milk composition and
yield, the piglets' health, vigor, and growth rate, and
the amount of water available. A reasonable target
creep feed intake for litters weaned at 4 weeks is
about 2.5 kg offeed per litter. If litters are not
achieving this level ofintake, take steps to increase
their creep feed consumption.
Creep fed piglets are heavier at weaning ifweaning age is
28 days or greater.
One ofthe most important factors stimulating
piglets to eat creep feed is the feed's freshness. All
too often feed is placed in a creep feeder and left
there to be fouled, attract flies, and become stale
before being cleaned and/or replaced. Little and
often is the rule for creep feeding, with fresh creep
feed supplied each day. Not only does this practice
ensure the creep is always fresh, but the daily arrival
of fresh feed serves to stimulate the piglets' inherent
curiosity in the new material, which also helps to
encourage consumption.
Consumption can be stimulated by feeding a
pelleted or crumbled creep feed. Piglets fed pellets
with a small diameter (0.4cm or smaller) or crum-
bles tend to eat more and waste less as compared to
piglets fed pellets with a large diameter (0.5cm or
larger). Ifsmall pellets or crumbles are not avail-
able, a short-cut pellet (2 - 3 mm long) is preferred.
Even though piglets have access to the sow's
milk while eating creep feed, they must have access
to fresh water if feed intake is to be maximized. If
pigs are weaned after three to four weeks ofage,
creep feed intake will be reduced significantly
without readily available fresh water. Pigs accus-
tomed to drinking from a nipple waterer while in
the farrowing crate will experience fewer problems
in adapting to the watering system at weaning.
However, water nipples should be pointed down-
ward to discourage piglets from playing with the
nipple and wasting water.
Research has shown that the location ofthe
creep feeder in the pen does not affect feed intake
or feed wastage. However, raising the creep feeder
four inches from the floor has been shown to result
in a significant reduction in creep feed wastage.
Since creep feeds are relatively expensive, this
simple procedure is certainly cost-effective.
Creep feed composition will affect how much
piglets eat. As mentioned previously, ingredients
such as oat groats, flaked corn, fish meal, dried
skim milk, dried whey, sugar, and animal fat have
been utilized to increase creep feed palatability.
Many flavor-enhancers are currently being
promoted as a means of increasing creep feed
consumption, but research on the effectiveness of
these artificial flavors is inconclusive so their use
remains questionable.
171

190. Starting Pigs on Creep Feed
Piglets should be started on creep feed when
they are about 7 days old by offering a little feed on
a clean, dry section of the floor (use a board in
farrowing crates with a slatted floor). Piglets are
more likely to show interest in feed initially offered
in this manner. Never offer creep feed within a
couple ofhours of the sow being fed; the litter will
be suckling or sleeping and may not notice the feed.
ln addition, never offer more than 20 g/litter/day
until the piglets are obviously consuming the feed.
Floor feeding should continue for the first three
to four days or until the piglets are definitely eating
the feed. When the litter is obviously eating the
feed, a small feeder may be used. Since piglets
prefer to feed together, the feed trough should be
large enough to allow as many piglets as possible to
feed at the same time. A fairly heavy, shallow,
circular trough is suitable for this purpose because it
makes the creep feed obvious and easily accessible
to the piglets, as well as accommodating a fairly
large litter.
Creep feeding should be introduced by placing a small
amount of a good quaI ity feed on the floor of the crate.
Creep Feed Induced Hypersensitivity
Creep feed made up of large quantities of certain
ingredients, such as soybean meal and legume
seeds, may contain some anti-nutritional elements.
Exposing piglets to large quantities of these ingredi-
ents may provide dietary antigens which can de-
velop a transient hypersensitivity in the young
piglet's gut. After seven to ten days the
hypersensitivity normally disappears, but in some
cases, the hypersensitivity can result in an immune
response in the gut, damaging the intestinal tract
lining The damage can cause diarrhea in the newly
weaned pig, and poor post-weaning performance,
However, ifcreep feed is introduced early and large
amounts are consumed prior to weaning, the im-
mune system may develop a tolerance to feed
antigens prior to weaning, and post-weaning scour-
ing can be controlled. The effect offeeding strate-
gies on changes in the piglet's immune system and
hypersensitivity in the gut remains an active area of
research.
Additional Reading and References
Aherne, F.X., Danielsen, V. and Nielson, H.E.,
I 982. The effects ofcreep feeding on pre and post
weaning pig performance. Acta Agric. Scand. 32:
155-160.
Azain, M.J., and Jewell, D.E. 1991. Impact of early
nutrition on pig performance. Proc. 1991 Georgia
Nutrition conference. pp 99-107.
Etheridge, R.D. and Seerley. R.W., 1984. Aspects
of dietary stresses on the digestive system ofthe
baby piglet. Proc. 1984 Georgia Nutrition Confer-
ence. pp 32-43.
Fowler. V.R., 1980. The nutrition of the piglet.
Proc. Nottingham Nutrition Conference for Feed
Manufacturers. pp. 1-20.
Fraser, D., J.J.R. Feddes and E.A. Pajor. 1994.
The relationship between creep feeding behaviour
of piglets and adaptation to weaning: Effect of diet
quality. Can. J. Anim. Sci. 74: l-6.
Groskreutz, K.A., 1983. Successful rearing starts
with good colostrum. Pigs 2: 3-6.
Veum, T.L. Feeding neonatal pigs. In: Swine Nutri-
tion (Ed. E.R. Miller, D.E. Ullrey and A.J. Lewis)
pp 483-496.
172

191. 8. FEEDING THE WEANED PIG
Figure 8-1.
Adapted from Tokach et aJ. 1992. Proc. Kansas State
Univ. Swine Day. Manhattan, KS. pp. 15-17.
Healthy, vigorous pigs that are eating and growing
well adjust more easily to weaning and suffer little
or no effects of "post-weaning lag." Poor-doing,
lethargic pigs are slower-growing, do not adjust
well to weaning and suffer the greatest drop in
performance at weaning. Clearly, the key is to get
pigs offto a good start to ensure ongoing success
(Figure 8-1).
In addition, it is almost impossible to prevent
some decline in nutrient intake as the pig changes
from sow's milk to a starter diet. This decline in
intake results in a proportionate decline in meta-
bolic body heat generation, making the pig more
susceptible to chilling at the time ofweaning.
Control ofthe thermal environment is critical, and
in some respects, will be related to diet composition
(see "the pig's environment" later in this chapter).
It is self-evident that exposure to disease-causing
organisms compromises the ability of the pig to
adjust to weaning. However, management, as
opposed to treatment of disease, has proven to be
the most effective strategy. Attaining minimum
disease status in a herd offers many overall advan-
tages. particularly for the weanling pig. However,
not all diseases can be eliminated from the herd.
Depending on the diseases that are a concern in a
given herd, segregated early weaning (SEW) offers
advantages in terms ofreducing pathogen transmis-
sion from the sow to her litter (Table 8-1 ). In the
instance ofother diseases, minimizing the age
spread ofpiglets within the farrowing room and
within the nursery is highly desirable.
In addition to the stresses ofnutrition and disease,
the impact ofa sub-optimal environment and
disturbances to the previous social order must not
be underestimated. A holistic approach to
managing the newly-weaned pig, particularly as the
industry moves to weaning at an earlier age,
becomes paramount. Modification of diet cannot
overcome the effects ofa poor environment, just as
creating an ideal environment will not compensate
for a poor diet. All the pieces ofthe puzzle must
be in place and integrated.
However. the process of weaning, no matter how
carefully managed, results in changes in the gut of
the pig that make it more susceptible to digestive
upset, diarrhea and impaired appetite. The objec-
tive, then, in developing diets for the weanling pig
is to recognize these unique needs and facilitate a
smooth transition to the piglet's new lifestyle,
>225150 • 2250· 150
A.D.G. (grams) DURING FIRST WEEK AFTER WEANING
168
166
184
182
180
s 178
a:
� 176
f? 174
(I)
� 172
0
The period immediately after weaning is an
extremely important time in the life of the pig, one
which has a significant impact on future perform-
ance. For example, on farrow-to-finish farms
where age at market weight has been identified as a
problem, one often finds the root cause in the
nursery, rather than in the growout barn. Indeed,
studies at the Prairie Swine Centre have demon-
strated that about 30% of the variation in age to
market can be attributed to the time it takes a pig to
reach a body weight of23 kg.
170
Stresses at Weaning
At the time of weaning, the pig is exposed to a
series of stressors that, if left unchecked, can lead to
poor performance and increased mortality. For
example, due to removal from the sow, the piglet is
forced to change from an almost ideal liquid diet,
based on lactose, fat and milk protein, to a dry diet
based on different proteins, fats and carbohydrates.
Sow's milk offers other advantages, containing
'non-nutritive' components that facilitate digestion
and provide protection against disease.
173

192. Source: Sheridan, 1995.
Table 8-1. Recommended Weaning Age for
Disease Elimination.
NB. Strep. suis, Haemophilus parasuis, Actinobacillus.
suis are not easily eliminated.
Photo 8-1.
Failure to achieve these performance targets could
be due to diet composition, but could also include
such factors as housing (all-in-all-out is essential),
environment (warm, dry and draft-free), genetics
and health.
Water medicators are often used to mix nutritional
supplements or medication into water supplies.
10
10
21
21
21
21
Age (days)Infectious Agent
Mycoplasma hyopneumonia
Actinobacillus pleuropneumonia
T.G.E. virus
Serpulina hyodysenteriae
PRRS
resulting in rapid and efficient growth and Limited
health problems. This must all be accomplished
with a keen eye to cost and economic efficiency.
Pasteurella multocida
Performance Targets
Monitoring performance is essential for success;
however, performance data is only useful if it is
employed by management in a constructive way.
One effective approach is to compare one's per-
formance with that being achieved by other similar
units, in order to determine where further improve-
ments might be sought. Ifsuch information is not
available from neighbouring farms, the targets
illustrated in Figure 8-2 and Table 8-2 may be used.
"Good" represents the level ofperformance ex-
pected in a reasonably good environment, while
"better" illustrates what might be expected with a
very high level of overall management. "Best"
represents a level ofperformance which currently
exceeds that achieved on most farms, but which
should become more readily achieved as our under-
standing ofweanling management grows and
related technology improves.
Maximizing Feed Intake
In most circumstances, weanling performance is
Limited by feed intake, and more precisely, by
energy intake. Producers who achieve a high level
of feed intake are able to realize the best overall
performance in their nursery. A few key points
appear to be crucial to such success.
Feed intake is heavily influenced by diet digest-
ibility. Seemingly small reductions in digestibility
can have a proportionately large impact by reducing
voluntary feed intake.
Fresh water must be readily available. Piglets
sometimes have difficulty finding nipple drinkers
immediately after weaning, so attention to early
water consumption is important. Dish-type drinkers
offer advantages in terms ofpigs accessing water
soon after weaning, but difficulties in keeping them
clean reduces their popularity.
Table 8-2. Performance Targets for Pigs from 7 to 25
kg Body Weight.
Average daily gain (kg)
Average daily feed (kg)
Feed conversion
Mortality,%
Good
460
740
1.6
1.0
Better
520
780
1.5
0.5
Best
585
820
1.4
0.2
Water containing high levels ofminerals,
especially sulphate, can contribute to diarrhea, but
have surprisingly little impact on feed intake. Each
situation where water is a concern needs to be
evaluated closely.
Much is often said about the importance of fresh
feed. While caked, stale or fouled feed is clearly
174

193. Q
0
g� <c
... C)
...
·--c
as
�
"' l'I
I
�
z
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z�o
�;s l
...........CZ)�c, .....
�
........
--z ---.....------·u,
-·
.........
II:I
<.O
LO
CI
'<t
LO
er:>
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�
"O
-w
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CI
0
<X) <.O '<t CI O <X) <.O '<t
CI CI CI CI CI
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(sweJ50l!)f) .lH813M
Figure 8-2. Growth Curves for Pigs Demonstrating Good, Better and Best Perfromance to 1 O Weeks ofAge.
175

194. undesirable, there is little data to suggest that feed
needs to be added fresh daily. Indeed, limited research
suggests barn odours have little effect on voluntary
feed intake in weanling pigs. However, regularly
adding new feed to the feeder appears to attract the
pig's attention and thus may stimulate intake.
Under some circumstances, limiting daily feed
intake in the newly-weaned pig might help to
control diarrhea. While such a practice may be
effective as a short-term solution, ultimately the
underlying cause ofthe problem needs to be
addressed, as the objective in the nursery is to get
pigs onto full-feed as quickly as possible. Only
then will growth rate be maximized. A full
discussion of limit feeding appears later in this
chapter.
Table 8-3. Nutrient Requirements of the Weanling Pig.
Other important factors that determine feed intake
are addressed later in this chapter. These include
ambient temperature, floor space and feeder design.
Managing the Early-Weaned Pig
Although feed composition is critical to success in
early weaning (<21 days), proper animal and feed
management is also essential. Pigs should be
weaned in groups of 10 - 15 pigs per pen into an
all-in-all-out nursery. At the time ofweaning, the
temperature should be approximately 32° C. Heat
lamps should also be used for the first two or three
days, especially for smaller pigs. Ifheat lamps are
not available, the temperature should be increased
by 2° C. The temperature can be reduced by 1 ° C
every two to three days until the room temperature
is 28° C. At this time, the temperature should be
Nutrients
Wean to 7 kg
Weight Range, kg
7 to 12 kg 12 to 20 kg
Energy!
D.E. kcal/kg 3450 - 3600 3450 - 3550 3350 - 3450
Available amino acids2
Lysine, g!Mcal DE
Lysine,%
Methionine, %
TS.A.A.,%
Threonine,%
Tryptophan, %
Leucine, %
lsoleucine, %
Valine,%
Phenylalanine,%
Histidine, %
Arginine,%
Minerals3
Calcium,%
Phosphorus, %
Sodium,%
Chloride,%
3.60 3.10 2.90
1.30 1.10 1.00
0.36 0.31 0.28
0.72 0.61 0.56
0.85 0.72 0.65
0.22 0.19 0.18
1.30 1.10 1.00
0.78 0.66 0.60
0.88 0.75 0.68
0.74 0.63 0.57
0.42 0.35 0.32
0.55 0.46 0.42
0.90 0.80 (1.00) 0.70 (1.00)
0.70 0.65 (0.80) 0.60 (0.80)
0.12 0.12 0.12
0.15 0.15 0.15
1
Not a "requirement" per se, but a suggested D.E. level for pigs ofthis weight (age) range. Actual D.E. will depend on
available ingredients and relative cost.
2
All amino acid requirements expressed as "available" using ilea! digestibility as the standard.
3Lcvels for animals destined for slaughter. Levels for animals intended for breeding stock are provided in parenthesis.
176

195. lowered by 1° C each week. These are estimates
only, as conditions due to drafts, building insula-
tion, flooring material, humidity, etc., will affect the
exact needs of the pig. Pig behaviour is a good
indicator of comfort. Lying in piles on their bellies
is generally an indication ofchilling. Panting is
indicative of heat stress. Ideally, pigs should be
lying on their sides, well separated from their
neighbours. Remember, high temperatures suppress
feed intake and may contribute to illness.
Initially, feed should be provided on pans placed
in the centre ofthe pen. Heavy metal pans with 12
to 25 millimetre edges are desirable as they are easy
to work with, difficult to tip, and help reduce
wastage. Various feeding regimes are recom-
mended, but we like offering 50 - 75 g per pig on
the pan. It should be replenished three times a day.
By the third day, pigs should be starting to use the
self-feeder. By the third to fifth day, the feed pan
can be removed.
Feeders should be adjusted to ensure ready access
to feed while avoiding wastage. Plenty offeeder
space is required, as pigs at this age are group
eaters. Single space feeders are not recommended.
To avoid fouling, the feeders should be at least 15
cm from a corner, since pigs Like to defecate in
corners. Finally, feeders should be designed with
spacers in the trough to prevent pigs from sleeping
in them.
While nipple drinkers are easiest to keep clean,
dish drinkers are more conducive to water intake at
the time ofweaning. Most importantly, water must
be readily available at all times.
Photo 8-2.
Some people recommend minimum lighting to
reduce tail biting and other vices. This may actually
have the opposite effect. Turning on the lights to
check the pigs then creates a high level ofactivity
that in some cases has led to increased vices. It is
best to create a pleasant, warm, dry, draft-free, and
uncrowded environment for the pigs. These
conditions are the best way to avoid behavioural
problems.
Nutrient Requirements of the Weaned
Pig
The nutrient requirements ofthe weaned pig, like
other classes ofswine, depend on many factors,
including their genetic potential for lean and fat
gain, the environment and health status. For the
purposes ofthis chapter, when defining nutrient
requirements and diet composition, we assume
superior genetics, an optimurn environment and a
reasonably high health status. There are three
reasons for taking this approach.
First, our understanding ofthe interrelationship
among health status, the environment and nutrient
requirements is not well understood at this time.
Because ofthe importance ofperformance at this
stage in production, one will typically err on the
side of over- as opposed to under-formulation.
Second, the economic "risk" ofover-feeding
nutrients in the nursery is small compared to the
potential benefit ofimproved performance. This is
due to the fact that pigs in the nursery eat a rela-
tively small amount offeed; indeed, Jess than lO
percent of the total feed required to carry the pig
from weaning to market will be consumed during
this period. In particular, during the early post-
weaning stage, diet cost will be influenced more by
selection of ingredients than levels of nutrients.
This will be discussed in the next section.
Phase feeding programs help to address this
problem as well, as they allow producers to meet
the unique needs of the pig as it progresses from 2
or 3 weeks ofage through to 8 to lO weeks of age
in the most economical fashion. The younger pig
has much more stringent requirements, but in early-
weaning systems (<10 days), less than 15% ofthe
total starter intake occurs prior to 7 kg body weight
177

196. (Figure 8-3). In pigs weaned at 19 days ofage, less
than 5% ofthe total starter feed is consumed prior
to 7 kg body weight.
18.0 to 23.0 kg
30%
Figure 8-3a. Starter Feed Usage: two week weaning.
18.0 to 23.0
kg
34%
5.5 to 7.0 kg
5%
7.0 to 11.5 kg
22%
39%
Figure 8-3b. Starter Feed Usage: three week weaning.
Third, during the weanling period, daily nutrient
intake is generally the most critical factor limiting
animal performance. While genetics. as well as the
environment and health may influence feed intake,
few pigs are fed diets that allow full expression of
genetic potential because the nutrient density ofthe
diet is limiting for both practical and economic
reasons (Figure 8-4).
Common
Dietary D.E.
Range
DIET D.E. CONCENTRATION
Figure 8-4. Relationship Between Dietary Energy
Concentration and Body Protein Gain in Weanling
Pigs. Adapted form Campbell and Dunkin, 1983.
Recommended nutrient requirements for the
weanling pig are summarized in Table 8-3. The
recommended energy levels are expressed as a
range and are quite arbitrary. The exact levels will
depend on the cost and availability ofhigh energy
basal feedstuffs. The ability to include moderate
amounts of fat into diets based on wheat must also
be considered. Lower energy values are possible in
all cases, although growth rate will decline propor-
tionately.
No lower limit for crude protein is provided.
Diets are formulated to meet amino acid require-
ments. Under commercial conditions, ifthe re-
quirements for essential amino acids are met, then it
is assumed that the need for non-essential amino
acids will also be addressed. The one exception
that nutritionists might consider is glutamine.
There may, however, be an upper limit to crude
protein in these diets, but that has not been firmly
established. There are concerns that ifcrude protein
levels are too high. scouring may be encouraged. In
addition, the metabolic cost ofeliminating excess
nitrogen should be minimized, allowing available
nutrients to be directed towards more productive
purposes.
Feeding Programs
For a variety ofreasons, including a rapidly
maturing gastrointestinal tract and the cost of
providing an effective diet to the newly-weaned
piglet, the optimum diet for weanling pigs changes
almost weekly. Consequently, a phase feeding
program is necessary to balance animal perform-
ance and feed costs. The nature ofthe program will
depend on a variety of factors. the most important
ofwhich is the age at weaning.
Transient Gastrointestinal Hypersensitivity
Research over the past two decades has revealed
that early-weaned pigs experience a transient
allergic reaction to certain dietary proteins. Certain
vegetable proteins, such as those found in soybean
meal, have been identified as contributing to
transient allergic reactions. Young piglets, once
exposed to soybean meal, produce antibodies
specific to soy protein antigens; such exposure can
178
3.4 to 7.0 kg
13%

197. result from offering small amounts ofcreep feed
containing soybean meal, or from piglets eating
small quantities of the sow's feed. This allergic
response results in damage to the intestinal villi,
which in tum impairs digestive and absorptive
capacity ofthe associated epithelial cells. Over
time, pigs develop a tolerance.
The problem is less acute in pigs weaned at four
weeks ofage or later, due to the larger intake of
creep feeds and the resulting tolerance to soybean
proteins that develops. It is more acute in younger
pigs because their consumption ofcreep diets wiU
be Jess and tolerance will not yet be established.
A variety ofproducts derived from soybean meal,
such as soy protein isolates or concentrates, have
been developed to overcome this problem. In
addition, based on research from Kansas State
University, various kinds ofheat treatment, includ-
ing moist extrusion, help to alleviate the problem.
Simple Versus Complex
An age old topic ofdiscussion in nursery diets
revolves around the use ofcomplex versus simple
diets. Complex diets involve a number ofdifferent
ingredients, including cereal grains, proteins from
both animal and vegetable sources as well as fats
and/or oils. Simple diets, in contrast. generally
contain cereal grains, vegetable proteins and a small
quantity of oil. In reality, a continuum exists from
highly complex diets, with a dozen or more ingredi-
ents, to a very simple diet containing no more than
4 or 5 ingredients. Complex diets are more expen-
sive to manufacture and require more skill in
obtaining the large number of ingredients. They
also tend to be more difficult to manufacture and
often are difficult to peUet. However, one cannot
dispute the much improved performance observed
with early-weaned pigs fed such diets as compared
to the more simple formulations.
The discussion arises from the relative economics
of the two types ofdiets, and in particular, whether
early improvements in performance are reflected in
overall gains in productivity and profitability for the
farm. The answer, as one might suspect, is not a
simple one. Some proponents ofsimple diets
suggest that compensatory gain later in the
production cycle make up for early losses in animal
performance. The presence or absence of true
compensatory gain in pork production remains
controversial.
It is generally safe to conclude that in production
systems requiring rapid animal throughput or in
early weaning systems, complex diets are essential.
It is difficult to envisage getting pigs to market in
less than 150 days on simple starter diets, or
weaning 12 to 17 day old pigs onto a cereal-based
feed. Conversely, with older weaning and less
emphasis on days to market, less expensive diets
may suffice. To restate, phase feeding allows
producers to optimize their feeding programs, using
more complex diets at the time of weaning,
followed by increasingly simple and less expensive
diets later.
The solution, as in other controversies, remains
the same: producers should monitor performance on
their farm, consider all options and determine the
best choice under their particular circumstances.
The final decision will depend on economics and
animal well-being. Without information specific to
their farm, producers must depend on
recommendations based on "typical" or "average"
results.
Ad libitum Versus Restricted Feed Supply
Diarrhea is an all-too-common problem in many
nurseries. Diet change, environmental stress and
reduced resistance to disease combine to increase
the likelihood of illness, often related to the
digestive system. Typically, at the time ofweaning,
a period of low feed intake is followed by gorging
which overloads the intestinal tract, resulting in
scouring.
One effective way to address this situation is to
limit feed the pigs for the first 5 to 7 days after
weaning to prevent this period ofoverconsumption.
While the practice is effective, it is also labour
intensive and requires careful management to ensure
that feed intake is not restricted excessively,
resulting in slower growth. Consequently,
producers seek ways to provide diets ad libitum that
avoid diarrhea and thus eliminate the need to restrict
feed intake.
179

198. The solution is to provide a high quality physical
environment which includes good control of
temperature and embraces the all-in-all-out
management system. These two factors, along with
minimizing drafts and keeping piglets dry, will go a
long way towards eliminating most of the major
contributors to ill health.
The other solution is diet composition. The very
high quality diets recommended for the newly-
weaned pig are designed to be highly palatable and
digestible thus avoiding the scenario that leads to
gut overload. Such diets are costly, but support
maximal performance. It is up to each producer to
decide whether a lower cost diet, limit-fed for the
first five to seven days after weaning, is preferable
in their operation.
Diet Form
There is not a great deal of published information
on the relative merits ofpellets, crumbles and mash
in starter diets. Generally speaking, large pellets
should be avoided in the very young pig as it does
reduce feed intake. For creep feeds and early-phase
starters, crumbles, small pellets or short-cut pellets
are generally preferred. Further discussion on
pelleting pig diets appears in chapter 10.
Phase Feeding Programs
Whether one is considering the breeding herd,
market hogs or weanling pigs, phase feeding
programs are employed to closely match an
animal's changing requirements with diet
composition in the most economical manner. In the
case of the weanling pig, these changes are rapid
and profound. This is due not only to nutrient
requirements changing, but also the ingredients
most suited to the two to three week old piglet
differ in a significant fashion from those necessary
in the five week or eight week old pig.
The newly-weaned pig, especially those weaned
at less than 4 weeks ofage, have a unique
requirement for a diet ofhigh nutrient density, high
digestibility and high palatability. Meeting these
needs requires very expensive ingredients.
However, as the pig ages, its needs become less
stringent and a broader array of ingredients will
support optimal performance.
Diet Composition
While meeting the nutrient requirements ofthe
weanling pig is essential in providing a balanced
diet, the composition of the diet, in terms of
ingredient content, is also very important. This is
due to the fact that the gastrointestinal tract ofthe
young pig is not fully matured and is influenced by
the presence ofanti-nutritive factors more so than in
older animals. It is also assumed, at least, that
palatability is more important at this stage of
production.
The primary focus of composition ofweanling
diets is providing nutrients in a package that
recognizes the unique needs ofthe immature
gastrointestinal tract, avoids anti-nutritive factors
and maximizes early feed intake. Cost is an
important consideration, but needs to be addressed
in the context ofthe total production system.
Generally speaking, diets for the newly-weaned pig,
especially those weaned at less than 4 weeks ofage,
represent a compromise between what is ideal, from
the pig's perspective, and what is economically
feasible, from the producer's perspective. The
greatest success occurs when this compromise is
managed most effectively.
While ingredients can be selected based on
"typical" results, it is important to realize that
quality standards are particularly important in
weanling diets. Following are a few guidelines to
consider.
Fats and Oils
Young pigs, particularly those immediately after
weaning are sensitive to the type offats used.
Short-chained fatty acids are more digestible than
medium-chained fatty acids and long-chained fatty
acids are the least digestible. The differences are
greatest in the 3 week old piglet and decline almost
weekly thereafter. As the pig ages, its ability to
utilize the energy from fats increases. During the
first 2 to 3 weeks after weaning, vegetable oils are
clearly preferred over tallow and lard. However, as
the pig ages, animal source fats are used with
increasing effectiveness.
180

199. To maximize the utilization ofenergy from fats,
excess calcium should be avoided to reduce the
formation of poorly digested soaps. For this
reason, calcium levels must be carefully controlled
in starter diets.
Blood Products
Only spray-dried blood products should be used
in the diet ofthe young pig; flash and ring dried
blood products are of lesser nutritive value and
should generally be avoided in starter cLiets.
Spray-dried blood meal is collected from packing
plants. The moisture is removed in a very
controlled manner to prevent damage to the
proteins. Spray-dried plasma proteins and spray-
dried blood cells are produced in a similar manner.
The whole blood is treated with an anticoagulant to
maintain it in liquid form. It is then centrifuged to
separate the cells from the plasma. Once separated,
the cells are spray-dried in a manner similar to that
applied to whole blood. With increased interest in
plasma proteins and blood cells, blood meal is
becoming a less common ingredient.
The manufacture ofthese products has
contributed greatly to the success ofearly-weaning
programs. However, when formulating diets
containing blood products, particular attention must
be directed to methionine levels, as these tend to be
quite low. For example, in whole blood, the ratio of
methionine to lysine is about 0.12, less than half of
what is required in the final pig diet.
Table 8-4. Diet Composition Guidelines for the Weanling Pig.
Ingredient Body Wei�ht Range. kg
Phase I Phase II Phase Ill
Very early wean Early wean Late wean
{<15 days)' (<21 days)' (21 to 28 days)' 7 - 12 kg 12- 20 kg
Soybean meal, max. 15% 20% 25% 25% NUL
Porcine plasma protein.min. 6to 10% 5to 7% Oto3% Oto 5% nil
Spray-dried blood meal, max. Oto 1.5% I to2% Oto4% Oto 5% Oto 5%
Whey powder, min. 20 to 25% 20 to 25% 20 to25% Oto 15% Oto5%
Lactose, min. 20% 15% 9% 0% 0%
Growthpromotant Yes Yes Yes Yes Yes
Form Crumble or small pellet Crumble/short pellet or
pellet mash
I
Feed until the pigs reach 7 kg bodyweight; for later weaning. feed for at least 7 days after weaning
NUL - no upper limit
NB. When ranges are provided, consideration can be given to economic conditions as well as the level ofstress imposed on the
animal by housing conditions.
Whey and Skim Milk Powder
Whey powder is used extensively in weanling
diets, especially immediately after weaning when
lactose and milk proteins are preferred over starch
and vegetable proteins. However, for greatest
success, high quality whey powder must be used.
For early-weaned pigs at least, spray-dried, edible-
grade, high-lactose whey is preferred, even though
it is more expensive.
Skim milk powder may also be used; however, it
tends to be a much more expensive source of
lactose and casein. Ifskim milk powder is priced
competitively, it is a highly desirable product in
starter diets.
Dehulled Cereal Grains
Oat groats, when available, tend to be a highly
palatable ingredient for use in starter diets. In
regions where other cereal grains are more common
181

200. Table 8-5. Sample Diets for Weanling Pigs.
Body Weight Range. kg
Phase I Phase II Phase III
Very early wean Early wean Later wean
(<15 days) (<21 days) (21 to 28 days) 7 - 12 kg 12 - 20 kg
Ingredients
Wheat 37.55 39.39 40.73 51.68 69.37
Com 36.69 39.01 41.37 52.52 66.38
Soybean meal - 47% 15.00 15.00 20.00 20.00 25.00 25.00 25.00 25.00 28.65 25.00
Spray dried whey 25.00 25.00 20.00 20.00 25.00 25.00 15.00 15.00
Lactose 5.00 5.00 5.00 5.00
Select menhaden fish meal 2.50 2.50
Spray-dried plasma proteins 6.00 6.00 5.00 5.00 2.50 2.50
Spray-dried blood meal 2.00 2.00 2.50 2.50 1.25 l.25 2.50 2.50
L-lysine HCI 0.21 0.15 0.11 0.03 0.10 0.04 0.08 0.12 0.13
L-threonine 0.14 0.11 0.11 0.08 0.13 0.10 0.08 0.04 0.10 0.10
DL-methionine 0.16 0.09 0.17 0.10 0.15 0.08 0.07 0.03
Fat/oil 3.80 3.60 4.10 3.90 1.00 l.80 1.00 2.00 0.50 l.15
Premix 3.50 3.50 4.00 4.00 3.50 3.50 3.75 3.75 4.25 4.25
Antibiotic + -r + + + + + + +
Nutrients. minimum
D.E., kcal/kg 3600 3550 3600 3550 3450 3450 3450 3450 3400 3400
Crude protein, % 22. l 23.9 22.0 23.8 22.2 24.1 20.7 23.l 19.5 21.5
Lysine:D.E., g(Mcal 3.60 3.60 3.60 3.60 3.60 3.60 3.20 3.20 2.90 2.90
Dig. lysine,% l.30 1.28 1.30 1.28 1.24 1.24 1.10 l.10 0.98 0.98
Dig. methionine,% 0.36 0.36 0.36 0.36 0.36 0.36 0.31 0.31 0.28 0.28
Dig. TS.A.A., % 0.72 0.72 0.72 0.72 0.72 0.72 0.61 0.61 0.55 0.55
Dig. threonine, % 0.85 0.85 0.85 0.85 0.85 0.85 0.72 0.72 0.65 0.65
Dig. tryptophan, % 0.22 0.22 0.22 0.22 0.22 0.22 0.19 0.19 0.17 0.17
Calcium,% 0.90 0.90 0.90 0.90 0.90 0.90 0.80 0.80 0.70 0.70
Phosphorus, % 0.70 0.70 0.70 0.70 0.70 0.70 0.65 0.65 0.60 0.60
NB. These are example diets only and should not be employed without consulting a professional nutritionist. Exact
formulations will require integration ofthe nutrient profiles oflocal ingredients, as well as completion ofleast cost
procedures. Also. the technology associated with starter diet formulations is changing very rapidly.
The Phase ll diet can be fed from a body weight of7 to 12 kg. Under some circumstances, producers will find that
such a diet wiII provide satisfactory performance for pigs weaned at 4 weeks ofage, avoiding the need for the more
expensive Phase I diet. Success will depend on such factors as quality ofthe nursery, health status ofthe pigs and
overall management skills ofthe herdsman.
The Phase rI1 diet is the simplest in design, requiring no expensive plasma proteins, whey powders, etc. Blood meal
would only be used ifeconomical. Whey powder could be used ifproblems are observed, but under reasonable
conditions, whey powder will not be required ifthe previous feeding program has been adhered to.
182

201. Photo 8-3.
Source: Patience and Christison, 1988.
NB. Four week trial, commencing immediately upon
weaning
Table 8-6. Effect of Medication on the Performance
ofWeanling Pigs in a High Health Herd.
As the weaning age rises, the Phase I diet will
become less expensive as a greater portion of the
energy and protein can come from plant sources.
If the pigs are weaned at 21 days ofage or older,
they should receive the appropriate diet in Table 8-4
for a period ofat least one week, before switching
gradually to the Phase Il diet.
While such diets are expensive, they are conswned
in relatively small quantities. so the cost per pig is
quite small. For example, at the time ofwriting, feed-
ing the "later wean" Phase I diet for one week after
weaning would cost less than $1.75 per pig. The fi-
nal decision on the use of such diets rests with its
impact on the overall profitability of the farm. The
cost per tonne of feed tells only a part ofthe story.
The Phase I diet is designed to be fed from the
time of weaning until the pig reaches 7 kg, or for at
least one week, whichever is longer. lt may also be
used as a creep feed. A variety ofPhase 1 diets are
provided in Tables 8-4 and 8-5, depending on the
age at weaning. In general, the younger the age at
weaning, the lower the level ofstarch and vegetable
proteins and the higher the desired levels of lactose
and milk proteins. For pigs weaned at less than two
weeks ofage, lactose levels should be in the range
of20% or more. Spray-dried plasma proteins,
spray-dried blood proteins and spray-dried red
blood cells have all proven beneficial. The exact
levels required will depend on conditions within the
barn and will, ofcourse, be influenced by economic
considerations.
0.47
0.70
1.48
Medicated
0.37
0.58
l.56
Control
Average daily gain (kg)
Average daily feed (kg)
Feed conversion
Diet Formulations
Many alternatives are available in developing
effective weanling feeding programs. Diets
presented in this chapter are offered as examples
only.
Producers are strongly encouraged to discuss their
specific needs with a qualified nutritionist as the
formulation ofstarter diets is a highly specialized
science, one which is advancing at a rapid rate.
than com, groating oats represents a method to
enhance the digestible energy content ofwhat might
otherwise be lower energy feeds. Naked oats and
dehulled barley represent another alternative to
increase the energy content ofthe feed, but their
value in starter diets has not been fully defined.
There is a move towards keeping pigs in the nursery
longer, until the) are 35 - 45 kg. Over-crowding must
be avoided.
Feed Additives
Antibiotics
There is little doubt that antibiotics employed for
growth purposes are economical in diets for pigs up
to 25 kg body weight. Research at the Prairie
Swine Centre, a high health herd. confirms this
conclusion (Table 8-6). In this particular experi-
ment, the medication increased net income by about
one dollar per pig.
The practice has attracted some recent criticism,
particularly related to environmental loading ofzinc
via the slurry. Such criticism can be tempered by
only using zinc oxide when diarrhea is a problem
and, even then, only for the necessary period of
183

202. time. Such guidelines also make economic sense.
ln addition, there are legal implications, as such
high levels ofzinc cannot be added to the feed
without a veterinary prescription.
Zinc Oxide
A number ofyears ago, research in Denmark
revealed that adding zinc to the diet ofnewly-
weaned pigs reduced the incidence of diarrhea,
improved growth rate and reduced mortality. Not
surprisingly, the use ofzinc supplements has grown
rapidly in the interim. Generally, the recommenda-
tion is to provide 2.5 to 4.0 kg ofzinc oxide per
tonne offeed for lO to 20 days post-weaning.
Copper Sulphate
Copper sulphate is a relatively common growth
promotant added to many starter diets. It is
relatively inexpensive, and for this reason, its use is
almost automatic in many situations. However,
concerns about the environment, recognition that
the response to copper sulphate is not universal and
the appearance of"sticky" droppings from treated
pigs has tempered its use in recent years. If
included in the diet, the exact amount will depend
on local legislation, but is typically in the range of
125 ppm copper as copper suJphate.
Organic Acids
High pH is conducive to the proliferation of
pathogenic bacteria in the gut ofthe pig. For this
reason, diets are formulated to help keep pH low
and thus favour the growth of"good" bacteria. An
upper gastrointestinal tract pH below four is pre-
ferred; with some kinds ofdiets, and under certain
conditions that are not fuJly understood at this time,
the pig finds it difficult to maintain a low gastroin-
testinal pH. To assist the pig in this regard, organic
acids may be added at 0.5 to 3.0% of the diet. In all
cases, manufacturers recommendations must be
followed.
The observation that organic acids are not always
beneficial may be due to the fact that pH is not
always excessively high. Some research has
suggested that mixtures of acids will be more
beneficial than single additions. The response to
organic acids will generally be greater in simpler as
compared to complex formulations. As with all
feed additives, selecting the right conditions for
their use is critical to their success.
The Pig's Environment
Temperature
The weanling pig presents a unique set ofcircum-
stances in terms ofestablishing an ideal thermal
environment. In particular, low post-weaning feed
intake elevates the pig's thermal requirements; for
example doubling the newly-weaned pig's feed
intake reduces its lower critical temperature from
32°C to 26°C! This is due to the body heat gener-
ated by normal digestion and metabolism. Conse-
quently, room temperature must be linked to the
piglet's feed intake.
Various components oftbe nursery facilities may
contribute to the overall thermal environment.
While the effect of moisture and draughts on pig
comfort are well known, the impact ofcold walls,
floors and ceilings, in fact, any cold surface, which
increase radiant heat losses from the pig, lower the
effective ambient temperature relative to measured
temperature. Clearly then, in addition to warm air
temperatures, well-insulated walls and ceilings are
critical to piglet comfort.
As a rule, newly-weaned pigs should be main-
tained initially at about 30 to 32°C, due to poor
feed intake, lowering the temperature by about I°C
every 2 to 3 days during the first week and by
l to 2°C each week thereafter. The most important
consideration, however, is to watch the activities of
the piglets. Ifthey shiver and huddle, they are too
cold and the temperature should be raised; however,
remember that weanJings are highly motivated by
social interaction, so lying in close proximity to
other pigs should not be interpreted as huddling!
The objective is to keep the temperature warm
enough to prevent huddling, but no warmer.
Temperature variation is also a particular concern
in the nursery. Twenty-four hour fluctuations in
excess of 2°C have been shown to reduce both
growth rate and feed conversion efficiency. It
should be noted that so-called high-low thermom-
eters may underestimate the extent oftemperature
184

203. Table 8-7. Recommended Floor Space Allowances for Weanling Pigs.
Body weight, kg Fully-slatted Partially-slatted Solid, bedded
0.035 X BW0667
0.039 X BW0667 0.045 X BW0·6<,7
10 0.16 0.18 0.21
20 0.26 0.29 0.33
30 0.34 0.38 0.44
Adapted from Recommended Code of Practice for the Care and Handling ofFarrn Animals.Pigs, Ag. Canada, 1993.
fluctuation in the nursery, because they do not
record rapid changes very effectively. For example,
in mercury thermometers, the response to tempera-
ture change is quite slow and may underestimate
fluctuation by 50% or more.
While too low a temperature is undesirable,
failure to lower room temperature as the pig's
thermal needs change will suppress appetite and
lower overall animal performance. Managing room
temperature in the nursery is not a simple task,
because the consequences oferror are severe.
Floor Space
Overcrowding is a particular concern with the
weanling pig. Because it is a social animal and
often chooses its behaviour based on that ofits
penmates, space to express such behavioural pat-
terns is important. Table 8-7, extracted from the
Recommended Code ofPractice for the Care and
Handling ofFarm Animals:Pigs, provides a useful
guideline on this subject.
Feeder Design
Feeder design is often overlooked, in part because
there are few objective guidelines. It is clearly
understood that weanling pigs tend to eat in groups,
so multiple-space feeders are preferred over single-
space feeders. If feeders are too large, however,
pigs will tend to dung in one or both ends of the
feeder. As a general rule, 7.5 to I0.0 cm of feeder
space should be allowed per pig. Other than that,
the design should allow easy access to the feed
while concurrently minimizing waste and spill.
Additional Reading and References
Nelssen, J.L., R.D. Goodband, S.S. Oritz and M.D.
Tokach. 1995. The effect of weaning age on
nursery pig behavior and growth performance. In.
(Foxcroft. G., ed), Advances in Pork Production,
Vol. 6, pp. 95-112. University ofAlberta, Edmon-
ton, AB.
Pettigrew, J.E. and J.T.F. Stairs. 1991. The impact
ofstarter diets on the subsequent growth ofswine.
In: Proceedings ofthe Minnesota Nutrition Confer-
ence, pp. 163-170, Minneapolis, MN.
Pettigrew, J.E. 1995. Nutrition of the convention-
ally weaned pig. In. (Foxcroft, G., ed), Advances in
Pork Production, Vol. 6, pp. 85-94. University of
Alberta, Edmonton, AB.
Sheridan, M. 1995. Advantages ofmultiple site
production with emphasis on herd health manage-
ment. In. (Foxcroft, G., ed), Advances in Pork
Production, Vol. 6, pp. 147-153. University of
Alberta, Edmonton, AB.
VIDO. 1991. Swine Nursery Design. 2nd Ed.
Veterinary Infectious Diseases Org., Saskatoon, SK.
185

204. 186

205. 9. FEEDING MANAGEMENT OF MARKET
HOGS
Approximately 60% ofthe total cost of pork
production is associated with growing out the feeder
pig. Traditionally, more attention is paid to
managing sows and starter pigs than growing-
finishing pigs. The breeding and farrowing areas are
often considered more challenging and therefore,
according to many people, deserve more of
management's attention. The indifference shown to
the feeder barn probably stems from the presence of
apparent problems in the sow-related areas and from
a lack ofappropriate records in the feeder barn.
Records are very important in identifying both
production problems and opportunities to improve
performance in the feeder barn. Fortunately, as better
record keeping systems and performance monitoring
systems become available, and as potential
improvements in profitability become more apparent,
more attention is paid to the feeder barn. Feed is the
largest single expense in any swine operation.
Although there must be an absolute minimum, the
variation in feed costs among farms is proofthat
major savings can be achieved in this area. Even on
farms with high management standards, differences
in feed costs (up to 25% per pig) still exist.
Goals for the Feeder Barn
Establishing production objectives for the feeder
barn is important. These objectives will vary from
farm to farm depending on a variety of circumstances
including pig genotype, health status, environmental
Photo 9-1.
Approximately 60% of the total cost ofproduction is
associated with the feeder barn. Feed is the majD.r_npe11st>._
control, pig density, and diet composition. The goals
defined in Table 9-1 are a reasonable guide for most
feeder barns. These goals arc identified as good,
better, and best to denote the ease with which they
can be achieved. The values in the 'good' column
are being achieved consistently by many producers.
Those in the 'better' column are being met by some
producers so are currently possible. The goals in the
'best' column are not all being achieved consistently
at the present time, but the potential exists to meet or
exceed them under the right combination of
management. The tremendous gains made in the
recent past provide confidence that the goals in the
'best' column will be met or surpassed in the near
future.
Table 9-1. Goals for the Feeder Barn.
Goal Level
Good Better Best
Age at 105kg 160 150 140
Days in Feeder Barn 110 100 90
Feeder Barn (20 - 105 kg)
Avg Growth Rate (g) 775 850 950
Feed Conversion 3.20 2.85 2.60
Mortality(%) 2.0 0.5 0.1
Carcass Index 107 110 112
These goals are to be used only as guidelines. The
overall objective is to maximize profit. Establishing
the proper goals for your operation is just as
important, if not more so, than your capital outlay.
For example, although superior pig performance is a
desirable goal, setting a goal ofthe highest standard
ofperformance may not be profitable because the
extra expense needed to produce the high standard
may not be regained from the market. Setting
arbitrary goals without records to back them up may
also be costly. A strict capital invested to goals
accomplished ratio does not exist, either. In some
cases, the overall goal of profitability can be attained
with a low capital approach that frees the operation
187

206. from heavy debt and cushions it against depressed
prices and high interest rates. Establishing your
goals will help you determine the areas important to
you, and how much you are willing to spend in each
of those areas.
Once production goals have been established, the
next step is to develop feeding and management
strategies to accomplish these goals. Finally, a record
keeping system should be implemented to monitor
important production parameters, such as days in the
barn, feed usage, carcass lean yield, and mortality.
Lean Tissue Growth in Growing-
Finishing Pigs
ln feeder pigs, both the growth rate and the
composition ofgrowth should be considered.
Growth is the increase in body weight with time or
age of the pig. A typical growth curve is shown in
Figure 9-1. This curve, a sigrnoida1 growth curve,
represents a pig's theoretical growth pattern from
fetus to adulthood. It is clear that at an early age, the
pig's gain is at an increasingly rapid rate; later, rate of
gain is essentially constant and later still, decelerates
as the pig approaches full, mature weight. This curve
represents a pig's potential but under normal farm
conditions Jess than optimal growth may occur due to
limitations in genetics, nutrition. housing, disease, or
other management aspects. Furthermore, the curve is
influenced by sex - boars and barrows grow faster
than gilts. Pigs are generally slaughtered at a weight
which is under halftheir mature body weight and at a
time that growth rates are just starting to decline.
Time_
Figure 9-1. Sigmoidal Curve Describing theTheoretical
Growth of the Pig from Conception to Adulthood.
188
In young pigs, growth consists largely of bone and
muscle, but as the pig reaches maturity, fat deposition
occurs at an increasingly rapid rate. For example, in
the new-born pig, muscle and bone represent 29 and
19%, respectively, oftotal empty body weight while
fat represents less than 4% ofthe total. By 28 weeks
ofage, muscle and bone represent 32 and 7%,
respectively, and fat has risen to 35% ofthe total
(Figure 9-2).
• FatH%
• Bone3U%
CJ MJsde 56.2%
Figure 9-2a.
28WEEKS
• Fat46.9%
• Bone 10.1%
D �e43,0%
Figure 9-2b.
Figure 9-2. Relative Proportions of Muscle, Bone and
Fat in Pigs at Birth and 28 weeks of Age (From
McMeakan, 1940).
Since consumers demand high quality lean pork
products, it is in the producer's interest to maximize or
optimize the accretion (growth) ofmuscle, or Jean body
mass and minimize body fat deposition. One important
additional advantage is that pigs are much more effi-
cient in producing lean tissue than fat. Pigs require
about four times the amount offeed to produce one kg
ofbody fat compared to one kg ofbody lean. This
requirement is due largely to the difference in water
content: fat and lean tissue mass contain about 5% and
70% water, respectively. The pork producer can employ
a number ofstrategies to manipulate lean tissue growth
in the pig. These strategies include selecting genetically
lean animals for breeding, maintaining a high herd
health status, carefully formulating market hog diets,
and manipulating feed intake.
BIRTH

207. Fat and lean content ofthe carcass is measured in
many ways around the world. The most common
method is to take back fat measurements at specific
locations over the last rib and at various distances from
the backbone: P 1, P2 and P3 (Figure 9-3). Back fat
measurements, in turn, can be related to total body fat
content. Back fat measurements can be used to
estimate body lean content because there is an inverse
relationship between body fat and body lean content.
Figure 9-3. Description of Pl, P2, and P3 Fat
Measurements, Taken over Last Rib and Atop the Loin
Eye Muscle.
In the Canadian swine carcass grading system, a
special probe is used to determine the measurements,
taken 70 mm from the backbone and between the 3rd
and 4th last ribs, used to estimate carcass lean con-
tent. Since early 1995, the lean yield is expressed as
a percentage ofthe cold carcass sides, rather than of
the warm carcass. Depth of back fat and the loin eye
muscle is determined at this site. This information is
incorporated into an arithmetic formula to estimate
carcass lean yield. The estimated lean yield and
dressed carcass weight is then used to arrive at an
index, which becomes the basis for settlement of
value per kg of carcass (Table 9-2). The actual index
value that is assigned to each yield class in each
carcass weight category may vary between provinces
and even between packers within provinces.
Information on carcass lean yield and growth rates
can be used to determine lean growth rates in
individual groups of feeder pigs. To calculate lean
growth rates, assume that the Jean content in a 25 kg
pig is constant at 35% of live body weight, that
carcass dressing percentage is relatively constant at
79% of body weight in market weight pigs, and that
the difference in weight between hot carcass weight
and cold carcass sides is 8 kg. This 8 kg represents
the weight ofthe head, feet, tai1, kidneys and leaf fat,
(i.e. the parts that are removed from the carcass
before the weight ofthe cold carcass sides can be
determined).
Calculating Lean Growth Rates:
Required information:
- initial weight: 25 kg
- final weight: I 05 kg
- average carcass lean yield (from carcass grading
slip): 59%
- average days in the growing-finishing barn: I 03
Assumptions:
- difference in weight between hot carcass and cold
carcass sides: 8 kg
- lean content at initial weight: 35% of body weight
- carcass dressing percentage: 79% of body weight
Calculations:
- lean mass at initial weight:
25 kg x 35%/100 = 8.75 kg
- Jean mass at final weight:
(105 kg x 79%/100 - 8kg) x 59%/ I 00 = 44.22 kg
- lean growth rates:
1000 x (44.22 kg - 8.75 kg) I 103 days
= 344 g/d
Alternatively, lean growth rates can be estimated
from days in the feeder barn and carcass lean yield as
outlined in Table 9-3.
Monitoring lean tissue growth rates in the grower-
finisher barn is important for three reasons. First,
lean tissue growth, representing the accretion ofthe
valuable parts in the pig's body, is a good indicator
ofproduction output. Second, observed lean tissue
growth rates allow for an objective comparison of
production efficiency between various production
units. Lean tissue growth rates are important for
determining whether or not pigs are performing at a
level close to their performance potential. Third,
estimates of lean growth rates and lean growth
189

208. Table 9-2. Saskatchewan Carcass Grading Grid (effective March 6, 1995).
°'°'r- 0 �
°' °'
t'-C"'IOt'-OViM000
0,. 0,. 00 00 00 00 00 00 r-- I"--
ViC"'IOOOO...;t'NO,....;t-0
0 00 °'°' o,. 0,.00 0000
00001"--Vi t--...;t'OOO
00 00 Oo,. o,. 0000
°'°'<o r- °'00 00
...;t'MNOl'-...;t'Noor-o
000 °'°' o,.
·�
....
�
.....0
E
E
00
N Ooo r- Vi MN 00 MO
O Oo,. o,. a, o,.o,. oo 00 00
OOOOOOOOViC"'IO
00 00 00 00 00 00 I'- I'- r- I"--
°'Vi o-
0 '°00 00
00 0 Vi Vi 0 C; 0- 0
01....:oo;oor-OO°'
00 0 0 0 Vi Vi Vi Vi Vi
N
'°/
-NM...;t'ViOl'-000,0
E:::,
E
.5
E
�
oI
E
...._...
e;.;:::
0
£
190

209. Table 9-3. Observed Lean Growth Rates in Growing-finishing Pigs (25 to 105 kg body weight) in Relation to
Growth Rates and Carcass Lean Yield Content (75-85 kg carcass weight)*.
Growth rate (g/d)
Estimated lean yield(%) >850 800-850 750-800 700-750 <700
> 61 High High High Medium Medium
59 - 61 High High Medium Medium Unimpr.
57 - 59 High Medium Medium Unimpr. Unimpr.
< 57 Medium Medium Unimpr. Unimpr. Unimpr.
* relates to carcass weights between 75 and 86.99 kg in Saskatchewan; 1995 Canadian carcass grading system;thc high,
medium, and unimproved lean growth rates correspond to lean growth rates of approximately 380, 340, and 300 g/d.
potential are essential for developing cost-effective
feeding strategies in individual production units.
Clearly, the objectives in raising pigs are to
optimize lean tissue gain and to minimize the accu-
mulation ofbody fat. The overall goaJ is to meet
these objectives profitably.
Feed Intake in Feeder Pigs
Feed intake is closely related to growing-finishing
pig performance. Tn addition, estimates of feed
intake are required for accurate feed formulation.
Unfortunately feed intake appears to vary consider-
ably between different feeder pig units. As it is
affected by many factors, it is difficult to accurately
predict feed intake as well. These factors are associ-
ated with the animal (e.g., body weight, sex, geno-
type, health status), the feed (e.g., dietary energy
density, levels ofother nutrients, ingredient composi-
tion, freshness, feed processing, bulkiness, water
supply) and the environment (e.g., effective environ-
mental temperature, animal density, group size, pen
design, feeder design and location).
In 1987. the North American National Research
Council (NRC) presented a mathematical equation to
predict the voluntary daily energy intake in growing-
finishing pigs. When this equation was introduced,
digestible energy (DE) content ofthe diet and the
pig's body weight were recognized as two important
factors that affect feed intake. More recent estimates
of feed intake on commercial Canadian pig farms
suggests that pigs under commercial conditions are
more likely to consume quantities of feed that are
equivalent to 90% of the daily DE intake in growing-
finishing pigs as suggested by NRC ( 1987). Figure
9-4 represents feed intake curves for feeder pigs
consuming a diet with a DE content of 3150 or 3400
kcal per kg and at 90% ofvoluntary feed intake
according to NRC (1987). This graph may serve as a
benchmark to compare feed intakes on individual
pork production units.
Recent work at Purdue University clearly demon-
strates that the effect ofpig genotype on voluntary
feed intake. Their studies demonstrate that in feeder
pigs managed under the same conditions and fed
similar diets, the difference in feed intake between
the various lines of pigs may be as high as 20 - 30%.
Pigs that have been selected for (lean) feed effi-
ciency, rather than for lean growth rates, may have
lower feed intake capacities as compared to the un-
selected controls. Another factor associated with the
animal is that feed intake is reduced (5% or more) in
pigs with (sub-clinical) diseases as compared to pigs
managed under minimum disease conditions. For the
development ofsplit-sex feeding programs, the
difference in feed intake between barrows and gilts
should be considered. On average, the difference in
feed intake between the two sexes is 10%. However,
it tends to increase at increasing body weights and
the difference in feed intake between the two sexes
will vary with pig genotype and the environment (see
split-sex feeding later in this chapter).
One of the main feed factors that determines feed
intake is the dietary energy density. Finishing pigs
are generally able to compensate for reduction in
191

210. dietary energy density (with an increase in daily feed
intake) in such a manner that the daily energy intake
remains constant. Grower (and starter) pigs are
generally unable to adjust feed intake with changing
energy densities. For these pigs physical feed intake
capacity, or "gut fill", determine feed intake, An
increase in dietary energy density will result in
increases in the daily feed intake. It should be
stressed that these principles do not apply to extreme
dietary energy densities and will be affected by
environmental conditions. The effect ofdiet energy
density on daily energy intake can have important
consequences for the optimum energy density in the
diet (see "diet formulation" later in the chapter).
Other nutrients have limited effects on feed intake
when present at levels in the feed which are within
practical range. Iffeed is the suspected problem with
intake, then the various aspects of feed formulation
and preparation should be quickly evaluated. These
include: ingredient composition and quality (inclu-
sion levels of "unpalatable" ingredients, freshness,
molds and toxins), feed processing and mixing
accuracy (check for the content of the major nutri-
ents: see chapter l0) and the storage and handling of
the prepared feed (freshness, contamination ofmolds
after feed preparation).
3.5
,::, 3
°'.Y.
2.5
or.Y.
2«s+-
e
i:,
1.5
Q)
Q)
u,
0.5
- L---
-- - . - - ..
--i.-- .. -..
�- ..
./
V-·
":: . -3150 Kcal DE/k��
v - - 3400 Kcal DE/kg
20 30 40 50 60 70 80 90 100 110
Body weight, kg
Given the above considerations, it is important to
monitor feed intake as well as the main factors that
affect feed intake.
and not be sensitive to mechanical failure. No sharp
objects or protruding objects should be present. If
well designed single space feeders arc used, one
feeder is sufficient for up to 12 pigs. When the water
nipple is placed inside the feeder (wet feeders), feed
intake is generally higher ( l - 7%) as compared to
that ofstandard dry feeders. Problems with wet
pens, water wastage and the developments of molds
are more likely to occur when wet feeders are used.
In terms of the environment, the effective environ-
mental temperature (the actual temperature that the
pig "feels"; the net result ofair temperature, air
movement, humidity, floor type and wetness of skin
and floor, etc.), pig density and the design and
management of the feeder are important factors that
can affect feed intake. For example, for pigs that are
under mild heat stress an increase in the effective
environmental temperature by l°C will reduce feed
intake by approximately l% and 2% in grower and
finisher pigs, respectively. As far as pig density is
concerned, the actual space allowance is more critical
than the number of pigs in a group. Feed intake will
reduce by about 3% and 2% per 0.1 m2 reduction in
floor space per pig in grower and finisher pigs,
respectively.
Feeders should be designed and located in such a
way that pigs can assume their normal eating behav-
iour. The design should discourage feed buildup in
the feeder. Feeders should be easily adjusted to
maximize feed intake while minimizing feed wastage
192
Figure 9-4. Typical Feed Intake Curve for Growing
Pigs Consuming a Diet with a DE Content ofEither
3150 or 3400 kcal/kg. (Feed intake is equivalent to
90% ofvoluntary feed intake according to NRC
1987*),
*According to NRC 1987, the voluntary daily DE intake
can be predicted from body weight (W, kg). DE intake
(Kcal/d) = 13,162 x (l-e-·0176""').
Feed Utilization in Feeder Pigs
Pigs use feed for three major purposes: body
maintenance functions, lean tissue growth, and body
fat deposition (Figure 9 -5). Even ifthey do not
grow, pigs require a certain amount of food to
maintain vital body functions such as circulation,
respiration, and digestion. Only dietary nutrients that
are supplied in excess ofmaintenance requirements
can be used to support growth, either in the form of
lean tissue or body fat. Maximizing the utilization of
feed for growth means minimizing the amount of
feed required for maintenance functions. To maxi-
mize growth means that pigs should be maintained in
a comfortable environment so they do not expend

211. Figure 9-6. The Effect of Feed Intake on Lean Tissue
Growth and Body Fat Deposition in Finishing Pigs
with Average ("average" pig) and High ("good" pig)
Lean Tissue Growth Potential*.
* The maximum lean tissue growth rate is considerably
higher in pig type b than in pig type a. To achieve the
maximum lean tissue growth rate, the "good" pig requires
more feed than the "average" pig. Iffeed intake in both
types of pigs were restricted, e.g., at 2 kg/d, no difference
in performance would be observed between the two types
ofpigs.
The relationships between feed intake, lean tissue
growth, and body fat deposition have been explained
in Figures 9-5 and 9-6. Figure 9-7 presents the effect
of feed intake on growth rate, feed efficiency, and
carcass Lean content for growing and finishing pigs
with average lean growth potential. In
growing pigs, feed intake limits lean growth so
should be maximized for optimal growth rate and
feed efficiency. ln finishing pigs, feed efficiency and
carcass value can be improved by moderately
restricting feed intake. The optimum level offeed
intake in the finishing phase is thus determined by
the relative importance of feed efficiency (feed cost),
lean yield in the carcass (the carcass grading system),
and the value ofthroughput (the cost ofspace). Tn all
these relationships it is assumed that performance is
determined purely by energy intake and that other
nutrients, such as amino acids, vitamins, and
minerals, do not limit animal performance.
Lean
Fat
3
"good" pig
,,
'
'' ·•..
" - -
/ '�';'. '
..
2 3 1 2
Feed Intake (kg/d)
"average" pig
1
Gain
Lean
Fat
Maintenance
Gain
0
Feed Intake
Figure 9-5. Relationship between Feed Intake and
Tissue Accretion Rates in Growing Pigs.
energy adapting to their environment (e.g., shivering
to keep warm). Ifthe environmental temperature is
suitable, pigs should not require feed to maintain a
constant body temperature, or combat diseases.
When feed intake is increased above that required
for maintenance, lean tissue growth in pigs rapidly
increases (Figure 9-5). However, even at very low
levels offeed intake, growing pigs will deposit some
(essential) body fat. It is practically impossible to
avoid the deposition ofany body fat in growing pigs.
In some pigs, and at high levels of feed intake, intake
may exceed the amount required for maximum lean
tissue growth rates. If so, lean growth is not limited,
but large quantities ofbody fat, which result in
reduced carcass lean yield and poor feed efficiency,
will also be deposited. This situation generally
OCCW'S in finishing pigs (greater than 60 kg body
weight) that are fed ad libitum, but may occur at
lower body weights in pigs with poor lean growth
potential. On the other hand, even a high feed intake
may be insufficient to maximize lean growth up to
body weights greater than 60 kg in boars and other
animals with extremely high lean tissue growth
potential (Figure 9-6).
193

212. Feed Intake
required feed Intake to just
ma.ximize lean growth
PIG TYPE:
O Unimproved
•Improved
Diet LYSINE level, %
0.5 0.65 0 .8 0.95
500
dietary lysine levels and lean growth in two types of
pigs is demonstrated in Figure 9-8. At low levels of
lysine in the diet there is no difference in
performance between the two types ofpigs. Only
when dietary lysine levels are increased can pigs with
the higher lean tissue growth potential demonstrate
their potential. Pigs with unimproved lean tissue
growth potential will not respond to the increase in
dietary lysine levels. To avoid over feeding
expensive nutrients to an animal that does not require
them, and to ensure that an animal with high
performance potential receive sufficient quantities, it
is important to monitor lean growth rates (see earlier
section on lean tissue growth) and to establish the
animal's lean growth potential.
't,
-a,
£
j
0..a,
c
nl
Q)
...I
··gain
- feed: gain
-lean gain : fat gain
··gain
- feed: gain
- lean gain : fat gain
-
---
Feed Intake
'-,
''-,
<,
. ....:
<,
......
......
......
Figure 9-7a.
'-,
'-,
<,
<,
. ...:
'......
............. ------
Figure 9-7b.
Figure 9-7. Relationship between Feed Intake and
Performance in Growing Pigs where Energy Intake
Limits Lean Growth (Figure a), and in Finishing Pigs
where Feed Intake does not Limit Lean Growth
(Figure b).
Factors Affecting Nutrient
Requirements in Growing-Finishing
Pigs
Due to differences in animal performance
potential, health status. body weight, feed intake,
environmental conditions, and other factors, there is
a tremendous amount ofvariation in the optimum
nutrient levels in diets for different groups offeeder
pigs. Before any attempt is made to formulate diets
for feeder pigs, the main factors that determine the
optimum nutrient levels in the diet must be
considered.
The lean growth rate in the growing-finishing
pig is the single most important factor that
determines the daily requirements for amino acids
and one of the main factors determining requirements
for energy. For example, the relationship between
Figure 9-8. Effect of Dietary Lysine Levels and Pig
Type on Lean Growth Rates (Stably 1989, University of
Kentucky).
Estimates of lean tissue growth potential in
various types ofpigs may be provided by the
breeding stock supplier. Do not, however,
underestimate the effect ofthe animal's health on
lean tissue growth potential. The presence ofdisease
can effectively reduce the animal's lean growth
potential (Table 9-4) no matter how high its
estimation. Breeding stock is often produced and
evaluated in herds with a health status much higher
than that in many commercial pork production units.
Estimates oflean growth potential that are derived
from animals tested in herds with a high health status
may not apply to their offspring that are managed on
commercial farms.
194

213. Table 9-4. The Effect of Health Status on Performance
in Growing-Finishing Pigs (Williams 1994, Iowa State
University).
Exposure to Disease Low High
Feed intake, kg/d 2.47 2.36
Growth rate, kg/d 0.89 0.78
Feed: Gain 2.76 3.04
Muscle in the carcass, % 57.0 52.5
The animal's lean growth potential may be
estimated from observed lean growth rates in the
feeder barn (sec Table 9-3). However, take care in
interpreting lean growth rates. Other factors, such as
feed intake or unbalanced diets, rather than the
animal's potential, may affect observed lean tissue
growth rates.
A pig's daily nutrient requirements increase as it
grows heavier, but so does its feed intake. In fact, a
pig's feed intake increases more rapidly than its
increase in daily nutrient requirements. As a result,
nutrient levels in the feed can be gradually decreased
as the animal grows (Figure 9-9). This concept
forms the basis ofphase feeding. Phase feeding uses
different diet formulations to meet the pig's nutrient
requirements at each stage ofits production, which
reduces over-feeding excessive quantities of
expensive nutrients.
Because animals require nutrients on a daily basis,
estimates offeed intake per day are required to
determine the optimum nutrient level in the diet.
This estimation is especially important for amino
acids in finishing pig diets. For example, based on
the animal's lean growth potential, a finishing pig
may require 20 g of lysine per day. As there is
generally no effect ofenergy intake on lean growth
rates in finishing pigs, daily lysine requirements are
not affected by feed intake. ffthe feed intake in the
finishing pigs is 2.50 kg per day then the optimum
lysine level in the diet should be 8 g/kg, When feed
intake is 3 kg/d, the lysine level should be 6.66 g/kg.
This reduction in required dietary lysine level will
substantially reduce the cost ofthe finishing diet.
In growing pigs, up to approximately 60 kg body
weight, energy intake generally limits lean growth. A
reduction in daily energy (feed) intake will reduce
lean tissue growth and the daily requirements for
amino acids. Iffeed intake happens to be reduced in
grower pigs, there is no need to increase the dietary
amino acid levels in the remaining food intake. For
this reason, it is more important to balance the amino
acid levels in the grower pig diets based on amino
acid to energy ratios than any other ratio, and to
formulate finisher pig diets based on daily amino
acid intakes.
Question: When should I determine the optimum
amino levels in the pig's diet based on daily
intakes and when based on amino acid to energy
ratios?
Figure 9-9. Change in Required Dietary Nutrient
Levels in Relation to Body Weight.
Answer: Base finishing pig diets on daily intakes; base
grower (and starter) pig diets on amino acid to energy
ratios.
Why: ln finishing pigs, energy intake docs not
generally limit lean growth. As a result, there is no
relationship between energy (or feed) intake and body
protein deposition; daily amino acid requirements arc
not affected by feed intake. In growing pigs (up to
approximately 60 kg body weight), energy intake
usually limits Jean growth. An increase in feed or
energy intake will result in an increase in body protein
deposition. As a result, the daily amino acid
requirements increase. The optimum amino acid to
energy ratio in diets for growing pigs is relatively
constant over a range of feed intakes.
J-Nutrient requirements l
t
�0
ai
>
�
-eCl)
·;:
-:::,
c
-Cl)
i:3
20 40 60 8 0 100 120
Body weight, kg
195

214. The environment also affects a pig's nutrient
requirements, especially nutrients needed for body
maintenance functions. In modem and well
managed, confinement growing-finishing pig
facilities, environmental conditions can be optimized
and the amount offeed required for maintenance
minimized. Ifthe environment is too cold,
maintenance energy requirements quickly increase.
Under cold stress conditions, growing pigs (25 to 60
kg body weight) require approximately 25 g ofextra
feed to maintain a constant body temperature per °C
drop in environmental temperature. For finishing
pigs, this value is approximately 40 g offeed. This
demand means that total feed usage would increase
by approximately 15% for growing-finishing pigs
kept in an environment that is effectively lO °C too
cold for them. This usage is equivalent to a drop in
feed conversion ratio from approximately 2.9 to 3.3.
The cold environment is one ofthe major reasons for
the poor feed efficiency observed during the winter
months in low-cost, outdoor feeder pig housing
systems. Remember that the effective environmental
temperature to which pigs are exposed is determined
not only by the environmental temperature but also
by other factors such air speed, air humidity, floor
type, dryness of the floor, and the pig's body
condition.
In developing feeding programs for feeder pigs it is
also important to consider the production objectives
and the economic conditions. Different feeding
strategies and diet compositions are required when
the objective is to maximize income per pig rather
than income per pig place per year, or when
economic conditions change.
Nutrient Allowances and Diet
Formulation
The basic concepts ofdiet formulation are covered
in chapter 5. In that chapter, the importance of
fonnulating diets on the basis ofavailable rather than
total nutrients is emphasized, as well as the
importance ofmonitoring feed ingredient quality,
feed preparation, and feed handling. As we continue
to meet the animal nutrient requirements more
closely through phase feeding, split-sex feeding, and
feeding for different genetics, these basic concepts of
diet formulation and quality control become
increasingly important.
196
Due to the many factors that affect nutrient
requirements, there is a wide range in recommended
nutrient levels for growing-finishing pigs. For
example, recommended lysine levels may range from
as high as 1.3% in early grower diets for pigs with
extremely high lean growth potential to as low as
0.5% in late finisher diets for pigs with poor lean
growth potential that consume large quantities of
feed. This variance again stresses the importance of
recognizing the main factors that affect nutrient
requirements in various groups of pigs for
developing unique management and feeding
strategies for individual production units. It also
supports the need for a factorial, or modelling,
approach to estimating nutrient requirements in
which the main factors that affect nutrient
requirements are considered. However, when such a
modelling approach is used, different agencies or
researchers will still provide different estimates of
nutrient requirements. For example, the estimated
lysine requirements for a 50 kg pig with a given rate
oflean growth {body protein deposition), estimates
may vary by as much as 30% (Table 9-5). Obviously
our knowledge ofpig nutrition is not yet complete.
As we continue to improve our understanding of
nutrient utilization in pigs, these discrepancies will
disappear.
Table 9-5. Estimated Available (Apparent lleal
Digestible) Lysine Requirements for a Growing Pig at
50 kg Body Weigbt1
•
Moughan et al., 1987 .54%
Stranks et al.. 1988 .59%
Fuller et al., 1989 .43%
TMV2, 1991 .62%
Moughan, 1992 .65%
Whittemore, 1993 .58%
I
Average lean tissue growth rate (340 g/d according to the
Canadian definition oflean , this is equivalent to 130 g/d of
body protein deposition). The pig consumes 2.2 kg of a
diet with a DE content of 3150 kcal/kg (feed intake is
equivalent to 90% ofNRC [1987)). Pigs are assumed to
be in a thermo-neutral and relatively disease free
environment.
2
Technisch Model Varkensvocding.

215. Table 9-6. Estimation of the Lowest Cost per Unit of
Energy in Growing Pig Diets (varying in energy
density)*.
* Prices ofingredients: barley $80/tonne, wheat $95/tonne,
soybean meal $265/tonne, canola meal $190/tonne, lysine
HCL $3000/tonne, premix $600/tonne.
** Levels ofall nutrients are adjusted with diet's energy
content to ensure a constant nutrient to energy ratio.
Table 9-7. Effect of Dietary Energy Density on the Voluntary
Feed Intake and Performance of Entire Male Pigs between 22
and 50 kg Body Weight (Campbell and Taverner, 1986).
DE content,
kcal/kg 2820 3035 3250 3466 3600
Voluntary Intake, kg/d 2.19 2.21 2.19 2.17 2.05
Voluntary DE, Mcal/d 6.14 6.62 7.10 7.48 7.39
Growth Rate, g/d 695 776 847 898 913
Feed: Gain 3.16 2.89 2.61 2.39 2.25
Carcass P2 14.40 15.30 15.60 16.00 16.40
In growing pigs, physical feed intake capacity, or
gut fill, generally determines feed intake. An in-
crease in diet DE content will thus result in propor-
tional increase in the daily DE intake. As illustrated
by the data in Table 9-7, an increase in energy density
in the diet for growing pigs will result in improve-
ments in both feed efficiency and growth rate. For
growing pigs, the optimum energy density is not only
determined by the cost per unit ofenergy in the diet,
but also by the effect ofenergy density on growth
rate, and thus throughput in the grower barn. As the
animal's Jean tissue growth potential continue to
increase, energy intake will become a limiting factor
up to higher live body weights. This situation may
also mean that finishing pigs with extremely high
lean tissue growth potential may be unable to com-
pletely maintain a constant daily energy intake as the
energy density in the finishing diet is reduced.
Clearly, more information is required on the interac-
tive effects of pig genotype and body weight, as well
as tbermaJ environment and animal density, on the
optimum energy density in the diet.
Diet 2 Diet3
3250 3350
In most practical swine diets, lysine is the first
limiting amino acid. It is thus appropriate to first
35.29 3.12 define the target (available) lysine level in the diet
42.80 75.51 and to derive the required level of other amino acids
18.10 18.15
from that oflysine based on an optimum amino acid
balance (outlined in chapter 3). The suggested
0.70 0.00 allowances ofavailable (apparent ileal digestible)
0.03 lysine in relation to body weight and lean growth
3.11 3.19 rates are presented in Table 9-8. Allowances are
expressed either as lysine to energy ratios or as daily
lysine intakes. These suggestions are based on a
3250 3250 factorial estimation oflysine requirements to support
0.72 0.74 the indicated lean growth rates. A safety margin of
0.47 0.48 about 5% for the grower phase and I 0% in the
3.00
132.62 138.44 146.11
42.10 42.60 43.61
160 155 150.5
3.55 3.44 3.34
11.18 11.18 11.18
Premix
The optimum energy density in feeder pig diets is
determined largely by the cost per unit ofenergy in
the available feed ingredients. As mentioned earlier,
finishing pigs (over 60 kg body weight), are
generally able to adjust feed intake with changes in
dietary energy density in such a way that the total
daily energy intake remains constant. at least when
the diet's DE content ranges between 3000 and 3400
kcal/kg. In other words, if the diet's DE content is
reduced by I 0% from 3300 to 3000 kcal/kg, the
finishing pig will simply consume 10% more feed,
growth rate will not be affected, and the feed
conversion ratio (feed/gain) will simply increase by
10%. In this case, the optimum energy density in the
diets should be based on purely the cost per unit of
energy in the diet as outlined in Table 9-6.
Diet 1
Calculated nutrients:**
DE, kcal/kg 3150
Avail. Lysine,% 0.70
Avail. Threonine,% 0.46
Prices:
$/tonne
$/Meal DE
Estimated Feed usage:
Kg per pig
Feed: Gain
Meal DE : kg gain
DE content, kcal/kg 3150
Ingredient comp.(%):
Barley 59.30
Wheat 17.40
Soybean meal, 47% 15. JO
Canela meal 5.20
LysineHCI
197

216. * The average lean growth rates are 480, 440, and 400 g/d.
for pigs with high, medium, and unimproved lean growth
rates. respectively (see Figure 9-6 also).
Table 9-8. Recommended Allowances of Available (ap-
parent ilea) digestible) Lysine in Relation to Lean Growth
Potential and Body Weight in Growing-finishing Pigs.
High*
2.70 2.35 20.00
(.86%) (.74%) (.67%)
Medium"
2.25 17.50
(.71%) (.61%)
Unimproved"
1.95 15.50
(.61%) (.54%)
finisher diets is already included in these values to
allow for inaccuracies in feed preparation and varia-
tion in feed intake. In comparison to other factorial
estimates of lysine requirements, the suggested
allowances can be considered high (Table 9-5).
However, the suggested allowances are supported by
empirical animal performance studies as well. The
actual recommendations that are expressed as a
percentage in the diet in Table 9-8 relate to a diet
with an energy density of3150 kcal/kg and for pigs
consuming average quantities of feed (90% ofNRC
l987; Figure 9-4). If feed intake is different from the
indicated values or when the diet DE content is
different from 3150 kcal/kg, the available lysine
levels in the diet should be adjusted to maintain a
constant available lysine to energy ratio in the grower
diets, and a constant daily available lysine intake in
the finisher diets.
Question: How do I adjust the suggestions in
Figure 9-8 for the diets on my farm? My pigs
have an average lean growth potential; I feed a
grower and a finisher diet with DE contents of
3300 and 3000 kcal/kg, respectively. I have
established feed intake curves on my farm:
consumption on my grower and finisher diets are
2.2 and 2.7 kg/d, which is equivalent to 85% of
estimated intake according to NRC (1987).
Answer: The available lysine level in the grower diet
should be increased to 0.74 %. In the finisher diet it
should be 0.65%.
Background: The lean growth potential are average so
the recommendation derived for these pigs should be
the average lean growth rates - medium - in Figure
9-8. In the grower diet the available lysine to energy
ratio should be 2.25. At a DE content of3300 kcal/
kg, the available lysine level should be 7.40 g!kg or
0.74%. In the finishing phase, the daily available
lysine requirements are 17.50 g/d. Given the daily
feed intake of2.70 kg, the available lysine level in this
finisher diet is 17.50 divided by 2.70, which is 6.50 g/
kg or 0.65%.
Once the requirements for available lysine are
established, the requirements for the other essential
amino acids can be determined based on the opti-
mum amino acid balance, i.e., the concept of ideal
protein as outlined in chapter 3. It is estimated that
per I 00 g ofavailable lysine, growing-finishing pigs
require 60 to 70 g available threonine, 56 to 64 g of
available methionine plus cystine, and 18 to 20 g of
available tryptophan. At least 50% ofthe methionine
plus cystine requirements needs to be supplied by
methionine. The ratio of these amino acids to lysine
increases with increasing body weight or with reduc-
tions in lean growth potential.
110706045
Body weight
(kg) 25
If only one diet is being used in the feeder barn, do
not use a grower type diet because is too expensive
to feed all the way to market weight. To optimize
profitability, some performance in the early stages of
growth should be sacrificed by minimizing over-
feeding ofexpensive nutrients in the finisher phase.
In Table 9-9, the estimated changes in the balance
in which amino acids are required by growing pigs
with average lean growth potentials and with increas-
ing body weights are presented. It should be stressed
that these values are estimates and that these values
may change based on research that is currently in
progress.
198

217. In Tables 9-10 and 9-11, the suggested additions of
vitamins and minerals to practical grower and fin-
isher diets are summcrized. These suggested values
include a safety margin to account for inaccuracies in
feed preparation, variation in requirements for
different groups of pigs, loss ofpotency of vitamins
during storage, and the effect ofstress on require-
ments. Given these safety margins and the cost of
these nutrients, it is not critical to adjust these
suggested levels of fortification for specific groups
ofpigs. Exceptions may be made for breeding stock,
animals with extremely high lean growth potentials
(such as entire males) or when diets with extremely
high energy densities are fed. In these cases the
suggested additions may be increased by up to 20%.
Table 9-9. Estimated Change in the Balance in which
Amino Acids are Required by Growing Pigs with
Average Lean Growth Potentials and with Increasing
Body Weights.
Body Weight
30 kg 60 kg 90kg
Lysine 100* 100 100
Methionine 28 28 28
TSAA** 58 60 62
Threonine 62 65 67
Tryptophan 18 19 19
Isoleucine 62 62 61
* all values are expressed relative to lysine and as apparent
ileal amino acid digestibilities: derived from Fuller. M.F.,
R. McWilliam. T.C. Wang and L.R. Giles. 1989. Brit. J.
Nutr. 63:255-267; and Technisch Model Varkcnsvoeding
(TMV). 1994. Proefstation voor de Varkenshouderij,
Postbus 83, 5240 AB, Rosmalen, The Netherlands.
** Total Sulfer Amino Acids - Methionine+ Cystine.
Table 9-10. Recommendations for Vitamin Fortiflca-
tion ofGrower and Finisher Diets=.
Vitamin Units/kg Grower Finisher
Vitamin A IU 7000 5500
Vitamin D ru 700 550
Vitamin E IU 351
251
Vitamin B12 mcg 20 15
Vitamin C mg -2
-2
Vitamin K mg 2.5 2
Biotin mcg _3.4 _3,4
FolicAcid mg 04 04
Niacin mg 25 20
Pantothenic acid mg 20 15
Pyrodoxine mg 0 0
Riboflavin mg 5 4
Thiamine mg 0 0
Choline mg 0 0
'The values in this table are minimwn supplemental
quantities recommended for practical diets. Due to
varying conditions and the influence ofthe diet type on
vitamin requirements, deviations from these nwnbers may
be required in some circwnstances. In pigs with extremely
high performance levels, when pigs may be used as future
breeding stock, or when high nutrient dense diets are fed,
these levels may be increased by 10 - 20%.
'Higher levels (up to 200 IU/kg) of vitamin E in the
finishing diet have been shown to enhance meat quality;
higher levels ofvitamin Emay be required when unsatu-
rated fats are included in the diet (3 TU/kg additional
vitamin E per g/kg ofadditional linoleic acid is recom-
mended).
2
The pig's requirement for vitamin C remains unclear.
3
When large quantities of ingredients are used that contain
low quantities ofavailable biotin (barley-canola meal based
diets) than an inclusion of50 mcg/kg ofbiotin is recom-
mended.
"Bictin and folic acid should be included in diets for pigs
that may be used as future breeding stock (200 mcg/kg of
biotin and I .5 mg/kg of folic acid.
199

218. Table 9-11. Recommendations for Mineral Levels in Grower and Finisher Diets.
Vitamin Units Grower Finisher
Macromincrals - Total
Calcium
Phosphorus
Available Phosphorus
Sodium
Chloride
Potassium
Magnesium
Microrninerals - Supplemented
Iron
Copper
Zinc
Iodine
Selenium
% 0.70 0.60
% 0.60 0.50
% 0.25 0.20
% 0.15 0.15
% 0.18 0.18
% 0.35 0.35
% 0.05 0.05
mg/kg 701
501
mg/kg 151 JOI
mg/kg JOO' 901
mg/kg 0.30 0.20
mg/kg 0.30 0.30
*The values in thistableare minimum levels orsupplemented quantities recommended forpractical diets. Dueto varyingconditionsand
the influenceofdiettypeonmineral requirements. deviations from these numbers mayberequired in somecircumstances. In pigswith
extremely high performance levels, whenpigs maybeusedas future breedingstock, orwhen highnutrientdense dietsarefed theselevels
may be increased by 10 -20%.
I
Coppermaybe used as agrowth promotantat 125 mg/kg in thediet. Dueto interactions in theutilization ofcopper, zincand iron, the
levels ofiron and zincshould be raised byapproximately60 mg/kgwhencopperis includedatgrowthpromotinglevels.
Photo 9-2.
i
..........,
... �
,, '? �
-Y:
-<,,, '_.....
../
Modem feeder barns provide a climate controlled environment, designed for the confort of pigs as well as farm workers. A
proper environment is required iffeeder barn goals are to be achieved.
-=---��������������������������
200

219. Typical Diets
There are a wide variety ofoptions available to
feed growing-finishing pigs. Tables 9-12 and 9-13
present some alternative formulae for the various
types ofpigs.
Table 9-12 contains diets that might be used in
areas where barley and wheat are most available.
Table 9-13 offers typical diets for areas where corn is
the predominant grain.
Table 9-12. Examples of Growout Diets based on Wheat and Barley.
2 3 4 5 6
Ingredients, %
Wheat 50.00 50.00 60.00 55.35 60.00
Barley 73.23 23.10 21.70 7.50 16.72
Peas 20.00
Soybean meal - 47% 11.70 16.90 18.50 10.35 17.60
Soybean meal - 44% 11.8
Canola meal 10.00 10.00 7.40 9.00 9.30
Fat/oil 1.00 l.00 1.00 l.00 1.40
Lysine HCl 0.07 0.10 0.18
Threonine 0.10
Premix 4.00 4.00 4.00 4.00 4.00 4.00
Nutrients, minimum %
D.E., kcal/kg 3,100 3,100 3,250 3,350 3,350 3,350
Crude protein 17.2 18.3 19.9 21.l 20.6 18.5
Digestible lysine 0.73 0.73 0.78 0.84 0.84 0.84
Digestible methionine 0.20 0.20 0.22 0.23 0.23 0.23
Digestible TS.A.A. 0.42 0.42 0.47 0.52 0.52 0.52
Digestible threonine 0.45 0.45 0.51 0.56 0.56 0.56
Digestible Tryptophan 0.13 0.13 0.15 0.16 0.16 0.16
Calcium 0.75 0.75 0.75 0.75 0.75 0.75
Phosphorus 0.65 0.65 0.65 0.65 0.65 0.65
Sodium 0.15 0.15 0.15 0.15 0.15 0.15
Chloride 0.15 0.15 0.15 0.15 0.15 0.15
These are sample diets only and are for illustrative purposes only. While every attempt has been made to present exam-
pies that reflect successful commercial formulations, these examples are not intended for actual use without assistance
from a qualified nutritionist.
All amino acid concentrations arc expressed as apparent ilea! digestible amino acids.
201

220. Table 9-13. Examples of Growout Diets Based on Corn.
2 3 4 5
Ingredients, %
Corn 69.25 70.18 64.30 40.70 47.10
Wheat 30.00
Peas 25.00
Soybean meal - 47% 26.75 27.80 23.50 13.85
Soybean meal - 44% 24.65
Canola meal 7.50
Lysine HCI 0.10
Fat/oil 1.05 3.90 l.80 2.55
Threonine 0.02
Premix 4.0 4.0 4.0 4.0 4.0
Nutrients, minimum %
D.E., kcal/kg 3,440 3,450 3,650 3,500 3,500
Crude protein 18.60 17.00 18.70 18.67 19.30
Dig. lysine 0.84 0.79 0.86 0.79 0.79
Dig. methionine 0.23 0.22 0.24 0.22 0.22
Dig. T.S.A.A. 0.52 0.46 0.50 0.47 0.47
Dig. threonine 0.56 0.49 0.53 0.51 0.51
Dig. Tryptophan 0.16 0.14 0.15 0.15 0.15
Calcium 0.75 0.75 0.75 0.75 0.75
Phosphorus 0.65 0.65 0.65 0.65 0.65
Sodium 0.15 0.15 0.15 0.15 0.15
Chloride 0.15 0.15 0.15 0.15 0.15
These are sample diets only and are for illustrative purposes only. While every attempt bas been made to present exam-
pies that reflect successful commercial formulations, these examples are not intended for actual use without assistance
from a qualified nutritionist.
All amino acid concentrations are expressed as apparent ilea! digestible amino acids.
All diets will support a reasonable level of per-
formance. These formulations are examples only and
many other combinations are possible. Due to the many
factors that influence pig performance, results with these
diets may vary from fa11TI to farm.
These formulations are only samples. Exact
rations will depend on the 'actual' composition ofthe
ingredients on hand, which can be determined only
by having the feeds tested. Rations used on indi-
vidual farms may vary from these examples and
should be formulated by a qualified nutritionist.
202
Formulations employing commercial supplements
are not included in the tables because their nutrient
composition varies among suppliers. Combinations
ofgrains with supplements are possible and inter-
ested persons are encouraged to contact their feed
supplier for assistance to develop a balanced diet.
No one diet formulation will be the best for all
farms under all economic conditions. Flexibility is
the key to success in attaining the most value from
your feed dollar.

221. Feed Additives
A whole range offeed additives are available for
inclusion in feeder pig diets. They include enzymes,
acidifiers, probiotics, feed flavours, medications,
toxic binders, etc.. Many of these are discussed in
chapters three and eleven. Most ofthese additives
are more effective in diets for weaner and starter pigs
and for sows than in diets for feeder pigs. This can
be attributed to the relative maturity of the feeder
pig's digestive and immune system, and the lack of
sudden changes in levels of production and feed
intake (such as those around the time of farrowing).
The effectiveness offeed additives also differs
between individual production units, and in particular
with variation in the herd's health status and environ-
mental management. The average effects ofthe
various feed additives that are listed in Table 9 -14
may differ substantially from their effects on indi-
vidual pig production units. It is thus difficult to
make general statements about the cost-benefit
relationship ofeach of these feed additives. Produc-
ers that are considering the use ofvarious feed
additives are encouraged to demand "proof', or the
results of on-farm studies, from the suppliers ofthese
products. It should be noted that the use ofmany
feed additives, and ofmedications in particular, are
under govenment control and subject to the Feeds
Act (see also chapter 10).
A situation where feed additives may be particu-
larly effective is when feeder pigs are just moved into
the grower-finisher units, especially when pigs arc
commingled from different sources with varying
health status. In these situation, pigs should be fed
palatable, highly digestible diets that arc hightly
fortified with vitamins and minerals and contain
appropriate levels of feed medication. The use of
feed additives, such as acidifiers, may be considered
as well. A practical means to ease the adjustment to
the new environment is to feed a good quality pig
starter diet for the first week after the pigs have
arrived or until feed intake has increased to accept-
able levels.
It should be stressed that feed additives should not
be used to compensate for poor management and that
feed medication, at the allowed levels, will be inef-
fective in treating clinical levels ofdisease.
Phase Feeding
Various options are available for feeding growing-
finishing pigs. One option is phase feeding, in which
more than one diet is fed to pigs between their arrival
in the feeder barn and their attainment of market
weight. Phase feeding allows producers to meet the
pig's nutrient requirements more closely at its various
Table 9-14. Pig Response to Antimicrobials in Feed ofGrowing-finishing Pigs (16 kg to market weight) (adapted from
Zimmerman, 1986).
Number Wt(kg) AverageDaily Gain (g) Feed:Gain
Antimicrobial Exp Initial Final + %improve + %improve
CTC-P-S 7 25 92 738 787 6.6 3.16 3.11 1.8
Bacitracin MD 7 26 98 724 742 1.2 3.01 3.00 0.4
Bacitracin Zn I 31 100 695 695 0 3.36 3.42 -1.8
Chlortetracycline 17 27 94 694 717 3.3 3.23 3.23 0
CTC:P:ST 2 21 94 790 845 7.0 3.02 2.97 1.8
Coppersulfate 4 21 90 704 724 2.9 3.07 2.96 3.7
Bambermycin 30 37 94 669 687 2.7 3.48 3.36 3.4
Lincomycin 7 38 99 714 750 5.1 3.49 3.43 1.7
Nosiheptide 3 II 92 623 670 7.5 3.35 3.25 3.0
Salinomycin 9 17 94 735 779 6.0 3.05 2.94 3.7
Tiamulin 9 14 72 610 665 8.9 2.97 2.86 3.8
Tylosin 45 30 90 665 689 3.6 3.37 3.26 3.1
Virginiamycin 23 24 93 726 745 2.5 3.13 3.09 1.4
203

222. live body weights. For example, a diet with rela-
tively high DE and amino acid levels can be fed to
the grower pigs, and energy density and amino acid
levels can be reduced in the finishing diet. At the
same time, the supply of excessive nutrients can be
reduced when phase feeding is applied (see Figure 9-
9). It should be noted that a large proportion of feed
used in the feeder barn is consumed by the finishing
pigs. Based on a typical feed intake and growth
curve and a three phase feeding program, feed usage
between 25 and 45 kg body weight (grower I), 45
and 70 kg body weight (grower II) and 70 and I05
kg body weight (finisher) would be 18%, 27% and
55% of total feed usage, respectively. This implies
that close attention should be paid to the formulation
and cost of the finisher diet and that producers can
afford to invest in high, nutrient dense grower I diets.
Phase feeding requires the handling ofmore than
one feed in the feeder barn. The feed can be handled
in one of two ways: extra feed lines can move the
additional feed in bulk, or the pigs can be moved
from grower to finisher pens where they are fed
di:fferent diets. Phase feeding will increase the cost
offeed and/or animal handling but these additional
costs will be offset by the savings in feed cost.
According to the results in Table 9-15, the gross
margin per pig and gross margin per pig place per
year can be improved substantially when phase
feeding is applied. ln Table 9-15, gross margins
relate to carcass value minus feed cost, feeder pig
price, and variable cost per pig.
Table 9-15. Estimated Value of a One versus Two
versus Three Phase Feeding Program in Pigs with
Average Lean Grol, th Potential*.
Phase
One Two Three
Animal 12erfQrmance
Growth rate, g/d 0.772 0.784 0.789
Feed: Gain 3.28 3.24 3.22
Carcass index 106.20 106.30 106.30
Financial 12erformance
Feed cost, S/pig 38.44 37.03 35.89
Gross margin, $/pig 48.85 50.30 51.55
Gross margin, $/pig place/yr 156.23 163.14 168.16
*All diets contained 3150 kcal DE/kg. In the one phase
feeding program, one diet (available lysine .65%) was fed
from 25 to I 05 kg body weight. In the two phase feeding
program, Dietl (available lysine .70%) was fed from 25 to
60 kg body weight, and Diet II (available lysine .57%) was
fed from 60 kg to market weight. In the three phase feeding
program, Diet J (available lysine .75%) was fed from 25 to
45 kg body weight, Diet Il (available lysine .60%) was fed
from 45 to 75 kg body weight, Diet Ill (available lysine
.52%) was fed from 75 kgto market weight. The levels of
other amino acids and calcium and phosphorus were also
adjusted in the different diets. 1993 Saskatchewan prices.
Split-sex Feeding
Separate feeding ofsexes (barrows, gilts, entire
males) is an option that should be considered. Over
the last several years, a considerable amount of
information on the 'best' feeding regimes for
Table 9-J 6. Performance of Barrows and Gilts Fed a Similar Diet.
ex
Barrows Gilts
Initial weight, kg 23.9 24.4
Final weight, kg 105.1 104.1
Feed intake, kg/d 2.42 2.16
Gain, kg/d .84 .78
Feed: Gain 2.87 2.78
Dressing percentage, % 80.9 80.3
Carcass lean yield, % 48.1 50.5
Difference
+11%
+8%
+3%
+.7%
-5%
"Calculated as performance ofbarrows - gilts divided by the average performance ofthe two sexes.
** 1993 carcass grading system.
204
Source: Prairie Swine Centre Inc., I 993

223. barrows and gilts has been generated. As indicated
by the results in Table 9-16, barrows consume more
feed, grow faster, have poorer feed efficiency, and
lower carcass lean yields than gilts. Generally, the
differences in performance between these two sexes
increases as pigs grow heavier. Up to approximately
25 kg body weight, identifying any differences in
performance between gilts and barrows is difficult,
but differences in feed intake and growth rate may be
as high as 15% during the finishing phase of
production. This is illustrated by the feed intake
curves for Prairie Swine Centre barrows and gilts that
are presented in Figure 9-10.
2.8 •• • •••• • ••• • • ••••••• • • •• • •••••••••••• • ••••• • • ••• • ••• • •
':S --··---- ...
!
I �i::::::_.--..-·.:.--·.-� : --·····::::::::::1.4 • _•••• ••••••••••••••••• • • •• • •• • ••••• • • •• • • •••••••• • ••• • •
1.2.---�-�-�-�---�-�----<
20 30 40 so 60 70 80 90 100
Live body weight (kg)
- Barrows -·Gilts
Figure 9-10. Feed Intake Curves of Barrows and Gilts
Fed a Similar Diet and Housed in Groups of 12 Pigs
per Pen*.
*The DE content of the diet was 3250 kCal/kg; the DE
intake (cal/d) as a function oflive body weight (W) was
best described as 1747 x W089
for barrows and 1588 x
W090
for barrows and gilts, respectively.
Managing barrows and gilts separately means that
the two sexes can be fed different diets. Because of
their lower feed intake and higher lean growth rate,
gilts require higher levels ofamino acids and other
nutrients than barrows. Amino acid levels, or amino
acid to energy ratios, should be approximately 5%
and 15% higher in the gilts grower and finisher
diets, respectively. These numbers are supported by
observations from a large scale American study in
which the optimum dietary lysine levels were deter-
mined for gilts and barrows (Table 9-17). Gilts also
respond more favourably to increases in dietary
energy density. Producers may consider feeding gilts
diets that have higher DE content than those for
barrows, and maintaining the higher energy density
diets up to higher body weights. On the other hand,
the daily feed allowance for barrows may be reduced
in the finishing phase during which barrows deposit
large quantities of body fat. This reduction wiII
improve feed efficiency and carcass value slightly. If
you choose split-sex feeding as a feed option in your
operation, keep in mind that difference in perform-
ance between the two sexes, and thus the optimum
feeding strategy, may vary somewhat with the differ-
ent pig breeds and genotypes. Monitoring feed
intake and performance in the two sexes is important
whenever split-sex feeding is applied.
Table 9-17. Effect of Sex and Dietary Lysine Level on
Performance in Finishing Pigs (50.7 to 104.6 kg Body
Weight; NCR-42 Committee on Swine Nutrition 1993)
Dietary lysine level(%)
.60 .67 .74 .82
Barrows
Growth Rate, kg/d .817 .834 .828 .839
Feed Intake, kg/d 2.91 2.99 2.93 2.96
Feed: Gain 3.56 3.54 3.46 3.46
Lean Growth, g/d 306 315 313 320
Gilts
Growth Rate, kg/d .738 .781 .777 .779
Feed Intake, kg/d 2.59 2.63 2.59 2.58
Feed: Gain 3.52 3.35 3.32 3.27
Lean Growth, g/d 299 321 322 334
Photo 9-3.
The use ofseparate diets for Stage I (20 - 60 kg) and II (60 -
105 kg) growers is one �a) to improve efficiency. Providing
diets that are specific for each class ofpigs helps to maximize
productivity without wasting expensive nutrients.
205

224. Feeding Management Options Specifically
for Gilts and Castrates
* Feeding higher lysine diets to gilts than to
barrows. Gilts arc better at converting protein into
lean tissue than castrates, therefore the concept of
feeding to need will maximize the return per dollar
invested in feed.
* Feeding diets with a higher energy density to
gilts than to barrows, especially in the finishing
phase. In gilts, energy intake will limit lean growth
up to higher body weights than in barrows.
* Slaughtering castrates at a lighter weight than
gilts. Because gilts are leaner, carcass grades can
be maintained at heavier weights. Barrows tend to
deposit fat sooner and faster, therefore should be
marketed at a lighter weight.
* Feeding a different daily feed allowance to each
sex. Barrows' feed intake can be restricted to reduce
the deposit ofexcessive fat in the carcass. Barrows
grow faster than gilts but they also lay down fat
more quickly.
An additional advantage ofmanaging the two
sexes separately is that barn space will be used more
efficiently. Because barrows grow faster than gilts.
growth rates within pens will be more uniform when
the two sexes are kept separately. The barrow pens
will empty more quickly so can be turned over faster
than the gilt pens. As a result, more pigs can be
produced per year using the same amount of space
when split-sex feeding is utilized.
The benefits ofsplit-sex feeding will be increased
when entire males, rather than barrows, are used in
commercial pork production. In North America,
entire males cannot (yet) be used for pork
production. This situation may change as more
information becomes available about the factors that
cause the strong, adverse smell (boar taint) in some
206
Photo 9-4.
There is no doubt that in the future barrows and gilts will be
fed separatley, some producers are already doing so.
meat derived from entire male pigs. Lean growth
potential are higher in entire males than in gilts.
Entire males require more nutrient-dense diets but
can utilize these diets more efficiently than gilts.
Feeding to Appetite Versus Restricted
Feeding
Most pigs in Canada are fed to appetite, which
means they are given continuous access to feed. The
objective ofthis feeding method is to maximize feed
intake, thus growth rate. There are several benefits to
feeding to appetite. Carcass merit will suffer
somewhat when pigs are fed to appetite, but the
reduced value ofa slightly fatter carcass is thought to
be more than off-set by a faster growth rate. Ad
libitum feeding is more easily automated than
restricted feeding so that labour costs are lower.
Restricted feeding also has benefits, the major one
being that feed efficiency and carcass value may
improve and growth rates may be reduced when feed
intake is reduced (see Figure 9-7).
The results in Table 9-18 indicate that feed intake
should be maximized when the production objective
is to maximize income per pig place per year. Yet, a
l0% reduction in feed intake is expected to increase
the income per pig. Efforts to improve carcass
quality in Canada have been directed largely al
genetic selection and diet formulation. As the lean
growth potential ofpigs continue to increase due to
genetic selection and improvements in health status,
the potential benefits ofrestricted feeding will
decline.

225. Level of feed intake Average* Average - 10%
feeder pigs were allowed continuous access to two
feeders with different feeds. One diet was formu-
lated to contain high levels of available nutrients to
meet the highest possible nutrient requirements of
any pig in the pen. The second diet was formulated
with low available nutrient levels to meet the require-
ments ofthe pig with the lowest possible nutrient
requirements. The theory tested was that each pig
would adjust its consumption ofthe two diets to meet
its nutrient requirements. Gilts would consume more
ofthe high nutrient diet than barrows, and all the pigs
would consume relatively more ofthe low nutrient
diet as they grew heavier and required fewer nutrients
per kg of feed. Unfortunately, the observations in
many studies were different from the expectations.
The pigs tended to over-consume on the more expen-
sive hizh nutrient dense diet. Plus, the choice of' 0
diets was affected by the presence ofsmall quantities
ofunpalatable ingredients in both diets. Clearly,
more research is needed before choice feeding can be
applied to commercial pork production units.
*Upper limit to lean growth is approximately 350 g/d.
Average feed intake is considered 90% of voluntary fe�d
intake according to NRC 1987. 1993 Saskatchewan prices.
Table 9-18. Estimated Effect of Level of Feed Intake on
Animal and Financial Performance in Pigs with a
Slightly Better than Average Lean Growth Potential*.
Growth rate, g/d 823.00 729.00
Feed: Gain 2.97 2.88
Carcass dressing % 79.70 79.20
Carcass index 107.80 110.30
Gross margin per pig($) 30.22 31.42
Gross margin
per pig place per year($) 98.50 92.50
Limit feeding systems must be carefully managed
and controlled to maximize the benefits and mini-
mize the loss in growth rate. A recommended
feeding scale for Canada has not been developed.
However, if carcass improvement through dietary
manipulation is desired, the best approach is to
progressively restrict feed intake (as a percentage of
ad libitum) as the pigs approach market weight.
Early restriction (under 60 kg body weight) offers
little benefit. Feed intake should not fall below 80%
of voluntary feed intake, according to NRC (1987),
or growth rate will be seriously impaired. An addi-
tional disadvantage of(severe) feed intake restriction
is that the variation offeed intake between pigs
within pens will increase and, as a result, variation in
growth rates may increase. The incidence ofpigs
doing poorly may increase when feed intake is
restricted too severely.
Choice Feeding
Whenever phase feeding or split-sex feeding is
applied in the feeder barn, various diets are needed to
meet each group ofpigs' specific nutrient require-
ments. One way to reduce the need for different
diets and diet changes is to allow the pigs to make
their own choice of feed and quantity they want to
eat. Various studies have been conducted in which
Feeding of Pigs Housed Outdoors
Due to the high cost ofconstructing new facilities,
there has been a renewed interest in low-cost, alterna-
tive outdoor housing systems for growing-finishing
pigs. Initial experience at the University ofManitoba
suggests that during the summer months. pig per-
formance in a low-cost housing system is nearly
similar to that ofpigs in a conventional feeder barn
(Table 9-19). However, in the fall and winter
months, feed efficiency is substantially poorer in the
pigs housed in the low-cost, outdoor system. The
differences in feed efficiency in the fall and winter
were 12% and 21%, respectively. Obviously, addi-
tional feed cost should be weighed against the
reduction in construction and operating costs when
these low-cost facilities are considered.
No actual studies have been conducted to deter-
mine the nutrient requirements for pigs raised out-
doors under Canadian conditions. However, the
difference in performance between outdoor and
indoor raised pigs during the fall and winter months
was due primarily to differences in feed intake.
Differences in feed efficiency can be largely attrib-
uted to differences in energy required to maintain a
constant body temperature. This difference in energy
requirement means that the levels ofamino acids,
vitamins, and minerals can be reduced in the diets
that are fed to the outdoor pigs in the fall and winter
207

226. months because they are consuming more feed.
Based on the observations at the University of
Manitoba, the dietary levels of amino acids, vitamins
and minerals may be reduced by approximately 8
and 15% during the fall and winter months, respec-
tively, as compared with diets for pigs housed in
conventional indoor facilities. Despite the reduction
in the dietary levels, the daily allowance ofthese
nutrients should still be maintained somewhat higher
to account for the larger variation in feed intake and
feed wastage in pigs that are housed outside in large
groups.
Feed Separation
Feed separation was discussed in detail in chapter
5. Table 9-20 summarizes the results ofa Swedish
study reported by Dr. Ove Olsson. The study looked
at three feed handling systems: I) mixed feed added
directly to 50 kg bags, 2) bulk feed with careful
handling, and 3) bulk feed with ordinary handling.
Study results show that separation decreased uniform
growth and feed efficiency. Separation is a problem
that costs money and should receive much more
attention than it does.
Photo 9-5.
Since corrosion is a major problem in feeder construction,
concrete, plastic, or stainless steel feeders are becoming much
more popular in free choice systems.
208
Trial 1
Shelter
# ofpigs 175
Initial weight, kg 23.9
FinaJ weight, kg 100.80
Feed intake, kg/d 3.05
Weight gain, kg/d 0.90
Feed/gain 3.39
Carcass index 103.70
Trial 2
Shelter
# of pigs 177
Initial weight, kg 32.50
Final weight, kg 101.00
Feed intake, kg/d 3.38
Weight gain, kg/d 0.92
Feed/gain 3.67
Carcass index 103.20
Trial 3
Shelter
# ofpigs 178
Initial weight, kg 31.7
Final weight, kg 100.5
Feed intake, kg/d 3.62
Weight gain, kg/d 0.90
Feed/gain 4.02
Carcass index 103.40
Conventional
150
28.20
I 01.00
2.98
0.92
3.24
103.60
Conventional
150
34.10
100.80
2.92
0.89
3.28
102.80
Conventional
150
32.3
101.1
3.19
0.96
3.32
103.0
Table 9-19. Performance Data Comparing Shelter and
Conventionally Raised Feeder Pigs During the
Summer {May through August, Trial 1), Fall (August
through November, Trial 2) and Winter (November
through February, Trial 3). (University of Manitoba,
Courtesy of Dr. Connor)
In the system that was evaluated at the University of
Manitoba, approximately I 75 pigs were housed in one
large group in a quonset-shaped structure, 9.15 x 21.96 m,
with the ends opened during most of the year. Pigs were
fed from a large 5 tonne feeder and two waterers were
present on a cement pad at one end of the shelter. Deep
litter straw was present in the remaining area.

227. Table 9-20. Effect of Feed Handling on Pig Performance.
No. of pigs
Initial weight, kg
Final weight, kg
Average daily gain, kg
Variation in weight gain1
Feed efficiency
I Standard deviation for growth rate.
Feed Wastage
There is a growing misconception that feed wast-
age is an over-rated concern. Feed wastage is very
difficult to measure but given the design offeeders in
use, the frequency (or Jack) ofadjustments, and the
nature ofcurrent housing systems, it is apparent that
wastage is still a problem to be addressed. Perhaps a
more accurate picture ofwastage would be painted if
feed utilization was referred to as 'feed disappear-
ance' rather than 'feed intake'.
Feed disappearance includes the feed that is wasted
as well as the feed that is eaten. The producer pays
for the total feed disappearance, notjust the feed that
is eaten. The difference in terminology is important.
Differences in feed conversion of 10% can result
solely from controlling feed wastage. According to
farm surveys, that 10% can be worth as much as five
to six dollars per pig. Controlling excessive wastage
is probably the easiest money a farmer will ever
make. An important point to consider is proper care
and maintenance ofthe feeders. Buying the right
type offeeder will make the job much easier as will
care in selecting and positioning feeder adjustments
that provide the pigs easy access to feed without
wastage.
Feed wastage is particularly high when pigs are
floor fed. Results from British studies (Table 9-21)
clearly demonstrate that, even when feed intake in
F��d Handling S::tst�m
I n Ul
Careful Normal
Bagged Bulk Handling Bulk Handling
24 24 24
20.500 20.500 20.500
97.000 96.000 96.300
0.580 0.560 0.550
0.030 0.038 0.042
3.310 3.440 3.550
floor fed pigs is restricted to reduce feed wastage,
performance of floor fed pigs is poorer than those
given the same amount of feed through feeders.
From these results it can be estimated that feed
wastage was approximately 5.5% higher for the floor
fed pigs. This increase in feed wastage, in combina-
tion with the improvements in performance ofpigs
that are fed ad libitum through feeders, will quickly
pay back for the investment in feeders.
Table 9-21. Effect of Floor Feeding on Growing-
finishing Pig Performance (33 to 88 kg body weight).
Floor Feeder feeding
Feeding Restricted Adlib
Feed Disappearance" 2.12 2.11 2.21
Gain (kg/d) 0.74 0.77 0.81
Feed:Gain 2.89 2.74 2.78
*(kg/d) includes feed wastage
Derived from Patterson. D.C. 1989. Anim. Feed Sci.
Techn. 26: 251-260.
Feed form and feed processing are also related to
feed wastage. As illustrated by the results in Table 9-
22, feed efficiency is approximately 8% better in
209

228. Feed Disappearance (kg/d)* 2.29 2.17
Feed form
Pellets Meal
*includes feed wastage
Derived from Walker. N. 1990; Pig News and Information
Vol. ll(l)pp.31-33.
Table 9-22. The Effect of Feed Form on Performance
of ad libitum Fed Pigs (35 to 87 kg body weight;
combined results of various studies; approximately
1000 pigs per treatment).
minimal labour, provides extremely useful
information.
The importance of good financial and production
records is well established. The computer has helped
many of us monitor cash flow, animal flow, and
production in a very sophisticated manner. One note
ofcaution: records from a computer are only as
correct as the information entered into it and are only
as accurate as the program being used. Anyone using
a program should learn how the calculations are
made so he or she knows how the final numbers are
produced. Very often the summaries make important
assumptions that can influence how the data is to be
interpreted. Ifunaware ofthese assumptions, a
producer may misunderstand the information and
make unsound management decisions. Companies
offering record keeping systems are generally more
than willing to provide assistance in this regard.
Compare your computer summaries with 'real'
data. For example, if the computer says you are
weaning 21 pigs per sow per year and you have a
herd of I 00 sows, are you really weaning 2100 pigs
per year? Checks like this one will give you greater
confidence in your computer results.
A computer is not necessary to keep records,
though. Ifthe number ofpigs in a barn is reasonably
constant, you can estimate the days to market by
measuring the rate of inventory turnover (ifthe
number ofpigs in the barn fluctuates too much, the
results will be misleading). To measure inventory
turnover, you must know the average number ofpigs
on the farm throughout the year and the number of
pigs sold per year, including gilts raised as replace-
ment breeding stock (see Table 9-23). Month-end
inventories including nursing pigs, and weanling and
market hogs can be used for the calculation. Do not
include the breeding herd in your calculation.
Surveys have shown that the average number of
'days to market' is close to 200 days. The experi-
ence of some commercial producers, however,
indicates that 165 days for pigs to reach I 05 kg is a
realistic management objective. Better performance
( 140 - 150 days) is possible with careful manage-
ment, all-in all-out housing, healthy stock, excellent
diets. and maybe just a bit of luck! The data summa-
rized in Table 9-23 demonstrates that the average
number ofdays to market below 150 is possible
under commercial conditions.
0.78
2.82
0.75
3.06
Grun (kg/d)
Feed:Gain
pigs fed pelleted feeds as compared to pigs fed the
same diet but in a meal form. As there is little effect
of pelleting on the digestibility ofnutrients by
grower-finisher pigs (as is the case in starter pigs),
the difference in performance can largely be attrib-
uted to feed wastage. This implies that the effect of
feed pelleting on feeder pig performance will depend
on feeder design and feeder management; it will be
smaller when feeders are well managed and when
feed wastage is already minimal. For further discus-
sions on feed processing see chapter I 0.
Monitoring Performance
Once the 'correct' feeding regime has been se-
lected, it must be maintained. Performance must be
monitored to see if goals are being achieved. Ifgoals
are consistently not being achieved, solutions to
existing problems must be found. Ifgoals are being
met, they should be re-evaluated and new ones set. If
the goal is to maximize profit per pig, changes in
feed prices relative to the price of pork may require
adjustments in the feeding program. If the objective
in developing feeding programs is to meet the ani-
mals' nutrient requirements as closely as possible,
nutrient levels in the feed should be adjusted with
changes in observed levels of feed intake.
Monitoring feeder barn productivity is a very
worthwhile activity. Full record keeping systems are
more compI icatcd than those in the breeding and
farrowing areas and may be daunting at first. Some
type of monitoring, however, is important - even
spot-checking ofdays-to-market or recording feed
conversion on the odd random pen, which requires
210

229. Table 9-23. Calculation of Days to Market Based on Inventory Turnover.
Item l 2 3 4 5
Erem RecQrds
Avg. Inventory 325 3215 1256 1230 698
# of Pigs Sold/Year 728 5883 2135 3038 1459
Calculated
Inventory Turnover 2.24 1.83 1.70 2.47 2.09
Avg. Days to Market 163 199 215 148 175
Inventory turnover= number ofpigs sold per year - by average inventory.
Average days to market = 365 days in the year - by inventory turnover.
Photo 9-6a.
Photo 9-6b.
Feeders need to be adjusted very carefully to avoid wastage
due to spill, but also to ensure continuous access to feed. The
top (9-6a) feeder is well adjusted, generating little waste.
The bottom (9-6b) feeder is acceptable, although some
sections may be difficult to eat from.
The feed conversion in a feeder barn can be
estimated ifyou know how much feed entered the
barn during the year. This amount is determined by
measuring the feed inventory at the beginning ofthe
year; adding all purchases made during the year, then
subtracting the year-end inventory. This calculation
is much easier ifyou purchase all your feed but can
also be used for the total farm ifspecific amounts of
feed cannot be assigned to individual barns. The
following example can be used for a feeder barn
only:
Feed disappearance= 545.7 tonnes/year
= 545,700 kg/year
Amount ofpork sold= 161.673 kg/year
(from marketing statements)
Live weight sold - 161,673 - 0.79
= 204,650 kg
(79% dressing percent)
Pigs weigh an average of 20 kilograms on entering
the feeder barn. Therefore, the total weight gain
within the feeder barn will be:
211

230. Feed Intake Curuc
Figure 9-lla and 9-llb. Estimated Feed Intake and
Growth Curves Derived from a Limited Number of De-
tailed Observations on Feed Intake and Body Weights
in a Feeder Barn.
e
e
d
(
k
n
t
•k
y
)
g
h
t
B
Q
d
y
(
k
..................... II
/
d
89 '8 109 110
i ;,,, ; ·-··--� .
i r
I
'18 60 72 111 'J6 108 120
0..ys In the Born
: I : :
• Obscrucd Do.ta
•• Fitted - Curuoc
• Obserued !Jat.a
• • fl tted Intake Curue
- Standard lntalce Curuo <NRCl
Obserued Lluo Bocly Weight Ckgl
An 1... 1 Grouth Cw-uc
60.0
35.8
85.8
:
.-·---·,:-···'· -f i l,r":.,,..,,. ··--00!---•·•-•••,•••••·•···•-:·• f
l »:" .l-- l I ! i
, /,·; s, ·l-··-··-i···- "j1
i
·------!--··-·'t',
=
- :.! .
..... i : :
i !
!
10.e�---'----------------�
9 12 21 36
3.0
z.8
··········.·····
LO •
1.0,--------------------.
ciency is required to estimate feed cost per pig. The
marginal feed efficiency is required to determine the
optimum shipping weight, i.e., the increase in feed cost
to raise pigs to heavier weights. For the development
ofa multi-phase feeding program, the estimated levels
of feed intakes can be used to determine the optimum
dietary nutrient levels in diets ateach individual phase.
Prairie Swine Centre Inc. has created a computerized
performance monitoring system that allows for the de-
velopment ofa feed intake and growth curve based on
a limited number ofdetailed observations on a selected
number ofpens. The program can also be used to esti-
mate feed cost and gross margins per pig or per pig
place per year.
8.8'--------'------'---'--...;.__...___
18 ze se i8 se 60 ?e
Once a reliable system for monitoring herd perform-
ance has been established. the success or failure ofcur-
rent management methods can be evaluated. Plus, the
benefits ofany changes made in management practices
can be assessed on the basis of actual measurements
taken.
110.9,----------------��
r.> •
Total weight gain= 204,650 - (2025 weanling x
20 kg/weanling)= 164,150 kg
Feed conversion= 545,700 kg feed/year -
164, 150 kg weight gain in the feeder barn
- 3.32 kg feed/kg gain
The major disadvantages of inventory-based
performance monitoring systemsare that they do not
provide information on uniformity ofgrowth and
flow ofpigs through the barn and on performance at
the various stages ofgrowth. Since highly variable
growth rates among pigs leads to reduced barn
utilization, many producers use individual animal
tattoos to monitor average and ranges ofdays to
market. Ifthere is too much variation in starting and
ending inventories, estimated feed efficiency can also
be badly skewed. Records should be collected over
at least a three month period, and more likely over a
six month period, before performance can be esti-
mated with reasonable accuracy.
An alternative to these inventory-based record
keeping systems is to accurately monitor perform-
ance in a limited nwnber ofrepresentative pens in the
growing-finishing barn. Based on feed usage and
body weight gain in the monitor pens, performance
in the rest ofthe barn can be estimated. Iffeed
disappearance and body weight gain is monitored at
regular intervals, complete feed intake and growth
curves can also be developed.
The feed intake and growth curves, presented in fig-
ures 9-11 a and 9-1 lb, are derived from observations
on six different pens over a 14 day period. Observa-
tions were recorded for feed intake (based on feed dis-
appearance and feed wastage), average body weight,
and the number ofdays the pigs are in the barn. These
curves provide information on animal performance at
each stage of production. For example, the informa-
tion on feed intake, growth rate, and feed efficiency
summarized in Table 9-24 is derived from the feed in-
take and growth curves presented in Figure 9-11. The
data in Table 9-24 indicate that the overall feed effi-
ciency between 25 and 105 kg body weight is 2.95 in
this particular growing-finishing barn. However, the
marginal feed efficiency, the amount of feed required
to produce the last kg ofbody weight, is 3.95 between
l00 and 105 kg body weight. The overall feed effi-
212

231. Table 9-24. Estimated Performance of Feeder Pigs Based on Feed Intake and Growth Curves Presented in
Figure 9-11.
Wt. Range Marg. Cumm. Feed Int. MargGain Cum. Gain Marg.FCE Cum. FCE
(kg) Days Days (kg/day) (g/day) (g/day) (g/g) (gig)
25 - 30 8.0 8.0 1.475 628.4 628.4 2.35 2.35
30- 35 7.3 15.3 1.671 682.4 654.3 2.45 2.40
35 - 40 6.9 22.2 1.868 727.9 677.1 2.57 2.45
40-45 6.5 28.7 2.034 766.0 697.3 2.66 2.50
45 - 50 6.3 35.0 2.184 797.5 715.3 2.74 2.55
50 - 55 6.1 41.0 2.322 823.1 731.3 2.82 2.60
55 - 60 5.9 47.0 2.447 843.5 745.4 2.90 2.64
60- 65 5.8 52.8 2.562 859.0 758.0 2.98 2.68
65 - 70 5.7 58.5 2.666 870.2 769.0 3.06 2.73
70- 75 5.7 64.2 2.762 877.1 778.6 3.15 2.77
75 - 80 5.7 69.9 2.848 880.3 786.9 3.24 2.81
80- 85 5.7 75.6 2.927 879.9 793.8 3.33 2.85
85 - 90 5.7 81.3 3.000 876.1 799.6 3.42 2.90
90-95 5.8 87.0 3.066 869.2 804.2 3.53 2.94
95 - I 00 5.8 92.9 3.126 859.2 807.7 3.64 2.99
100 - 102 2.4 95.2 3.164 850.5 808.7 3.72 3.01
Meat Quality
Meat quality is not valued in the Canadian price set-
tlement system for pig carcasses. The relative carcass
value is determined based on dressed carcass weight
and the estimated lean yield in the carcass (Table 9-2).
Thus, there is no direct benefit for pork producers to
produce pig carcasses with superiormeat quality. How-
ever, the profitability ofthe meat packer, andindirectly
that ofthe pork producer, will be affected by the qual-
ity ofthe pork products that are sold. Many aspects of
meat quality, such as the incidence of pale, soft and
exudative (PSE) pork, are affected primarily by pig
genotype and the handling ofpigs just prior to slaugh-
ter. Attempts to reduce the incidence of PSE in pork
via manipulation ofthe composition ofthe pre-slaugh-
ter diet have been largely unsuccessful.
One aspect of meat quality, the quality of intra- and
extra-muscular fat, can be manipulated by the diet com-
position. As more unsaturated fat is included in the
finishing pig diet, carcass fat becomes softer and more
prone to oxidation or rancidity. This condition can af-
fect shelf-life and consumer acceptance of fresh pork
products. If the total fat content of the finishing diet
exceeds 4.5%, more saturated fats, such as tallow,
should be chosen over vegetable oils, such as soybean
or canola oil.
Some other dietary nutrients have been related to
various aspects of meat quality, most noticeably vita-
min E. Several studies with beef, and a limited number
ofstudies with pigs, have demonstrated that, when up
to 200 IU/kg ofvitamin E are included in the dietjust
prior to slaughter, meat colour in fresh meat products
can be maintained longer and drip losses can be re-
duced.
Other Management Considerations
As previously discussed, feed cannot be considered
in a vacuum. It must be viewed as part ofa total man-
agement package.
Floor space per pig is important. It not only influ-
ences productivity, but also the pigs' health, behaviour,
and well-being. Table 9-25 summarizes floor space
guidelines for the feeder barn that were suggested in
the Recommended Code ofPracticefor the Care and
Handling ofFarm Animals recently published by Ag-
riculture Canada. These values are not absolute, but
are useful estimates ofthe space allowances for feeder
pigs. There is a very fine line between reducing the
space per pig to expand the barn population, and over-
crowding causing the barn throughput to suffer. Other
factors, such as pen size, the number of pigs per pen,
213

232. feeder design, and location, will also affect space re-
quirements and performance ofgrowing-finishing pigs.
If 15 finishing pigs are grouped in one pen, a pen size
of4.3 m x 2.3 mis suggested. This size is based on the
amount of space required according to the Canadian
code ofpractice to accommodate 15 pigs at 95 kg body
weight. Given variations in animal performance, the
first pig is already shipped from the pen when the av-
erage body weight ofall pigs in the pen reaches 95 kg.
Controlling the barn temperature is also an impor-
tant practice. The effective barn temperature, which is
the combined effect ofmany factors, including air tem-
perature, air speed, air humidity, floor type, dryness of
floor, and the pig's body condition, all have a direct
effect on feed intake and animaJ performance. If the
effective environmental temperature is too cold, extra
feed is required to maintain a constant body tempera-
ture and feed intake will increase. If, on the other hand,
the effective environmental temperature is too hot, feed
intake will quickly reduce and growth rates will de-
cline. The optimum temperature range, i.e., the tem-
perature range in which pigs are neither too hot nor too
cold, is relatively narrow, and will reduce with increases
in live body weight. It is recommended that barn tem-
peratures do not fall below 18 - 20°C for growing pigs.
Lower temperatures (l2°C) may be acceptable in all-
in, all-out barns when the pigs in a given room reach
75 kg ofbody weight. As pigs approach marketweight,
a barn temperature of 12°C is quite acceptable if the
pigs are dry and free ofdrafts.
Other housing recommendations include the provi-
sion of one waterer for every 15 pigs. The scientific
basis for this recommendation is limited, so it should
be interpreted as a useful guideline only. Water quality
and water flow rates should be monitored regularly. It
is recommended that the flow rate for growing-finish-
ing pigs be between 1.0 and 1.5 litres per minute (0.22-
0.33 imperial gallon per minute). Consult the manu-
facturer's recommendations for optimum watererplace-
ment.
214
Table 9-25. Recommeded Pen Floor Space Allowances
for Growing Pigs*
Body weight Fully slatted Partial slats
kg (lb) m2 (sq ft) m2 (sq ft)
25 (55) .30 (3.2) .33 (3.6)
50 ( 110) .48 (5.2) .53 (5.7)
75 (165) .62 (6.7) .70 (7.5)
100 (220) .76 (8.2) .85 (9.1)
*Recommended Code of Practice for the Care and Handling
ofFann Animals
Additional Reading and References
Agriculture and Agri-Food Canada Publicaiton 1898/
E. 1993. Recommended code ofpractice for the care
and handling offarm animals - pigs. Communication
Branch, Agriculture Canada, Ottawa, ON, Canada.
Veterinary Infectious Disease Organization. 1987.
FeederBarn Design and Management. Saskatoon, Sas-
katchewan. 48 pp.
Forbes, J.M., M.A. Varley and T.L.J. Lawrence (Ed.).
1989. The voluntary food intake ofpigs. Occasional
publication of the British Society of Animal Produc-
tion. P.O. Box 3, Penicuik, Midlothian Eh26 ORZ,
Scotland.
Midwest Plan Service. 1983. Swine Housing and
Equipment Handbook. Iowa State University, Ames,
IA. 112 pp.
Miller, E.R., D.E. Ullrey and A.J. Lewis (Ed.). 1991.
Swine Nutrition. Butterworth-Heinemann, 80
Montvale Avenue, Stoneham. MA 02180, USA. pp.
1-673.
Moughan, P.J., M.W.A. Verstegen and M.I. Visser-
Reyneveld (Ed.). 1995. Modelling growth in the pig.
EAPP publication No. 78. Wageningcn Pers, P.O. Box
42, 6700 AA Wageningen, The Netherlands.
English, P.R., V.R. Fowler, S.Baxter and B. Smith.
1988. The Growing and Finishing Pig - Improving
Efficiency. Farming Press, Ipswich. 555 pp.
Zhang, Y. 1994. Swine building ventilation - a guide
for confinement swine housing in cold climates. Prai-
rie Swine Centre Inc. Saskatoon.

233. 10. DIET PROCESSING AND DELIVERY
Processing and delivery of feed to pigs is obvi-
ously a critical part of pork production. Whether
feeds are prepared at a commercial feed mill or
mixed on the farm, proper processing and delivery
are absolutely essential to achieving high quality,
consistent feed mixtures for pig consumption.
Poorly processed feeds result in impaired feed
utilization, poor performance and in some instances,
serious health problems. Understanding the nature
offeed processing, the reasoning behind each
procedure and the needs ofthe pig are important to
all pork producers, whether they buy prepared feeds
or manufacture their own diets on the farm.
There are several reasons for processing diets
before feeding them to swine:
1. To alter the physical form or particle size.
For example, grains are ground to reduce particle
size and thus improve their compatibility with
other ingredients in the diet.
2. To improve nutrient availability. All grains
must be ground before being fed to swine if
nutrient availability is to be maximized. Studies
at the University ofAlberta found that lysine is
12% more available to the pig from ground
wheat as compared to rolled wheat. The average
improvement in availability ofall essential amino
acids is more than 6%. Pelleting and extruding
are also processes used to improve nutrient
availability.
Photo 10-1.
A modern commercial feed plant.
Photo courtesy of Federated Co-operatives Ltd.
215
3. To isolate specific parts of an ingredient.
For example, oat hulls can be separated from oats
to produce oat groats for use in starter diets. The
remaining oat hulls can be used in gestating sow
or cattle diets.
4. To improve handling. The objective of feed
processing is to create a feed mixture that flows
freely and does not separate. In some cases
producers may wish to increase bulk density to
reduce storage and hauling costs. For example,
pelleting has been found to increase the bulk
density ofwheat shorts by 80%. Bulkiness of the
feedstuffcan also reduce feed intake. By increas-
ing the physical density ofthe diet, daily nutrient
intake can be improved. For example, gut
capacity often limits the quantity of feed con-
sumed by the young pig. Therefore, physical
density of the feed will influence the young pig's
nutrient intake.
5. To improve palatability. Mixing unpalat-
able, but necessary ingredients with those that are
more appealing to the pig, increases the intake of
required nutrients over the amount that would be
eaten ifingredients were offered individually.
6. To preserve. Drying or treating high mois-
ture grains with organic acids improves the length
oftime they can be stored.
7. To detoxify. Cleaning removes undesirable
weed seeds that may prove to be toxic to the pig.
Researchers are currently looking at chemical
detoxicants as a way to improve the feeding
value of moldy grains.
8. To create a uniform final feed mixture.
This is particularly critical in feeds for young
pigs, who eat relatively small quantities offeed
per day. However, a proper feed mixture is
necessary for all classes ofswine to ensure that
they achieve maximum performance. Research
has shown that pigs do not possess "nutritional
wisdom" to the extent that they will consume a
properly balanced diet. They will seek out
certain nutrients such as salt if required, but they
are incapable ofbalancing a complete diet. For
this reason, a nutritionally balanced mixed feed
must be offered to pigs. Jf the feed is not uni-
form, daily nutrient intake could fall below
requirement and thus impair performance.

234. A large number ofprocessing methods are avail-
able to the swine industry. They include mixing,
grinding, rolling, cracking, popping, extruding,
micronizing (pulverizing), roasting, dry pelleting,
steam pelleting, steam rolling and reconstituting. In
practice, only a few, including mixing, grinding,
extruding and steam pelleting, are commonly used.
The selection ofone or more processes will depend
on the ingredients employed, the age ofthe pig
being fed and the cost/benefit relationship.
Table 10-1. Effect of Fineness ofGrind on the
Performance ofWeanling Pigs Fed Barley-based Diets.
Screen size, mm 3.2 4.8 Difference
Particle size.urn 634 767
Daily gain, g 386 367 +5.2%
Daily feed, g 653 653 nil
Feed:gain l.70 1.79 +5.0%
Source: Adapted from Goodband et al., 1993.
Grinding
Grinding is an essential first step in manufacturing
diets for swine. Whole grains are poorly utilized by
the pig and un-ground grains do not create a very
uniform medium for delivering minerals, vitamins
and protein in the mixed feed. It may surprise some
that older pigs benefit more from ground feed than
younger pigs because as pigs age, they grind their
food less before swallowing (Figure 10-1).
Table 10-2. Effect of Fineness of Grind on the
Performance ofFinishing Pigs Fed Barley-based Diets.
Screen size, mm 3.2 4.6 6.8
Particle size, µm 714 902 1146
Daily gain, g 890 820 810
Daily feed, g 2940 2820 2950
Feed:gain 3.32 3.58 3.65
Source: Adapted from Goodband et al., 1993.
Figure 10-1. Improvement due to Grinding on the
Digestibility of Nutrients for Two Sizes of Pigs
In general, it is suggested that barley should be
ground using a 3.2 mm (1/8") screen. On the other
hand, com should be ground using a 4.6 mm (3/
16") screen; there is ample evidence to show that a
4.6 mm screen reduces growth rate (5 - 8%) and
feed conversion (5%) compared to the smaller size
screen (4.6 mm). The data in Tables 10-1 and 10-2
illustrate the results of trials at Kansas State Univer-
sity using barley-based diets.
Dietary particle size also affects sow performance
(Table 10-3). While the smaller particle size im-
proved productivity, the incidence ofulcers was
also increased.
Photo 10-2.
ProteinEnergy
• 34kg
• 70kg
Dry Matter
� 30
-"'a> 20
Cl
s
"O
� 10
0
....Q.
E
- 0
Hammers and screens must be replaced regularly to
ensure constant diet quality.
216

235. Table 10-3. Effect of Particle Size on the Perform-
ance of Lactating Sows Fed a Corn-based Diet.
Particle size, um
400 600 900 1200
Litter size, d2l 8.9 9.4 9.0 9.0
Sow wt. loss, kg 8.0 6.8 8.5 3.7
Sow backfat
loss, mm 3.3 3.8 4.6 4.1
Litter weight, kg 50.4 50.4 48.9 46.9
Feed intake, kg 4.4 4.3 4.2 4.2
Diet digestibility, % 88.6 86.7 85.4 84.4
Source: Adapted from Goodband et al., 1993.
In addition to the potential for increased ulcers,
there are other down sides to seeking a more finely
ground diet: mill output is reduced, the power
demands per tonne ofdiet increase (Table I0-4),
palatability may suffer and dustiness will increase.
Another consideration is shrink, a factor often
ignored when calculating the true cost ofmanufac-
turing feeds. It refers to material lost as dust and
moisture and is believed to increase in parallel with
fineness. Although shrink is difficult to quantify,
most estimates range from one to three percent.
Table 10-4. Impact of Fineness of Grind on Mill
Productivity and Energy Efficiency.
Particle size Energy cost Production Rates
(urn) (Kwh/tonne) (tonnes/hr)
400 7.5 2.1
600 4.1 4.0
800 3.3 4.3
1000 2.7 4.3
Source: Adapted from Wondra et al.. 1992, J. Anim. Sci.
70(Suppl. 1 ):239.
Many factors influence the efficiency ofthe
grinding process. Screen size ofthe mill is impor-
tant as well as the condition ofthe screen and the
hammers. Nonna! wear and tear during grinding
will result in uneven screen size, broken screens and
worn hammers and will result in a poorjob of
grinding if they are not replaced. Based on a report
by Pouteaux, 1988, screen wear is much more
serious than hammer wear (Table 10-5).
Other factors may also play a role in the quality of
grinding. These include the speed of the mill, the
design ofthe hammers and screens, the ingredient
transporting system and the physical characteristics
ofthe grains, most important of which is moisture.
Broad recommendations suggesting a specific
screen size must be interpreted with care since a
universal guide is not possible. This is graphically
shown in Table l 0-5. The same screen size and
hammer speed were employed for both the hammer
and screen studies. Only the brand of hammer mill
differed. Nevertheless, mean particle diameter,
particle surface area and particles per gram varied
significantly, even with new equipment. The best
alternative is to determine mean particle size on
each diet and adjust mills accordingly. Mean
particle size for market hogs and sows should be
650 to 750µ.m.
Photo 10-3.
Proportioner-type mills are very common in the swine
industry. However, for best results, they must be
carefully calibrated and regularly re-calibrated.
217

236. Table 10-5. Effect of Screen and Hammer Wear on Grinding Effectiveness
Mean Particle Surface Area Particles/Gram
Diameter (microns) (cm2 per gram)
Peas
New Screen 646 179 130,480
Worn Screen 344 355 1, 132,500
(Difference) ( I .88x) (l.98x) (8.68x)
New Hammers 399 393 2,244,800
Worn Hammers 417 397 1,659,000
(Difference) (l.05x) (1.0lx) ( l.35x)
Barley
New Screen 692 229 118,200
Worn Screen 388 419 311,400
(Difference) (l .78x) ( l .83x) (2.46x)
New Hammers 633 274 180,700
Worn Hammers 627 250 124,100
(Difference) (l.Olx) (1.1 Ox) (l .46x)
Wheat (HRS)
New Screen 772 186 73,290
Worn Screen 358 427 938,200
(Difference) (2.16x) (2.30x) (12.8x)
Wheat (Winter)
New Hammers 443 390 2.319,500
Worn Hammers 433 392 1,841,900
(Difference) (l.02x) (--) (l.26x)
x: The number oftimes the smaller value exceeds the larger value in a column.
All studies were conducted with a 7/64" (2.78mm) screen. Both the screen and hammer study employed a 100 HP
tear-drop circular hammer mill operated at 3600 RPM. The mill used for the screen study though, was a different
brand than that used for the hammer study.
Adapted from Pouteaux, 1988. Proc. Alberta Pork Congress. Red Deer, pp.20.
The most commonly recommended screen sizes
for swine diets based on barley range from 3.0 to
3.5 mm. Often. producers should use these as
guidelines only, considering them with the other
variables involved in manufacturing swine diets
such as moisture content, nature ofthe grain and the
feed mill itself. Producers do not have access to
analyses ofparticle size, therefore visual inspection
of the ground feed remains important. In terms of
final particle size, screen size is Jess important for
barley than for wheat, as shown in Table I 0-5.
As introduced previously. the incidence ofgastric
ulcers tends to increase with the use offinely
ground feeds (Table I 0-6 and I 0-7).
218

237. Table 10-6. Effect of Fineness of Grind of Corn on Incidence of Ulcers and Other Stomach Lesions in Swine
Hammermill Screen Size (mm}
1.6 6.4 12.7
Fineness of Grind
Mean Particle Size (microns) 465 820 1,363
Surface Area (cm2/gm) 110 72 52
Stomach Lesions(%)
Normal Stomachs 0 50 63
Comifications 25 38 38
Erosions 25 13 0
Slight Ulcers 38 0 0
Serious Ulcers 13 0 0
Adapted from Wu and Allee. 1984. Kansas State University Swine Day Progress Report pp. 83-88.
Table 10-7. Effect of Fineness of Grind of Barley on
the Incidence ofUlcers and Other Stomach Lesions
in Swine.
Hammermill Screen Size, (mm)
3.2 6.4
Fineness of Grind
Mean Particle Size
(microns) 71 l 1159
Surface Area (cm2/gm) 79 50
Stomach Lesions(%)
Normal Stomachs 17 67
Comifications 33 17
Erosions 0 17
Slight Ulcers 0 0
Serious Ulcers 0 0
Adapted from Goodband 1986. Master's Thesis. Kansas
State University, Manhattan, KS.
Mixing
Mixing is often taken for granted as a simple
process that requires little attention to quality
control. Unfortunately, nothing could be further
from the truth! Mixer adjustment, mixing time and
mixer design are all important variables in develop-
ing a proper protocol. Mixing efficiency is gener-
ally evaluated by taking lO to 12 samples from
within a single batch and analysing each sample
individually for a single nutrient such as sodium,
chloride, iron or lysine; sodium and chloride are the
lowest cost assays. Tracer particles can be used as
an alternative.
It should also be noted that as farms move to
phase feeding, where nutrient supply is closely
linked to nutrient requirements, the importance of
diet uniformity will be much greater; this is due to
the fact that single phase diets, for example, tend to
provide nutrients in excess ofrequirement and thus
provide some degree ofprotection from poor diet
mixing.
In all cases, the variation ofthe nutrient within the
batch is expressed as the coefficient ofvariation
(C.V.). In general, the objective of most mixing
systems is to reduce nutrient variability within a mix
to a C.V. of less than 10% and certainly no greater
than 15%. Excessive variability within a mix
reduces growth rate and feed efficiency (Tables I0-
8 and 10-9).
Table 10-8. Impact of Mixing Time on Diet Uniform-
ity and Performance of Weanling Pigs.
Mixing time, min.
0 0.5 2.0 4.0
Coefficient
ofvariation 100+ 28 16 12
Daily gain, g1
268 377 381 399
Daily feed, g1
599 712 703 721
Feed efficiency1
2.24 1.89 1.85 l.81
1
Effect ofmixing time significant, P < 0.05
Source: Adapted from Traylor ct al., 1994.
219

238. While proper mix time is required to achieve
adequate mixing, worn or poorly adjusted parts may
also contribute to a poor mix. Operators must be
careful not to exceed the recommended capacity of
the mixer; otherwise poor mixing efficiency is
almost a certainty.
There are two general types of mixers: horizontal
and vertical. The following comments are generali-
ties only; differences will exist among manufactur-
ers due to variation in design. Typically, horizontal
mixers are more expensive to purchase than vertical
mixers but have a lower maintenance cost, in part
'
because they have a slower ribbon speed ofrotation
(30 to 40 rpm vs. 200 to 300 rpm). Also, horizon-
tal mixers can generally handle higher quantities of
added liquids than vertical mixers.
Horizontal mixers may employ either paddles or
ribbons, or a combination ofthe two, circulating
within the batch to achieve a uniform mix. Typical
mixing times for horizontal mixers range from 3 to
6 minutes, while for vertical mixers, a somewhat
longer period- 8 to 15 minutes - may be required to
bring the coefficient ofvariation below the desired
I0%. Portable grinder mixers are a version ofthe
vertical mixer described above. Studies in which
mixing efficiency has been properly evaluated
suggest that for a mixer in good repair, mixing for
I 2-17 minutes after the addition ofthe last ingredi-
ent should suffice.
The proper order of addition of ingredients is also
important. For best results, one-halfto two-thirds
ofthe major ingredient (eg. barley) should be added
first. Intermediate ingredients, such as supplement,
soybean meal or canola meal can then be added,
followed by the minor ingredients such as premix or
salt. Finally, the remainder of the major ingredient
can be added.
Table 10-9. Impact of Mixing Time on Diet Uniform-
ity and Performance ofFinishing Swine.
Mixing time, min
0 0.5 2.0 4.0
Coefficient
ofvariation 53.8 14.8 12.5 9.6
Daily gain, g 776 808 794 785
Daily feed, g 2945 2904 2886 2881
Feed conversion 3.80 3.60 3.63 3.67
Source: Adapted from Traylor et al., 1994.
Pelleting
Swine diets are pelleted for handling reasons and
to improve performance. The increased feed
efficiency is believed to be due to reduced wastage
and perhaps improved digestibility. A survey of
117 experiments showed an average increase in
growth rate of6.6% and an improvement in feed
efficiency of7.9% due to pelleting. The benefit
depends on the nature ofthe ingredients used.
Generally, improvement in performance is greater
with more fibrous feeds. Therefore greater benefits
from pelleting would be expected from barley than
from wheat or com. One study found that the
advantage to pelleting corn in terms offeed effi-
ciency was approximately 11% while improvement
in growth rate ranged from 4-9%, depending on the
age ofthe pig; this was confirmed by a recent report
from Kansas State University (Table 10-10).
A survey of lO experiments using barley-based
diets suggested that on average, pelleting improved
growth rate and feed efficiency by 15%. On bal-
ance this appears to be high, but improvement in the
range of7-9% would not be unexpected. For
example, Bell and Keith reported an average 4.7%
improvement in growing pigs and an average 12.6%
improvement in finishing pigs fed barley- or barley
and wheat-based diets (Table I 0-11 ).
220

239. Table 10-10. Impact of Pelleting Com-based Diets on Finishing Pig Performance, Nutrient Digestibility and
the Incidence of Ulcers.
Pig performance
Initial wt., kg
Final wt., kg
Ave. daily gain, kg
Ave. daily feed, kg
Feed conversion
Apparent nutrient digestibility, %
Dry matter
Nitrogen
Gross energy
Stomach keratinization1
Stomach lesions1
Meal Pellet Difference, %
68
119
0.83 0.90 +8.8
3.02 3.11 +3.2
3.65 3.46 +5.2
86.2 86.9 +0.8
83.1 83.4 +0.4
87.0 87.3 +0.3
1.60 1.63 0.0
0.32 0.97 +203
'Lesions and degree ofkeratinization in easophageal region of the stomach scored on a scale ofO to 3, with 3 being
the most severe.
Source: Adapted from Wondra et al.. 1992a.
Photo 10-4.
Pelleting helps to increase nutrient digestibility and
reduce ingredient separation in swine diets.
Photo courtesy of Federated Co-operatives Ltd.
There are a number ofthings that can be done if
ulcers are a problem. In the short-term, hay or a
similar material can be offered to the animals ad lib.
This practice is most effective but may not be
practical in barns using liquid manure pits. A
second option is to include approximately 10%
whole grain (eg. oats or barley) in the diet. Pellet
quality may suffer somewhat, especially in diets
based on corn, but it is an effective method for
treating ulcers.
The preferred pellet size depends on the age of
the animal being fed. The young pig prefers a
smaller-sized feed, and therefore small or short-cut
pellets or crumbles are best. Crumbled creep feeds
tend to stimulate intake. As the pig gets older,
larger pellets are quite acceptable.
221

240. Table 10-1 J. Effect of Pelleting Diets Based on Canela (seed and/or meal) and Cereal Grains (barley or barley
plus wheat) on Pig Performance
Mash Pellets Difference %
Growing pigs (23-59 kg)
Ave. daily gain, kg 0.67 0.72 +7.5%
Ave. daily feed, kg 1.89 1.83 -3.2%
Feed conversion 2.83 2.55 +9.9%
Finishing pigs (59-lOOkg)
Ave. daily gain, kg 0.73 0.87 +19.2%
Ave. daily feed. kg 2.73 2.98 +9.2%
Feed conversion 3.78 3.43 +9.3%
Source: Adapted from Bell and Keith, 1991. Annual Report, Prairie Swine Centre, Saskatoon, SK. pp. 21-24.
Pellet quality is a subject that attracts a great deal
ofattention in feed manufacturing and probably
receives more attention than is necessary ifa pro-
ducer's major concern is pig performance. Pellet
durability is heavily influenced by diet composition.
Wheat in particular is a good binding agent, while
pellets made of com do not hold together as well.
When pigs have access to pellets and fines, they
appear to prefer the pellets and let the fines collect
in the corner of the feeder. This prompts concern
on the part ofthe producer. Recent studies at
Kansas State University reveal that the presence of
fines has little effect on growth rate, but reduces
feed efficiency (Tables 10-12 and 10-13).
Although many factors are believed to be in-
volved. gastric ulcers tend to increase when pigs are
fed pelleted diets. Part ofthe problem may be
related to the fineness of grind used to prepare
grains for pelleting. A finer grind results in better
quality pellets; consequently, pellet-mill operators
tend to use finely ground grains in an attempt to
minimize customer complaints. With a coarser
grind. pellet quality will suffer but the incidence of
ulcers will be reduced. The heating process associ-
ated with pelleting results in gelatinization ofthe
grain starches and has also been implicated as a
cause ofulcers. In the example presented in Table
10-10, the grains used in both the meal and the
pelleted diets were ground to the same particle size.
Table 10-12. Effect of Pellet Fines on Performance ofFinishing Pigs Fed a Corned-based Diet (Initial wt.= 54kg).
Ave. gain, kg/d
Ave. feed intake, kg/d
Feed conversion1
Meal
0.93
2.58
2.78
Screened Percentage fines
pellets 20 40 60
0.96 0.96 0.96 0.94
2.54 2.66 2.66 2.65
2.65 2.78 2.77 2.82
I
Linear effect of fines significant, P<O. IO
Source: Stark et al., 1993.
222

241. Table 10-13. Effect of Pelleting and Fines on Performance of Newly-weaned Pigs Fed Corn-based Diets (Initial
wt.= 5.7 kg).
d7tod21
Ave. gain, kg/d
Ave. feed intake, kg/d
Feed conversion'>
d7 to d35
Ave. gain, kg/d
Ave. feed intake, kg/d
Feed conversion1
•
3
I
Effect ofpelleting significant, P<0.01
2
Effect offines significant, P<0.05
3
Effect of fines significant, P<0.07
Source: Stark et al., 1993.
Meal
0.32
0.56
1.73
0.47
0.78
1.67
Pellets
0.36
0.52
1.44
0.49
0.73
1.50
Pellets + 25% fines
0.34
0.54
1.55
0.49
0.76
l.54
Liquid Feeding
Liquid feeding was popular many years ago but
fell into disfavour for a variety ofreasons. Most of
the reasons were related to problems with the
mechanical equipment. New approaches have
rekindled interest.
For example, one "version" of liquid feeding is
the use of"wet-dry" feeders, a compromise
between liquid and dry feeding. Feed is delivered
to the self-feeder in dry form, but a nipple waterer
located below the feeding platform allows the pig to
drink water at the same time as it is eating. The pig
can even mix the dry feed with water in the dish
located below both the feeding platform and the
waterer.
Field studies in Manitoba indicate that the wet-dry
feeders are well received by the pigs, and the feed
intake may be improved over conventional dry
feeders. To maintain the cleanliness ofthe pens, the
feeders should be placed within 2 feet ofthe slatted
area, since some water spillage does occur. Wet-dry
feeders have proven to be an efTective way of
incorporating liquid whey into the feeding program.
Whey is delivered via the nipples and the
composition ofthe dry feed is adjusted to
complement the whey composition.
True liquid feeding systems are also appearing on
the Canadian market. The new systems offer more
precision in mixing and delivery and if they are
linked to computer systems, they provide a much
greater degree ofcontrol than was previously
possible. It is too early to offer a definite evalua-
tion ofthese newer units, but they do offer consid-
erable advantages over previous liquid feeding
systems. Small improvements in pig performance
can be expected with such feeding systems. The
main drawback is cost and the difficulty ofadding
antibiotics to certain diets without contaminating
others.
Photo 10-5.
Computer controUed liquid feeding systems which supply
exact amounts of feed to each pen at specified times are
relatively new on the market, but gaining in popularity.
223

242. On a dry matter basis, there is very little
difference in the feeding value of com or barley of
equal quality stored in an oxygen limiting unit
compared to being conventionally dried. High
moisture storage appears to increase the availability
ofphosphorous in the grain but it may also reduce
the amounts of vitamins A and E. The main point
to keep in mind is that rations must be adjusted to
compensate for the extra moisture content of the
grain.
The grain should be ground and well packed in
the silo to eliminate oxygen. All doors should be
sealed; unsealed systems result in losses of2-5%
compared to oxygen limiting systems. Once a
vertical silo is opened, a minimum ofthree inches
must be removed per day to prevent spoilage. This
may have to be increased during warm weather.
Grain dryers are used to reduce the moisture content
of wet grains thus preventing spoilage.
Sealed, oxygen-limiting silos are the most
convenient systems for storing high-moisture grains,
but they are also the most expensive. Vertical
concrete silos or horizontal silos can be used
successfully, although the level ofmanagement
required is greater than with the oxygen-limiting
systems. Mechanization offeeding is also more
difficult. especially in the case ofthe horizontal
silos.High Moisture Grains
High moisture storage and feeding ofgrain is
popular in areas where grains are harvested wet and
must then be dried before conventional storage.
High moisture storage involves the use ofeither
oxygen limiting structures or the addition of
acidifying compounds. Both systems inhibit
undesirable microbial deterioration, allowing the
wet grain to be stored until fed. The systems add to
the cost of storage but save on the cost of drying.
The use ofhigh moisture grain can improve
harvesting management, since a dryer tends to slow
down the grain handling process. High moisture
grains stored in silos should normally fall within the
range of22-28% moisture. This range limits the
period of time for harvesting but provides ideal
moisture to generate the desired level of
fermentation.
Drying Grains
Depending on cropping practices and weather
conditions, grains may be dried to reduce moisture
content and thus prevent spoilage during storage.
An alternative to drying is to store the product as a
high moisture grain. This method is discussed later
in the chapter. Research has shown that corn can be
dried to 12-15% moisture using temperatures of
up to 110°C with no adverse affects on pig
performance. Temperatures in excess of 150°C
have been shown to affect the palatability ofcorn
to the pig.
Liquid or paste feeding has shown some benefits Photo 10-6.
for the young weanling pig. Liquid feeding refers
to a feed with a high water content (2: I water:feed
ratio), while paste feeding is drier but still moist
(J .3-1.5: 1 water:feed ratio). Young pigs tend to eat
wet feed more readily. The problem is maintaining
feed freshness. Starter diets are high in milk prod-
ucts and tend to develop off-flavours very quickly.
However, if suitable antioxidants arc included in the
diet and the feed delivery system is managed
properly, these concerns can be largely overcome.
The key to liquid or paste feeding systems is to
provide fresh feed on a regular basis.
224

243. Organic acids have been used extensively as
preservatives for high moisture grains. The
different types include propionic, acetic, isobutyric,
formic and benzoic acids or their various
combinations. These acids preserve the grain by
preventing mold growth and by killing the grain
germ. Organic acids can be corrosive to any metal
they come in contact with such as transportation and
storage equipment. Ifmetal granaries are to be
used, they must be lined with a protective covering
to avoid premature rusting.
Acid preservation systems are more flexible than
the use ofoxygen limiting silos. The advantage is
that continuous feeding is not necessary. The acid
remains with the grain until feeding: therefore
spoilage outside the granary is eliminated.
Pigs normally perform very well on high-moisture
grain. Dustiness is reduced so the wet grain tends to
be very palatable. It should not be used for the very
young pig though, due to the high moisture content
ofthe grain and the limited gut capacity ofthe small
pig. Once high moisture grain is harvested and
stored, there tends to be very little resale market
available. The owner is generally committed to
feeding it to livestock.
Mixing Feeds on the Farm
In Canada, a high but declining proportion of
feeds are manufactured on the farm. There are
many indications though, that many home-
maufactured diets are not well mixed. Toe results
ofsurveys in several provinces indicate that up to
75% of feeds submitted to feed testing laboratories
for analysis fail to meet the nutrient requirements of
the pigs being fed. The problem can occur at any
number of the steps involved in feed manufacturing:
diet formulation, feed mixing or feed delivery. A
proper quality control program must be in place to
ensure diet quality and consistency. A system for
quality control was discussed in detail in Chapter 5.
Ingredients grown on the farm should be analysed at
least for crude protein and moisture.
[fa proportioner-type mill is being used, the
bushel weight should also be measured. Bushel
weight should be checked on a regular basis
because changes in bushel weight will alter mixing
accuracy. Appendix II outlines the steps required to
calibrate a typical proportioner-type mill, one of the
common mixing systems.
It has been suggested that the moisture content of
the ingredients will influence the rate ofaddition in
proportioner-type mills. This is because moisture
content affects bushel weight. However, moisture
tests from a feed testing laboratory may not be
completely accurate. This is because the moisture
content ofa sample ofgrain can change a great deal
from the time it is sampled at the farm until it is
finally measured in the lab. This problem is
relatively minor for dry grains, but increases as
actual moisture content increases. Researchers go
to great pains to measure moisture accurately under
laboratory conditions that would not be practical for
farmers. Consequently, a good bushel weight is
likely to be the best overall measurement on a grain
sample, to determine ifmill re-calibration is
required.
For cereal grains, calcium and phosphorus
analysis may not be required, as they are quite
consistent from year to year and because they
contribute relatively small proportions ofthe total
Photo 10-7.
To obtain best results, P.T.O. mixers should be operated
for 12 to 17 minutes after adding the last ingredient.
225

244. quantities in the diet. Purchased ingredients should
be analysed for protein, calcium, phosphorus and
salt on a regular basis, perhaps every 2-3 months, to
ensure that the assumed nutrient content is indeed
correct.
Mixed diets should be sampled monthly and
analysed as required. This step ensures that mixing
and formulation steps have been completed
correctly, and provides a final check on the quality
of the feeds being offered to the pigs. Refer to
Chapter 5 for a recommended feed sampling and
analysis schedule.
Processing Problems
Achieving a proper mix on the farm is not easy,
based on the results ofsurveys showing generally
poor quality control. Surveys continually reveal
that diets lack nutrient balance and often uniformity.
One major problem is separation. For example,
Table l0-14 summarizes the results ofa study
conducted on a commercial farm in Saskatchewan
using a typical proportioner-type mill. Feed was
mixed in batches and stored in a hopper-bottomed
(centre flow) steel bin. Feed samples were
collected for analysis at the beginning, middle and
end ofthe batch as it left the storage bin.
Considerable separation was taking place, such that
pigs were receiving diets ofvaried composition,
depending on the location of the feed within the
storage tank. Since this diet was formulated to be a
pre-grower, the very high crude fibre and low
protein level found in the latter part of the batch
was a serious cause for concern.
To improve uniformity, dispersion tubes should
be placed inside feed bins to prevent segregation of
ground feeds. Coarse grinding may also help, but
losses in performance must be avoided. Pelleting of
course would solve the problem, but is generally not
available on most farms.
Dustiness is another problem. Recognition that
dust in the barn poses a threat to the health of
humans as well as pigs has focused greater attention
on this subject. Adding 0.5-2% fat to the diet has
Table 10-14. Separation of Feeds Following Mixing on
the Farm.
Portion of Storage Tank
Nutrient Start Middle End
(%)
Protein 17.60 17.40 15.70
Calciwn 1.09 0.99 0.74
Phosphorus 0.95 0.85 0.65
Fibre 3.80 4.20 9.00
Salt 0.74 0.71 0.61
(parts per million)
Iron 310 200 200
Zinc 260 140 140
Manganese 50 40 40
Copper 23 20 20
A pre-grower diet was mixed using a proportioner-type
mill and stored in a hopper-bottomed bin before feeding.
Feed samples were collected at three stages of emptying:
beginning, middle and end ofthe batch.
proven beneficial in removing nuisance dust, but is
very poor at controlling respirable dust - that which
is small enough to enter the lungs and thus poten-
tially contribute to respiratory problems. Including
whole seed canola or soybeans in the formula is one
way ofaccomplishing this objective and has the
added benefit ofincreasing the energy content of
the diet. Sprinkling oil directly in the barn is much
more effective in reducing dust - by up to 80% -
and at less cost than adding the oil to the diet.
Care must be taken to increase amino acid
(protein) content of the diet when any fat source is
used; otherwise, poor carcass grades may result.
For every l% vegetable fat added to the diet, the
limiting amino acids should be increased by about
4%. For example, for every l% of fat added to a
finisher diet, lysine should rise by about 0.03
percentage units (eg. lysine increased from 0.75%
to 0.78%). This can be accomplished most easily
by increasing the amount ofprotein by 4% (i.e.
crude protein increased from 16.5% to 17.2%).
When whole seed canola or soybeans are used, they
add protein as well as fat, so the increase in protein
per l% fat would be 1.5-2.0%.
226

245. Feeds Act and Regulation
Everyone manufacturing feeds, whether they are a
commercial feed company or a private farmer
mixing feed for his own use, should be familiar
with three publications: the Feeds Act ( 1976). the
Feeds Regulations ( 1983, revised) and the Com-
pendium ofMedicating Ingredient Brochures
(CMIB). These are federal statutes and guides
governing the manufacture and use of livestock
feeds in Canada. Copies ofall three can be ob-
tained from the Federal Government. They detail
the legal responsibilities associated with the produc-
tion offeeds intended for use in livestock opera-
tions; contrary to common thinking, these rules
apply equally to both commercial feed companies
and farmers manufacturing their own feeds. How-
ever, the Feeds Act states that it does not apply to a
feed:
"that is manufactured by a livestock producer if it
is not offered for sale and has not had incorpo-
rated into it any drug or other substance that may
adversely affect human health or the environment
or that is sold by the individual grower thereof if
it is free from prescribed deleterious substance�."
Simply stated, ifthe individual pork producer is
mixing his own diets for his own use and is not
adding anything to the feed that will be harmful to
human health or the environment, then he or she is
not bound by the legislation contained in the Act.
However. if feed medications are used such as
antibiotic-type growth promotants, then the Feeds
Act must be adhered to.
The following discussion summarizes general
points of interest to livestock producers. It is not
intended to be comprehensive; anyone interested in
answers to specific questions should consult the Act
or contact their nearest Agriculture Canada office.
Essentially, the objectives ofthe Feeds Act are to
ensure that:
I. All animal feeds are efficacious in terms of
the original purposes for which they were
intended. For example. a sow lactation diet
should support milk production in the sow.
2. When livestock diets are fed to animals
resulting human food products, such as meat or
milk, do not pose any kind of health threat to
persons consuming them. For example, the Act
specifically forbids the use of in-feed drugs in
such kind or quantity that would result in residue
in the meat intended for human consumption.
3. Animal feeds do not pose a health threat to
the animals consuming them.
4. Animal feeds do not pose a threat to the
environment.
The Food Production and Inspection Branch
administers the Feeds Act and Feeds Regulations.
As a consequence ofchanges in the nature ofthe
livestock feed industry, and in their view, to obtain
the best results from a limited budget, they are
focusing less attention on random visits to commer-
cial feed mills, a major activity in the past, and
spending more time following up on suspected
abuses of in-feed drug usage at commercial mills or
on livestock farms.
At the present time, all feeds imported,
manufactured or sold in Canada must be registered
with the Federal Government, unless they are
s�eci�ically exempted by the Feeds Act; fortunately,
since rt takes considerable time and effort (and
S95.00) to register a single feed, the majority of
feeds are exempted. For example, a feed is
exempted from registration if it does not contain
any medicating ingredients and meets specified
minimum requirements with respect to nutrient
composition. These nutrient specifications are
outlined in Table 4, Schedule I ofthe Feeds
Regulations. Table 10-7 summarizes the
information as it relates to swine. It must be
recognized that Table 4 of the Regulations is
continually being reviewed and adjusted; therefore,
the reader is cautioned that changes to the
Regulations may have occurred since this book was
written and that Table 10-7 may not be completely
up to date.
As indicated, registration requirements do not
apply ifthe feeds are manufactured for a livestock
producer's own use and do not contain medications;
similarly, ifthe feed contains medications added at
levels defined in the CMIB, the registration
227

246. requirements are again waived. The CMIB defines
which drugs are permitted to be used in swine diets,
what levels may legally be added to the diet and
identifies restrictions on their use, such as
withdrawal times. Levels ofdrugs or combinations
ofdrugs, not included in the CMIB cannot be used
in swine diets unless the producer or feed
manufacturer receives a veterinary prescription.
Agriculture Canada is primarily concerned with
diets that contain medications or other substances
that pose a potential hazard to animal or human
health and if not used properly could result in
carcass residue. They are also concerned about the
use ofother substances that may be harmful to the
environment such as high levels ofcopper, which
accumulate in manure and become concentrated on
land where it is spread.
It is clear that the government wishes to be very
careful about permitting the use ofmedications in
livestock feeds. Anyone mixing diets which include
medications may be required to submit to an on-
farm inspection. The Act discusses such inspec-
tions offeed mixing facilities. They are intended to
ensure that, if medications are going to be used,
they are mixed adequately and safely. In this
respect, the on-farm feed mixing facility is treated
exactly the same as a large commercial feed mill.
Such an inspection could include a listing ofall
medicating ingredients used and determine ifsuch a
premix is approved for use, a check of feed han-
dling, delivery and mixing facilities to ensure they
are in good repair and adequate for the job, and an
evaluation ofmanufacturing practices such as those
related to preventing inadvertent contamination of
other, un-medicated feeds mixed at the same site.
Table 10-15. Nutrient Guarantees Required for Swine Diets that are Exempt from Registration Requirements.
Nutrient Minimum Maximum Nutrient Minimum Maximum
Calcium,% 0.80(1) 2.00 Magnesium, % 0.04 0.30
0.75(2,3) Manganese, mg/kg 10 200
0.5(4)
Cobalt, mg/kg NRS 5 Phosphorus, % 0.60(1) 2.00
0.50(4)
Copper, mg/kg 6 125 Potassium, % 0.2 2.0
Iodine, mg/kg 0.2 10 Sodium,% 0.20(2) 0.80
Iron, mg/kg 150(5) 750 0.15(3)
80(3) 0.10(4)
40(4)
Selenium, mg/kg NRS 0.30
Vitamin A, IU/kg 4,000(3) 20,000 added
1,300(6)
2,000(4) Sulphur,% NRS NRS
Vitamin D, TU/kg 125(4) 1,500
200(7)
Zinc,mg/kg 100 500 Vitamin E, TU/kg 10 NRS
Minimum and maximum nutrient composition specified in the Feed Regulations for unregistered diets fed to various
classes ofswine:( I) 1- l O kg bodyweight; (2)1actation; (3)breeding; (4)all classes not specified; (5)up to 20 kg
bodyweight; (6)20 kg to market; (7)up to 60 kg; (NRS)No requirement specified. Diets offered for sale which fall
within these ranges need not be registered. The limitations specified in this table do not apply to individual livestock
producers who are exempt from these regulations (see above).
228

247. Clearly, the use of medications in livestock diets
is considered a serious matter which must be
carefully controlled to ensure that the pork industry
produces a safe, wholesome product. It is the
responsibility ofeach individual producer to ensure
that proper procedures are followed.
Because they are in the business ofselling feeds,
the commercial feed manufacturer is expected to
meet certain standards beyond those applying to the
individual farmer. All feeds must be carefully
labelled. Although the Regulations carefully define
labelling requirements, the major objective is to
provide the buyer with sufficient information to use
the feed effectively and safely. Labels include
feeding instructions, withdrawal times if
medications are involved and cautions with respect
to proper use. All diets manufactured for sale by
feed companies that contain nutrients outside the
bounds defined in Table 4 ofthe Feeds Regulations
must be registered with the Federal Government.
An exception is what the Regulations refer to as a
customer formula feed. Ifthe pork producer
specifically asks for a feed that may contain levels
above or below the standards outlined in Table 4
and provides a signed request form listing all the
ingredients to be used, the feed manufacturer does
not have to register the feed with the Federal
government. Consequently, requests from farmers
to commercial feed manufacturers should keep such
restrictions in mind.
Agriculture Canada provides the 'Medicated Feed
Information Guide'. Like any legal document, the
Feeds Act is written in very precise legal language
which is sometimes difficult to understand. This
Guide is useful because it explains the Feeds Act
and associated documents in simpler terms.
Everyone mixing feeds on the farm would be well
advised to read it, so they are familiar with their
legal obligations. The Guide also provides useful
tips on feed mixing and handling to help avoid
potential problems.
Additional Reading and References
Goodband, R.D., 1986. The effects of barley on
starter and finishing pig performance. Master's
Thesis, Kansas State University, Manhattan, KS.
Goodband, R.D., M.D. Tokach and J.L. Nelssen.
1993. Diet particle size influences pig
performance. Proc. Manitoba Swine Seminar,
Winnipeg, MB. pp. 91 - 104.
Stark, C.R., K.C. Behnke, J.D. Hancock, and R.H.
Hines. 1993. Pellet quality affects growth
performance ofnursery and finishing pigs. Swine
Day Progress Report pp. 67-70.
Traylor, S.L., J.D. Hancock, K.C. Behnke, C.R.
Stark, and R.H. Hines. 1994. Mix time affects diet
uniformity and growth performance of nursery and
finishing pigs. Swine Day Progress Report pp. 171-
175.
Wondra, K.J., J.D. Hancock, K.C. Behnke, C.H.
Fahrenholz, C.R. Stark, and R.H. Hines. 1992a.
Effects ofmill type (hammer vs roller) and particle
size uniformity on growth performance, nutrient
digestibility, and stomach morphology in finishing
pigs. Swine Day Progress Report pp.126-129.
Wondra, K.J., J.D. Hancock, K.C. Behnke, G.A.
Kennedy, and R.H. Hines. l992b. Does diet form
(pelleted vs meal) affect optimum particle size of
com for finishing pigs? Swine Day Progress Report
pp. 122-125.
Wondra, K.J., J.D. Hancock, K.C. Behnke, R.H.
Hines, and C.R. Stark. 1993. Effects of
hammerrnills and roller mills on growth
performance, nutrient digestibility, and stomach
morphology in finishing pigs. Swine Day Progress
Report pp.135-138.
229

248. 230

249. 11. TOXIC SUBSTANCES IN FEEDS
Potential Toxins or Toxin Producers
Which May be
Present in Common Feed Ingredients
In mature cereal grains, 60% to 80% of the total
phosphorus is so bound; in soybean meal, about
halfofthe phosphorus exists as phytate phosphorus.
to formulate rations around them. Research is
underway to negate the effects of many ofthese
toxic factors. The following is a discussion of some
ofthe more common toxicants which may be
encountered when formulating pig diets in Canada.
Phytates
Phytic acid is present in many plant seeds, contain-
ing 6 phosphorus molecules linked to an organic
compound called inositol. In the plant kingdom, it
serves as an important storage form of phosphorus.
Phytic acid may chelate or bind with a variety of
minerals, including calcium, magnesium, iron and
zinc to form phytate. In pig diets, phytate typically
binds calcium and magnesium as well as phospho-
rus; destroying phytate through enzymatic or
processing activity will therefore increase the
utilization of all three mineral elements, notjust
phosphorus as normally assumed.
Exogenous
Fungi
Aspergillus
Fusarium
Penicillium
Ergot
Bacteria
Escherisciacoli
Salmonella
Campylobacter
Listeria
Clostridia
Endogenous
Phytates
Saponins
Estrogens
Trypsin Inhibitors
Tannins
Glucosinolates
Lectins
Thiaminase
Oxalates
Gossypol
Toxins may be substances that occur naturally in
certain species ofplants. Examples are tannins and
phytates; their presence is readily predicted and
appropriate adjustments can be made in the diet
formulation. Toxins can also be the result of
contamination by bacteria or fungi. The bacteria
themselves may be toxic to the pig, or ifthe bacte-
ria or fungi are not poisonous. they may produce
substances which are. This is not a predictable
occurrence and therefore. can be much more diffi-
cult to deal with. Listed adjacent are some ofthe
toxins or toxin producers which may be found in
feeds in Canada. It does not include weed seeds
which may also contain noxious substances.
Mycotoxins are metabolites (products ofmetabo-
lism) offungi, the most common in Canada being
ergot alkaloids, ochratoxin A, zearalenone and the
tricothecenes. These are discussed in detail later in
the chapter.
Toxicants Produced by Plants
Many common feed ingredients contain natural
toxicants and/or toxins which may impair pig
performance. For example, raw soybeans contain
trypsin inhibitors and the enzyme urease. They are
part of the normal plant or seed and are generally
predictable in both quantity and impact on the pig.
Although their presence is undesirable, our knowl-
edge ofanti-nutritional factors allows nutritionists
While the main focus ofanimal nutrition is the
need for - and supply of - nutrients, the feedstuffs
which supply these nutrients may also carry with
them certain toxins or antinutritional factors. Tox-
ins are generally considered to be poisonous sub-
stances present in the feed, often produced by the
host plant or by an organism living in the feed,
which could adversely affect the health and wellbe-
ing of animals; conversely, antinutritional factors
are substances which impair normal feed digestion
or nutrient utilization. A diet can be perfectly
balanced but fail to support optimal growth if it
contains anti-nutritional factors that adversely affect
appetite, feed utilization or animal health.
231

250. Source: BASF Technical Bulletin No. 9201.
Table 11-2. Naturally-occurring Phytase in Common
Feedstuffs.
Table 11-1. Phytate Phosphorus Content of Common
Feedstuffs.
If injected, saponins are highly toxic, attacking
and altering the structure and function ofcell
membranes. However, when administered orally,
their effect is greatly reduced. Saponins impair pig
performance, due to their bitter taste and irritating
High
Medium
Low
Very low
Undetectable
Relative Phytase ActivityFeedstuff
Wheat, rye
Barley
Oats, soybean meal
Com, sorghum
Cottonseed
Total Phytate
Feedstuff Phosphorus, % Phosphorus,
% of total
Alfalfa meal 0.30 0
Barley 0.34 56
Com 0.26 66
Cottonseed meal 1.07 70
Grain sorghum 0.31 68
Oats 0.34 56
Sesame meal l.27 81
Soybean meal 0.61 61
Wheat 0.30 67
Wheat bran 1.37 70
Wheat middlings 0.47 74
Source: Ward, 1994.
Saponins
Saponins are a family ofcompounds found in
many plants ofeconomic importance, including
canola. alfalfa, soybeans, peas, sugarbeets, sunflow-
ers, oats, chickpeas and beans. They are character-
ized by a bitter taste, but are used commercially in
such diverse consumer products as shampoo, soft
drinks, soap and fire extinguishers. The type of
saponin, the concentration present and the physi-
ological effect on swine varies a great deal within
and among plant species.
Table 11-1 provides information on the relative
proportion of total phosphorus present in the form
of phytate in common feedstuffs.
A number offactors will influence the availability
ofphytate phosphorus. Germination releases the
naturally-occurring phytase in cereal grains; within
one week ofgermination, the amount ofphytate
phosphate will be reduced by 50%. Some grains
contain more natural phytase than others; wheat in
particular, is known to be a relatively rich source of
phytase and thus has a higher phosphorus availabil-
ity (Table 11-2).
Phytate is ofnutritional significance because
phosphorus in phytic acid is poorly absorbed by the
pig. In fact, the availability of total phosphorus
from grain sources ranges from 20% in com to 45%
in wheat; barley and oats are intermediate at about
30% availability. These low availabilities are the
result ofpoor utilization ofphytate-bound phospho-
rus - essentially zero bioavailability in com and
oats, 10% in barley and 40% in wheat. In contrast,
inorganic phosphorus supplements, such as
dicalcium phosphate are about 80% available or
better.
Phytase supplements can also be purchased for
inclusion in pig diets; these are normally derived
from a genetically-modified Aspergillus strain.
Biological action will vary with the source, but as a
rule, approximately 500 units ofpbytase per kg of
mixed feed is equivalent to 0.1 % supplemental
phosphorus in the diet. Phytase supplements must
be properly handled to obtain maximum benefit.
Because phytase is an enzyme, it is susceptible to
the effects of heat and moisture. Therefore,
pelleting diets containing phytase must be carefully
controlled to avoid die temperatures in excess of
70°C as losses in enzyme activity may exceed 25%;
alternatively, phytase can be added as a liquid post-
pelleting or used in mash diets.
Certain micronutrients, such as iron sulphate,
copper sulphate or choline chloride will contribute
to phytase breakdown. Therefore, phytase is best
not added to premixes containing trace minerals or
choline; because these ingredients are diluted in
complete feed, their impact on phytase in mixed
diets is greatly reduced.
232

251. effect on the lining ofthe mouth and gut. There is
some suggestion that the absorption ofcertain
nutrients, including vitamins and trace minerals is
altered by saponins, presumably due to changes in
the structure of the lining ofthe gut; for example,
soybean saponins bind zinc and render it less
available, while ginseng saponins actually increase
the absorption of iron. Interestingly, saponins also
lower blood cholesterol levels.
In animal nutrition, concern about impaired
performance due to saponins is most often associ-
ated with alfalfa. The saponin content ofalfalfa
varies according to season, being highest in mid-
summer and tapering offthereafter; not surprisingly,
the saponin content ofsecond cut alfalfa tends to be
higher than that offirst or third cuttings. Plant
breeders are now developing low saponin alfalfa
varieties.
Estrogens (Phytoestrogens)
The estrogen content offeeds can occur from the
plant directly or from contamination with molds
which produce estrogenic mycotoxins. Alfalfa and
soybeans canproduce an estrogenic compound
called coumestrol. The use ofalfalfa pellets in sow
diets has declined, due in part to the fear that
possible estrogenic compounds may impair repro-
ductive performance.
Protease Inhibitors (Trypsin Inhibitors)
Most legume seeds (eg. soybeans, faba beans),
some grains (eg. com, rye, barley and triticale),
alfalfa and potatoes contain protease inhibitors.
These are protein molecules which bind to and
inactivate trypsin or other digestive enzymes that
help to break down protein molecules in the small
intestine. Ofthe protease inhibitors, trypsin inhibi-
tors are best known, but inhibitors ofchymotrypsin
also exist in nature. In practical terms, while
protease inhibitors are widespread throughout the
plant kingdom, the ones ofgreatest significance in
pig nutrition are those found in soybeans, other
beans and triticale.
ln swine nutrition, protease inhibitors are most
often discussed in the context of impaired perform-
ance due to reduced protein digestibility. However,
trypsin inhibitors have been shown to impair per-
formance independent of their impact on protein
digestion, at least in some species. In some species,
but not the pig, the effect oftrypsin inhibitors can
be reduced by supplementation with sulphur amino
acids; this occurs because such animals respond to
trypsin inhibitors by producing more trypsin, a
protein which is particarly rich in sulphur amino
acids. In the pig, inhibition of protein utilization
occurs because the quantity oftrypsin inhibitor
present exceeds the available supply of trypsin, and
increased supply is either not possible or is inad-
equate.
Trypsin inhibitors are readily destroyed by heat;
fifteen minutes at 100°C is sufficient to remove
almost all negative effects. A simple, indirect test,
called the urease test, is often employed to deter-
mine the level oftrypsin inhibitor left after
soybeans have been processed. The enzyme urease
is also present in soybeans; it converts urea to
ammonia and can be tested quite easily. It is as-
sumed that the destruction ofurease during soybean
processing parallels that oftrypsin inhibitor, so that
ifone is inactivated, the other will be similarly
destroyed. Ifthe urease test is negative, this serves
as an indirect indication that trypsin inhibitor has
also been destroyed.
Heating ingredients to destroy protease inhibitors
must be carried out with great care; this is because
excess heat may damage certain amino acids,
especially lysine, rendering them unavailable to the
pig.
Tannins
The term "tannin" was originally used to describe
a group ofplant extracts used in tanning leather.
They are found in many crops, including rapeseed,
soybeans, fababeans, sunflower seeds, alfalfa and
sorghum. More technically speaking, tannins are a
group ofcompounds that bind to proteins, including
dietary proteins, digestive enzymes and proteins
which assist in nutrient absorption in the gut. It is
not surprising, then, that tannins impair the ability
of the pig to use dietary protein, carbohydrates and
fats; however, the most significant impact is directly
on protein utilization. Tannins also reduce palat-
ability, due to a sour taste.
233

252. Tannins are divided into two broad categories:
condensed and hydrolyzable. The latter are named
due to their ability to be readily broken down while
the condensed tannins are much more stable and
complex in structure.
The tannin content ofsorghum differs among
varieties, with yellow sorghum having very low
levels. Tannin content is directly related to bird
resistance in the field; consequently, plant breeders
are faced with the decision to select varieties for
low tannin content, desirable in animal nutrition, or
high resistance to predation by birds, which is
desirable in regions where sorghum is a human food
staple, but is vulnerable to attack by wild birds.
Sorghum tannins are ofthe condensed kind.
The most effective means of addressing the issue
oftannins in swine nutrition is to select crops and
varieties ofcrops with little or no tannin content.
Alternatively, affected crops can be treated with
dilute alkali or polyethylene glycol to improve their
feeding value. Heating is somewhat less effective
because tannins are heat stable.
Glucosinolates
Glucosinolates are common in plants in the
Brassica family, including rapeseed, mustard,
turnips, crambe and kale. They reduce palatability
and impair the function ofthe thyroid gland. Since
the thyroid gland is so important in regulating
animal growth, this can be a serious problem.
Canadian plant breeders have developed low
glucosinolate varieties ofrapeseed; to distinguish
these new varieties with highly different nutrition
characteristics, the term "canola" was coined.
Continued research on lowering the glucosinolate
level to essentially zero is on-going; however, it is
not yet known if these further improvements will
affect animal performance. Meal from current
varieties ofcanola can be fed at high levels to swine
without any apparent effect due to glucosinolatc
activity.
Lectins
Lectins arc either protein or carbohydrate-protein
compounds which share a common characteristic:
the ability to selectively bind certain carbohydrates.
Lectins are known to impair growth, cause diarrhea
and interfere with nutrient utilization.
Found in highest concentration in legumes,
including soybeans, lectins were first associated
with castor beans. The ability ofthe lectins to bind
to cells along the intestinal tract is highly specific,
such that certain Jectins will bind and others will
not. Ifbinding occurs, the lectins may enter the cell
and. if toxic, can initiate a range ofadverse reac-
tions, from greatly enlarged intestinal tissue to
impaired nutrient absorption and depleted body
muscle, fat and glycogen reserves.
Thiaminase
Thiaminase is an enzyme which destroys the B
vitamin thiamine. It is not found in any feedstuff
common in pig diets, but is present in certain fish,
including carp. Ifsuch fish are fed in uncooked
form to swine, problems may occur. Since feeding
raw fish to swine is unlikely, the risk ofproblems
due to thiaminase is remote.
Oxalates
Oxalic acid is a compound with the ability to bind
calcium, rendering it less available for absorption
by the pig. Oxalate poisoning, while common in
grazing species exposed to certain plants, is rare in
swine. However. some feedstuffs that may be
included in swine diets, such as alfalfa. contain
oxalate, lowering the bioavailability ofcalcium.
Gossypol
Gossypol is a yellow pigment found throughout
the cotton plant: in the seed. gossypol is found in
the pigment glands. During processing. the glands
are ruptured and gossypol released. A portion of
the gossypol will bind to protein, primarily the
amino acid lysine, rendering it less available to the
pig. Thus. the higher the portion of bound as
compared to free gossypol, the lower will be the
biological value ofthe protein. The remaining, or
free. gossypol is reactive and affects animals in a
number ofways: depressed appetite. lower weight
gains, impaired lung, heart and liver function,
anemia and male infertility. Free gossypol levels
should not exceed I 00 ppm in pig diets.
234

253. The effects ofgossypol can be reduced by adding
ferrous sulphate to the diet; the generally accepted
recommendation is 1 unit of iron as iron sulphate
per unit of gossypol. Even with added iron, the
maximum upper limit of free gossypol in swine
diets is 400 ppm. Increasing dietary protein is
helpful as well, but rarely economical.
Exogenous Microbes and Toxin
Producers
Bacteria
Contamination of feed by pathogenic microbes
such as certain strains ofSalmonella may lead to
infection of the herd and an outbreak ofdisease. In
the case ofSalmonella, there are more than l ,000
different serotypes, yet only a handful tend to be of
significance in pork production. including S.
choleraesuis and S. typhisuis. Some other Salmo-
nella serotypes have a broad spectrum of hosts and
could therefore infect swine ifthe conditions were
right.
It is unclear how significant a threat feed repre-
sents to herd health. However, owners ofherds
with a minimum disease health status prefer to act
conservatively and avoid any potential health
problems; some therefore refrain from using feed
ingredients which may be more prone to contamina-
tion. This is difficult in practice; although animal
by-product meals are most commonly suspected, all
feeds are at least potentially at risk.
Animal by-products manufactured in modem
facilities are usually processed and handled in ways
that eradicate initial contamination and prevent
reinfection. Dealing with reputable suppliers will
certainly help minimize risk with products such as
meat meal. blood meal, feather meal and plasma
proteins.
However, care in processing animal byproducts
will not eliminate risk. Uncontaminated material.
ofanimal or vegetable source, passed through a
contaminated storage or transport facility will
become infected. Contamination can also occur
through exposure to wild birds, rodents, etc. which
are often carriers of disease. Some producers only
use mixed feeds that have been steam pelleted and
feed trucks that arc regularly sanitized as a further
safeguard against disease transmission. The data in
Table 11-3, based on the results of a survey reported
by the Veterinary Diagnostic Laboratory at the
Pennsylvania State University, illustrates that
removing ingredients ofanimal origin will not
eliminate the risk ofSalmonella contamination.
Table 11-3. The Results of Salmonella Assays
Reported by the Veterinary Diagnostic Laboratory at
the Pennsylvania State University.
Ingredient No. Samples % Positive
Animal Protein 62 63
Distillers Grains 51 0
Canola Meal 11 18
Oats 15 7
Soybean Meal 20 20
Adapted from John, R.E., 1990. Proc. Symp. Feed
Quality Assurance, Centre for Veterinary Medicine,
USDA, Arlington, VA.
These results compare to a survey offive feed
compounders conducted by the United Kingdom
Ministry ofAgriculture, Food and Fisheries (Table
11-4).
Table 11-4. Survey of Raw Materials Provided by
Five Feed Compounders in the U.K.
Ingredient No. Samples % Positive
Barley 42 0
Com 18 6
Fats 31 3
Feather Meal 23 0
Fish Meal 44 9
Meat and Bone Meal 46 7
Peas 30 0
Soybean Meal 46 7
Wheat 51 6
Adapted from John, R.E., 1990. Proc. Symp. Feed
Quality Assurance, Centre for Veterinary Medicine,
USDA, Arlington, VA.
235

254. Fungi and Mycotoxins
Fungi impair feed quality in at least two ways.
They may alter the nutritional quality of feeds by
destroying or making unavailable important nutri-
ents such as vitamins or they may produce
myeotoxins that are harmful to the pig.
The direct effect on nutrient composition is
difficult to predict and attempts have failed to
demonstrate impaired pig performance due solely to
fungal growth. Documented cases offeeding
extremely moldy corn to swine without difficulty
demonstrate that mold by itselfprobably represents
only minimal risk to the pig. It is not until the fungi
produce mycotoxins that animal performance
suffers. Some toxins need only be present in very
small concentrations to affect pig health.
While it would be useful to have tables summariz-
ing maximum tolerances for the various toxins of
importance in swine production, the reality is that
such tables are very difficult to produce. The
maximum tolerance for any particular toxin will be
affected by many factors, including the response
criteria (animal performance versus tissue damage),
time frame (short-term versus long-term effects)
and, interestingly, the nutrient specifications ofthe
diet. For example, some toxins are involved in the
metabolism ofhighly toxic compounds called free
radicals; protection from free radicals is obtained by
consuming increased quantities ofantioxidants,
such as vitamin E. Consequently, the toxic level of
certain mycotoxins will vary, depending on the
vitamin E level of the diet.
Another problem in determining the toxicity ofa
moldy grain sample is the occurance of multiple
toxins, some ofwhich may be present at low levels
or which are difficult to identify. While the toxin(s)
assayed may be below tolerance, associated toxins
which may not have been measured may contribute
to the overall toxicity ofthe sample. This is a
particularly troubling aspect ofmycotoxin technol-
ogy, since there are literally dozens of toxins known
to man and one cannot practically assay them all!
The molds ofgreatest interest in Canada and the
United States areAspergillusjlavus which produces
aflatoxin, and Fusarium roseum which produces
zearalenone and vomitoxin. Several other fusarium
varieties also produce toxins while Penicil/ium and
Aspergillus produce ochratoxin. These are ex-
plained in detail later in the chapter.
Ergot
Ergot alkaloids are very potent toxins produced
by the fungi ergot (Clavicepspurpureay. Triticale
and rye are the most susceptible grains, but wheat,
barley, oats and corn can also become infected.
Visual inspection ofsuspect grain is useful, since
the infected kernels are usually dark, swollen and
have a rough coat. Once the grain is ground,
detection requires laboratory analysis.
Ergot alkaloids can severely affect pig health and
performance. They impair blood flow to the
extremities, affecting tissues such as the kidney and
uterus. Reduced blood flow to the reproductive
tissues can result in spontaneous abortion in poi-
soned sows. In fact, in ancient times, abortions in
humans were induced by feeding ergot. Piglets
born to infected sows have poor viability, due to
impaired lactation ofthe dam.
Poor blood flow also explains other symptoms of
ergot toxicity such as blackening of the tips ofears
and sloughing ofhooves. In these examples, poor
blood flow actually results in the death ofthe
respective tissue. Ergot poisoning can also reduce
feed intake, induce convulsions and muscle incoor-
dination, cause respiratory distress and precipitate
an outbreak ofdiarrhea.
At the present time, only imprecise recommenda-
tions on ergot are available. Suspect grains should
never be fed to breeding animals and the quantity of
contaminated kernels fed to growing pigs should
not exceed 0.1% ofthe total grain in the ration (one
infected kernel for every 1000 clean kernels).
Ochratoxin A
Ochratoxin affects the kidneys in swine. Post
mortems of infected pigs reveal swollen kidneys
which are lighter in colour and firmer than healthy
kidneys. Ochratoxin can cause birth defects when
sows are infected and impairs growth in market
236

255. hogs. Swollen kidneys will occur at levels much
lower than those required to impair performance.
lmmunosuppression has also been associated with
Ochratoxin A.
Ochratoxin infects many crops including barley,
oats, wheat, com and soybean meal. It is produced
by the fungi Aspergillus and Penicillium and is
generally restricted to areas oftemperate climate
such as those found in the southeastern United
States. Safe levels ofochratoxin for swine have not
been defined, although it is known that weanling
pigs fed 28 ppm ochratoxin will die within three
weeks.
Zearalenone
Zearalenone, sometimes referred to as F2 toxin, is
a mycotoxin produced by the fungi Fusarium. It is
often associated with corn but can infect many other
crops including wheat. It is an estrogenic com-
pound; as a result, its effects on the pig are similar
to those ofthe natural hormone, estrogen. Estrogen
particularly affects reproduction and consequently,
most research on zearalenone bas been carried out
on sows and gilts, with less information being
available on growing pigs. Pigs, as a species, are
particularly susceptible to zearalenone toxicity.
Levels between 1 and 5 ppm are sufficient to elicit a
number ofestrogenic symptoms.
SYMPTOMS OF
ZEARALENONE TOXICITY
-swollen vulvas in gilts
-vaginal or rectal prolapse
-swollen mammary tissue
-reduced testicle size in young boars
-shrunken ovaries in gilts
-enlarged uteruses
-infertility
-abortion
-reduced litter size
-birth of small, weak piglets often
suffering from spraddle leg
Photo ll-1a.
Aborted and mummified piglets.
Photo 11-lb.
..Rectal prolapse.
The effect on neonatal piglets depends on when
the infected feed was eaten. Ifconsumed in late
pregnancy, the incidence of stillbirths and spraddle
leg is increased. [f eaten in mid-pregnancy, only
spraddle leg increases. If the zearalenone is eaten in
early pregnancy, litter size (total number of piglets
born) is reduced, but no affect on spraddle leg
conditions or stillbirths is detected.
237

256. Zearalenone can also be carried in the sow's or
gilt's milk and thus affect the growth rate of new-
born piglets. Up to 30 ppm ofpure zearalenone
appears to have a minimal effect on litter size in
gilts while levels of 60 to 90 ppm result in the
complete loss of fetuses. The impact of
zearalenone remains with gilts for many months
after the infected diet is removed.
Zearalenone appears to also affect boars. lt
reduces libido (sex drive) and delays sexual matu-
rity in growing boars. However, diets containing up
to 60 ppm zearalenone have no apparent effect on
semen quality or libido of mature boars.
The effect ofzearalenone on growth is less clear.
Some experiments have demonstrated that as little
as lO ppm ofzearalenone depresses pig growth and
appetite. Other experiments suggest that there is no
effect on growth at levels of toxin as high as 50
ppm. There is even the suggestion that growth is
actually enhanced by zearalenone. Part ofthe
problem with the variable responses produced by
zearalenone may be due to contamination of the test
ingredients with other toxins such as vomitoxin.
Vomitoxin is known to impair performance and is
often found in samples ofgrain contaminated with
zearalenone.
Tricothecenes
Tricothecenes are a group ofvery toxic com-
pounds which include deoxynovalenol (also called
DON or vornitoxin), HT-2 toxin,
diacetoxyscirpenol and T-2 toxin. They are pro-
duced by Fusarium molds and are very toxic to
pigs. T-2 toxin is unique in that it forms during
storage at low temperatures (6 - l 8°C).
One feature oftricothecenes that is particularly
troubling is its suppression ofthe immune system.
Even low levels in the diet may increase the pig's
susceptibility to pathogenic organisms that normally
would not create health problems. Studies with
contaminated wheat indicate that as little as l ppm
vomitoxin reduces feed intake and growth rate in
market hogs. Levels in excess of20-40 ppm cause
vomiting and feed refusal. One of the most striking
features of DON contamination is feed refusal.
Vornitoxin contaminated feed does not appear to
affect reproductive performance in gilts. Levels up
to 8 ppm vomitoxin did not produce adverse results
with regards to reproduction. Since vomitoxin is
often found in grains containing zearalenone, it is
difficult to determine which of these toxins is
causing a given problem. From research to date, it
appears reproductive impairment is most likely due
to zearalenone and not to vomitoxin contamination.
Other trichothecenes may be even more toxic than
vomitoxin. They cause feed refusal, vomiting,
irritation ofthe skin and the gut and may also result
in the birth ofdeformed piglets. One to JO ppm
diacetoxyscirpenol will reduce growth rates. Diets
containing 8 ppm T-2 toxin do not affect weight
gains but increasing levels to 16 ppm will depress
growth rate.
Aflatoxin
Aflatoxin is produced primarily by the fungus,
Aspergillus. Ideal conditions for Aspergillus growth
include moisture content above 14%, temperature
above 25°C and the presence ofoxygen. It is
known to affect many feed ingredients including
corn, rye. oats, wheat, barley, soybean meal, sun-
flower meal, rapeseed and alfalfa. There are four
types of aflatoxin: B1
, B2
, G1
and G�. Aflatoxin B1
is considered to be the most potent for swine.
The impact ofaflatoxin on swine is age and dose
dependent, and ranges from depressed perfonnance
through immune suppression. Acceptable upper
limits have been defined by various agencies; for
young pigs, levels in excess of20 ppb should be
avoided, for finishing swine, the limit is 200 ppb
and for breeding animals, the limit is l00 ppb.
Recovery from aflatoxin toxicity is rapid in grow-
ing pigs. Seven days on clean feed will usually
result in a full recovery. In younger pigs, scouring
can result from aflatoxin poisoning. In sows, milk
production is impaired.
238

257. Prevention of Mycotoxin
Contamination
Since effective treatment methods have not been
developed, prevention of mold contamination is
very important. Cropping practices can play a
useful role in prevention. Rye and triticale are
examples ofcrops that are particularly susceptible
to ergot. The selection of more resistant grain
varieties is a major consideration. Late maturing
com may provide greater yields but the seeds are at
a susceptible stage ofdevelopment during the wet
weather that often occurs in the late summer and
fall. Crop rotation can help break the life cycle of
infecting spores. Com and wheat can be rotated
with less susceptible crops. Profitability in the short
term may be reduced. but this must be compared to
the long-term benefits. Researchers have also
observed that scabbiness caused by Fusarium
molds, especially in wheat, can be reduced by
fertilizer selection. The use ofurea fertilizer in
place of ammonium nitrate can be helpful.
Fusarium infestation is favoured by warm (15°C-
350C), windy, rainy weather. These conditions
provide an excellent environment for infecting
spores to spread. Therefore. this kind ofweather
during late growth and harvest should raise con-
cerns about potential contamination.
Once grains are harvested, other practices can be
beneficial. The cleaning ofgrains to remove
damaged kernels will help to remove sources of
infestation. Broken kernels and related material
often contain the highest concentration of
mycotoxins. Their removal greatly improves the
feeding value of the grain. The addition ofmold
inhibitors will not kill mycotoxins already present
but will prevent further formation.
'Water activity' is an important factor influencing
mold growth and mycotoxin production in grain. It
differs substantially from simple moisture content
because it also takes into consideration ambient
temperature and the nature ofthe grain. These three
conditions determine the susceptibility ofthe grain
to mold growth. It is important to keep water
activity below 0.75, which means keeping both
moisture and temperature as low as is practical. If
ambient temperatures are expected to rise as high as
32°C, moisture in corn must be kept below 13% to
prevent mold from growing. At 21 °C, moisture can
rise to 15% before there will be a problem. In
soybean meal, moisture should be kept below 14%.
In summary, it is important to recognize that mold
contamination ofgrains can occur at many stages:
during growth, at the time ofharvest, during storage
as seed or after being processed into livestock feed.
Field contamination is worse when kernels are
damaged, when the weather conditions are moist or
if insects infest the crop. The satisfactory storage of
grains or mixed feeds requires low moisture levels
and temperatures as cool as possible.
Treatment
Ifgrain contamination is suspected, samples
should be submitted to a laboratory for analysis.
Increasing numbers of labs are setting up to conduct
mycotoxin analyses. It is a difficult analysis due to
the sophisticated tests required and also due to
problems with sampling. A heavy infestation of
only a small portion ofa field of com can result in
swine diets contaminated above acceptable limits.
Ifsampling failed to include the contaminated area
ofthe field, tests would be falsely negative.
Ifgrains are suspected ofbeing infected, a sample
can be fed to a group ofyoung gilts. If swelling or
reddening ofthe vulva appears or iffeed intake is
impaired, contamination should be suspected. The
infected grain should not be fed to breeding animals
Accumulation of water or wet feed in augers, feed
trucks.or storage bins can lead to rnycotoxin contamina-
tion of feeds.
239

258. and if it is fed to market hogs, it should be diluted
as much as possible with "clean" grain.
Chemical treatments of infected grains are being
investigated. It has been shown that sodium
bisulphite added to infected corn and then
autoclaved can reduce DON (deoxynovalenol or
vomitoxin) concentrations by a factor of I 0. To
date, this is not commercially practical, because
autoclaving is slow and expensive. However, other
heating processes may prove to be as beneficial.
Another possibility is the addition of hydrated
sodium calcium aluminosilicate (HSCAS) to diets
containing vornitoxin and/or zearalenone. Prelimi-
nary results suggest that there may be some value in
the use ofsuch products, although more research is
required.
Ifmild contamination is suspected, the nutrient
density ofthe diet can be increased to help compen-
sate for reduced intake. The vitamin, mineral and
amino acid concentrations should be increased by
5-20% depending on the severity offeed refusal
expected.
Safety
Molds and mycotoxins can also be harmful to
humans. Symptoms include allergies, skin and eye
irritation, headaches and vomiting. Fusarium
spores are a well-known toxin and must be avoided.
Aspergillus poisoning has also been recorded. If the
grain must be handled, ventilation is important and
the use ofgloves and respirators is advised.
If contaminated grain must be handled, gloves and
rcpirators should be used.
Additional Reading and References
Anon. 1987. Recent developments in the study of
mycotoxins. Kaiser Chemical Co., Cleveland, OH.
Cheeke, P.R. and LR. Shull. 1985. Natural
toxicants in feeds and poisonous plants. AYINon
Nostrand Reinhold Co., New York. 492 pp.
d'Mello, J.P.F., C.M. Duffus and J.H. Duffus.
1991. Toxic substances in crop plants. The Royal
Society ofChemistry, Cambridge. 339 pp.
Marquardt, R.R. 1993. Effects of moulds and their
toxins on livestock performance: A western Cana-
dian perspective. Proc. Western Nutrition Conf.,
Winnipeg, MB. pp. 115 - 121.
Trenholm, H.L., D.B. Prelusky, J.C. Young and J.D.
Miller. 1988. Reducing mycotoxins in animal
feeds. Publication #1827E, Agriculture Canada,
Ottawa, Ontario.
240

259. 12. WATER
Like other nutrients, such as energy and essential
amino acids, water is an absolute requirement in the
diet of the pig. Lndeed, the pig can survive much
longer without energy or protein, minerals or
vitamins than it can without water. This is espe-
cially true in hot weather.
Water fulfils many functions in the pig. It pro-
vides the liquid environment that supports the
movement of nutrients, waste products and hor-
mones throughout the body. Water helps the pig
maintain constant body temperature and acid-base
balance, and it is a critical part of many essential
chemical reactions.
Water makes up about 80% ofthe total body
weight ofthe newborn piglet; this declines to about
50% in adult swine because ofthe lower water
content in fat as compared to muscle tissue.
Pigs derive water from three sources: water
physically contained in the feed, water consumed by
drinking and waterproduced by normal metabolism
in the body. Figure 12-1 illustrates typical sources
and fates of water in a young growing pig; under
varying environmental, nutritional and behavioural
circumstances, actual values could differ signifi-
cantly from this example.
Input.
·-...
Output.
Figure 12-1. Water balance in the pig: intake and
output.
Requirements and Intake
The water requirements ofthe pig have never
really been defined. In part, this is due to the
assumption that pigs will drink when they need
water and all that is required is an adequate delivery
system. There seemed little point in spending
money on research that would provide little appar-
ent economic benefit!
The relative absence of research defining the pig's
requirement for water is also due to the fact that
such investigations are extremely difficult, and
cannot be accomplished in the same way that one
defines the requirements for other nutrients. The
response criteria employed for defining amino acid
or energy requirements do not apply to water. Also,
a wide range ofenvironmental factors, such as
temperature and diet composition (mineral levels,
protein content) influence requirements.
In the absence oftraditional requirements, studies
ofactual water intake have been used to help
predict the water requirements for a given produc-
tion unit. Measuring water consumption accurately
is not an easy task. Simply placing a water meter in
241

260. the drinker line overlooks two important problems:
the amount of water wasted and the inaccuracy of
most meters at very low or intermittent flow rates.
Waste can represent a significant portion oftotal
water "disappearance." With nipple drinkers, waste
can reach 50% or more of intake and will be even
higher when boredom or other stressors are present.
Much ofthe earlier information published on water
intake failed to measure waste and must be inter-
preted with great care.
Research at the Prairie Swine Centre and else-
where has found that true, free choice water intake
in young growing pigs fed ad libitum is about 2.2 to
2.8 times the intake offeed. Thus, a pig eating 2 kg
of feed will normally drink at least 4.5 litres of
water per day.
underestimated; boredom and hunger can increase
water intake many fold over basic requirements.
The obvious question relates to the importance of
over-consumption. ls it a problem? For the most
part, we do not believe that it is, in terms of pig
health or productivity; any water consumed above
requirement will be eliminated as urine. However,
over-consumption does waste water and perhaps
most critically, increases the cost ofslurry storage
and spreading. Excess water intake, and more
importantly, direct water waste is a growing con-
cern; the cost ofslurry storage is rising in response
to environmental concerns and the expense of
spreading slurry is also increasing due to higher
labour and fuel costs.
INCREASE
Hunger
Boredom
Heal stress
Increased dietary minerals
Moderate mineral levels
in water
Pelleted feed
DECREASE
Cold stress
Warm water
temperature
High mineral levels
in water
Is under-consumption a problem? There is an
increasing body ofdata which strongly suggests that
even under ad libitum conditions, pigs do not
always drink as much water as they require for good
health and maximum performance. Clearly, more
research is needed, but the implication is that
providing water free choice may not always ensure
optimum intake.
Gestating Sows
Water use by gestating sows is affected by both
physiological need and behavioural influences.
Since dry sows are limit fed, they consume addi-
tional water to help achieve a feeling ofsatiety (full
stomach). This additional intake has little to do
with "requirements" as defined in the classical
sense, but may be important to the sow's achieving
an overall sense ofwell-being. For example, in
human nutrition, it is not uncommon to recommend
that people on diets consume additional water, in
part to help achieve a sense ofsatiety.
In addition, dry sows are often housed in indi-
vidual gestation stalls, where boredom is common.
Sows will consume additional water, and play with
drinkers more often, merely to offset this sense of
boredom. This additional water intake and playing
with drinkers may lead to excessively wet, dirty
conditions in the barn, depending on the design of
the stalls. If it is a problem, providing water in the
feeding trough, rather than nipple drinkers, has
242
Pigs do not drink solely to satisfy their
physiological need for water. They will also drink
water to alleviate a feeling of hunger or boredom.
The impact of"luxury" intake must not be
Additional water, to compensate for elevated
environmental temperature or excess mineral or
protein in the diet, or to help the pig deal with
certain health problems. must be added to the above
intake levels. It is difficult to define water intake at
high barn temperatures, since much ofthe reported
research measured water disappearance, which
includes waste, rather than actual intake. Actual
intake probably rises by only 15% to 75% in hot
weather, but waste increases dramatically, such that
total water disappearance from nipple drinkers
might increase as much as 3- to 4-fold. Following
are some ofthe factors that increase or decrease
water consumption.

261. proven helpful. The provision of small amounts of
straw, to serve as an object offoraging, or the
feeding of a bulky diet have also proven helpful in
minimizing excessive drinking.
Providing water in a properly-designed trough
which minimizes waste and spill is an ideal method
for providing water to the dry sow. In the case of
nipple drinkers, firm recommendations are not yet
available, but flow rates of0.5 L/minute will more
than suffice.
Lactating Sows
All things being equal, lactating sows have the
highest relative requirement for water, due to the
demands ofmilk synthesis. Intake studies under ad
libitum conditions have suggested that nursing sows
will drink between 9 and 20 litres of water per day.
This is a very large variation and reflects the tre-
mendous differences one sees among animals.
Well-controlled experiments, where wastage is
accurately measured, reveal that the majority of
sows will drink about 15 litres per day.
However, provision of water ad libitum may not
be enough to ensure optimum intake. Drs. Fraser
and Phillips at the former Centre for Food and
Animal Research in Ottawa have studied water
intake in newly-farrowed sows and found that litters
tended to gain poorly during the first three days
after birth ifthe sow drank less than 10 litres of
water during this period. The researchers concluded
that in some sows, poor early lactation performance
is associated with very low water intake. This low
water consumption may be a symptom of other
health problems, orjust a case of simple lethargy on
the part ofthe sow. Until more information be-
comes available, it may be prudent to encourage
sluggish sows to become active as soon after
farrowing as possible to stimulate drinking and thus
promote better early lactation performance. Placing
nipple drinkers at different heights in the farrowing
crate docs not appear to alleviate the problem.
How should water be provided to the lactating
sow? In early lactation, lethargy is a problem in
some animals and the best way to maximize the rate
of consumption is to provide water troughs. While
this is not practical in most situations, placing water
in the feeder for the first three to four days after
farrowing, for those few sows who do not appear to
be drinking or eating well, may be advised.
Beyond day three, when this initial adjustment
period ofearly lactation has passed, nipple drinkers
with flow rates between I and 2 L/minute, will
suffice. While some recommendations exist for
much higher flow rates, research at the Centre for
Food and Animal Research in Ottawa suggest no
such advantage exists; the only real effect is greatly
increased wastage with attending problems and
costs. Indeed, the few studies which have shown
impaired lactation performance required flow rates
well below 0.5 L/minute!
Some suggestions have been made that sows will
spend no more than five to six minutes drinking
water per day; this may be true for a few sows
during the first two to three days after farrowing,
but is clearly not the case for most sows and cer-
tainly not beyond the third day of lactation. Re-
search has shown that sows will spend 15 minutes
or more per day at the drinker.
Excessive flow rates will not only waste water,
but will also result in messy crates and wet piglets.
For this reason, addressing the issue of lethargic
sows by adding water to the feeder for those few
animals in difficulty is a more practical and eco-
nomical solution.
Piglets
Recent research, again by Ors. Fraser and Phillips,
suggest that piglets may require water immediately
after birth. They reported that litters gaining poorly
during the first one to three days after farrowing
drink more water than faster growing litters. It has
been suggested that when sows are not milking
well, piglets may not consume enough water from
their limited milk intake and might benefit from
supplemental drinking water. Nipple drinkers are
not adequate for newborn piglets, because the
piglets take too long to find and use the drinker; a
dish drinker, located in the creep area, is a better
alternative. Balancing cost and convenience,
portable dish drinkers may be the best choice,
243

262. Table 12-1. Nipple Drinker Flow Rates on
Saskatchewan Farms.
A relatively recent variation is the wet/dry feeder
which incorporates a nipple drinker inside the
feeder bowl; in some respects, they combine the
features ofnipple and dish drinkers. Since in some
circumstances they increase feed intake, wet/dry
feeders are increasing in popularity. They also
reduce water wastage; a Manitoba study by Froese
and Hodgkinson found that water usage was re-
duced by 40% with the use ofwet-dry feeders.
4.6
4.4
3.9
% below 0.5
(mUmin)
65 1.55
68 1.34
77 1.52
No. Ave. flow rate
farms (mlJmin)
Several studies have demonstrated that restricted
nipple-drinker flow rates can impair water intake
and, under severe restriction, growth rates as well.
However, the flow rates must be quite low - prob-
ably below 200 mL/min. A recent survey of Sas-
katchewan farms revealed typical flow rates that
greatly exceed this minimum (Table 12-1 ). These
data suggest that excessive flow rates, leading to
wastage, may be more ofa concern than inadequate
flow rates. However, individual nipple drinkers still
need to be checked regularly to ensure against
blockage or malfunction.
Farrowing
Weanling
Growout
Water Delivery
Nipple drinkers are by far the most common
method ofproviding water to pigs. They are of
relatively low cost, easy to maintain and generally
free of fouling. However, nipple drinkers do have
their problems. They encourage waste and cannot
be easily monitored; often, it will be many hours or
even days before a plugged drinker is noticed, if
daily checks are not observed. Nonetheless, nipple
drinkers are probably the method ofchoice for the
time being for all classes ofswine except newborn
piglets, where dish drinkers are clearly superior.
Location
Some people have asked ifthe provision of
drinking water to very young piglets may be harm-
ful, reducing their motivation to suckle. A number
ofstudies have clearly indicated this is not the case.
Consequently, providing water to newborn piglets,
although not a common practice, is strongly recom-
mended, especially in warm conditions where
piglets lose moisture rapidly.
One common belief is that providing water to
nursing piglets encourages creep feed intake.
Although this may be true, studies have shown that
the effect is relatively small until the pigs are four to
five weeks of age.
employing them only in newborn litters where sow
milk production appears to be a problem.
Weanling Pigs
At the time of weaning, pigs are suddenly re-
quired to obtain aU oftheir water from the drinker.
It is not altogether clear how well the newly-weaned
pig can regulate water metabolism, or select a daily
intake appropriate to its needs. For example, a
number ofexperiments have shown that water
intake follows a peculiar pattern at weaning, being
initially quite high, falling to a minimum at about
four days post-weaning, followed by a gradual
increase as feed intake rises. Surprisingly, water
intake is at its lowest when scouring is typically at
its worst, raising questions as to the adequacy of
water intake at this time.
Figure 12-2. Typical Water Intake Pattern During
the Post-weaning Period. Source: 1990 Prairie Swine Centre Annual Report
244

263. Table 12-3. Canadian Water Quality Guidelines for
Livestock.
such as the age or health status affect the response
of individual animals.
The critical question for pork producers is what
are the minimum and maximum flow rates neces-
sary to optimize health and productivity? Unfortu-
nately, research on the subject is extremely limited;
in the absence ofdefinitive experimental data,
estimates are the best that can be provided. For
weanlings and growers, flow rates between 500 and
1500 mL/min would appear to be satisfactory. For
nursing sows, flow rates between 1000 and 2000
mL/min should cause little problem. In all cases,
the major impact of excessive flow rates will be
excessive wastage.
Table 12-2. Recommended Nipple Drinker Flow
Rates for Various Classes of Swine.
Item
Major ions
Calcium
Nitrate+ nitrite
Nitrite alone
Sulphate
TDS
Maximum Recommended
Limit, ppm
1,000
100
10
1,000
3,000
I
Estimates only, as exact ranges have yet to be com-
pletely defined.
Liquid feeding, whereby water and feed are
presented to the pig as a preformed mixture. offers
an alternative to separate feeders and waterers.
Although the primary objective of liquid feeding is
to increase feed intake, reducing water waste may
be a notable additional benefit. Normally, a
water:feed ratio of2.5: l is utilized in liquid feeding
systems; this may change slightly with the make-up
ofthe diet, the class ofswine being fed and the
environmental conditions within the barn.
Recommended
Flow Rate, mL/min1
Heav)'.'. metals and trace ions
Aluminum 5.0
Arsenic 0.51
Beryllium 0.12
Boron 5.0
Cadmium 0.02
Chromium 1.0
Cobalt 1.0
Copper (swine) 5.0
Fluoride 2.03
Iron no guideline
Lead 0.1
Manganese no guideline
Mercury 0.003
Molybdenum 0.5
Nickel 1.0
Selenium 0.05
Uranium 0.2
Vanadium 0.1
Zinc 50.0
Source: Adapted from Task Force on Water Quality
Guidelines, 1987.
1,000
2,000
1,000
1,000
Minimum Maximum
500
1000
750
750
Gestation
Lactation
Weanling
Growout
Class of Swine
Water Quality
There are essentially three major criteria for
evaluating water quality: microbiological, physical
and chemical. Within each, individual items relate
to safety and/or asthetics. Canadian Federal Water
Quality Guidelines appear in Table 12-3. Such
standards must be interpreted with caution. Al-
though they provide a useful general tool, they must
not be considered definitive, because other factors
The most common chemical analyses are listed in
Table 12-4. Two schedules are provided: the
primary test provides a useful overview and should
be the first step in characterizing a water sample. If
no problems are detected, there is no value in
proceeding to the secondary tests, which are more
comprehensive - and expensive. This approach
combines economy and efficiency and helps focus
attention on those issues of true importance.
245

264. Primary Test
Total Dissolved Solids
pII
Iron
Hardness
Nitrates/nitrites
Supplementary
Test
Sulphates
Sodium
Magnesium
Chloride
Calcium
Potassium
Manganese
pH
pH is rarely a concern because the vast majority
ofsamples fall within the acceptable range of6.5 to
8.5. If elevated, pH impairs the efficiency of
chlorination; low pH may cause precipitation of
some medications delivered via the water system.
This could lead to carcass residues ofthese same
drugs, ifthe precipitate is later carried in the water
to pigs nearing market weight.
Hardness
Hardness is caused by multi-valent metal cations,
the most abundant in groundwater being calcium
and magnesium. Although it has no effect on
animal health, hardness does impair the cleansing
ability ofwater and also results in the accumulation
ofscale in water delivery and treatment equipment.
Thus, hardness can lead to problems associated with
inadequate water supply ifnipples, filters, etc.
become plugged. Water is considered soft if
hardness is below 50 ppm; if above 300 ppm, it is
deemed very hard.
Chloride
Chloride is not commonly elevated in
groundwater on the Prairies. Ifchloride, as sodium
chloride (salt), is elevated. it can be countered by
adjusting the salt content offeed; this must be
carried out by a qualified nutritionist to avoid
problems.
Table 12-4. Assays to Include in the Chemical
Evaluation ofWater Used in Pig Production.
All minerals elevate TDS. but only a few cause
health problems; for example, calcium and magne-
sium contribute both to hardness and TDS, but
unless present at extremely high levels or in associa-
tion with sulphate, have no adverse effect on pig
health. Sulphates, a major contributor to TDS in
some regions, can result in severe diarrhea at even
moderate levels. One can conclude that ifTDS is
low, the water is ofgood quality. lfTDS is moder-
ate to high, it may still be perfectly safe to drink.
depending on what minerals are responsible. For
this reason, ifTDS is above 1000 ppm, the supple-
mentary tests are required to determine ifthose
minerals responsible for the high reading represent a
significant health risk to the pig.
Total Dissolved Solids
Total dissolved solids (TDS) measures the sum of
all inorganic matter dissolved in a sample of water.
Tfless than 1,000 ppm, there is little concern. If
greater than 7,000 ppm, it is unfit for swine. Be-
tween 1,000 ppm and 7,000 ppm, some farmers and
veterinarians report economically relevant losses.
Sometimes, the water with a high level ofTDS is
called "hard." This is incorrect, as hardness and a
high mineral content can be quite different.
Conductivity
Conductivity may be used as a predictor of
overall water quality in place ofTDS. Multiplying
conductivity by a constant is used to estimate TDS;
however, the value of this constant differs among
types of water, so that such conversions must be
viewed with discretion.
Iron
Low levels ofiron, as low as 0.3 ppm, can cause
brownish-coloured stains in laundry and bathroom
fixtures. Normally, iron in ground water exists in
the soluble form; when pumped to the surface and
exposed to oxygen, the iron in the water becomes
insoluble. The consequence ofall this is the pre-
cipitation of iron when water is pumped from the
well, leading to possible blockage ofthe delivery
system. In such cases, iron filters or a settling tank
(Table J 2-5) can be used to remove the iron before
it becomes a problem.
246

265. Table 12-5. Effect ofAeration and Seven Days
Settling on Water Chemistry (mgfL).
Item Dai
0 7
pH 7.92 8.06
ms 2388 2378
Hardness 761 760
Alkalinity 408 405
Sulphates 1268 1248
Sodium 446 432
Calcium 183 189
Magnesium 75 72
Chloride 40 45
Potassium 10 11
Nitrates L.0 1.0
Nitrites 0.3 0.3
Iron 2.5 0.6
Source: Tremblay et al., Prairie Swine Centre Annual
Report, 1989.
Iron in the water can also support the growth of
iron bacteria, ifthe well has been contaminated;
however, not all wells with iron in the water will be
contaminated with iron bacteria. Iron bacteria can
cause foul odours and in extreme cases, can actually
plug water systems, including the well itself. Such
foul odours and blockage is caused by the accumu-
lation ofdead and decaying bacteria.
Shock chlorination may solve the problem, but in
many cases, the benefits are temporary and the
procedure may need to be repeated on a regular
basis. One method is to mix 25 L of household
bleach with 900 L of water; this mixture is poured
into the new well and left there overnight. If
necessary, the chlorinated water can be drawn
through the pipes by turning on a tap at the farthest
location from the well. Such water cannot be
consumed, so all waterers must be turned off until
the system is thoroughly flushed the following day.
Magnesium
Magnesium sulphate, also known as Epsom salts,
is undesirable in water because ofassociated
diarrhea. Typical water analysis will not define the
amount of Epsom salts present, only the amount of
magnesium and sulphates present. As mentioned
above, magnesium, along with calcium, is also used
to calculate total hardness.
Sodium
Sodium sulphate, also know as Glauber's salts, is
a laxative and cathartic agent. By themselves,
magnesium and sodium normally pose little risk to
the pig, but their association with sulphate is a
major concern.
Manganese
Like iron, manganese can also cause staining of
laundry and bathroom fixtures. The threshold level
ofmanganese is 0.05 ppm. Like iron, manganese
exists in groundwater in the soluble form and is
precipitated only when pumped to the surface.
Nitrates
Many people are concerned about nitrates and
nitrites in their water. For human infants, their
concern is well-founded since nitrates can be a
serious problem. The primary concern relates to the
reduction in the oxygen-carrying capacity ofthe
blood. Among livestock, cattle are more suscepti-
ble to the problem than pigs, because the bacteria in
the rumen convert nitrate to the much more danger-
ous nitrite.
Nitrates are often a man-made problem. They are
formed by the decomposition oforganic material,
and can percolate through soil and into a well at up
to 1 metre (3 ft) per day! They are also persistent.
Examples ofbarns tom down three decades earlier
still causing nitrate problems have been
documented.
Nitrates as well as nitrites in the water have been
shown to impair the utilization ofvitamin A by the
pig and reduce overall animal performance. llow-
ever, the levels required to affect performance were
so much greater than observed in most water that
there is little cause for concern under practical
conditions. Although pork producers should be
cognizant ofthe potential hazards of nitrates to
livestock, they pose a greater risk to humans who
consume contaminated water.
247

266. Sulphates
Sulphates arc a primary source ofproblems
associated with well water quality. Sulphates are
not well-handled by the gut of the pig, resulting in
diarrhea and possibly reduced performance. Wean-
ling pigs are most susceptible, but in severe cases,
even adult sows have been afflicted. Depending on
the level of sulphate in the water, pigs can adapt and
over a period ofa few weeks, become accustomed
to the water. This may explain why pigs at weaning
appear to be most susceptible, since prior to wean-
ing, they have likely consumed very little drinking
water.
Impact ofWater Quality
What effect does poor quality drinking water have
on pigs? Diarrhea is certainly the major concern,
especially in the weanling pig (adult swine may be
effected in severe cases); the impact ofwater
quality on animal performance remains
controversial.
Clinical reports suggest a major impact ofpoor
quality water on animal performance on some
farms. Yet, this has not been supported by control-
led research, which has consistently concluded that
pigs have considerable ability to handle water of
widely varying quality with no effect on perform-
ance. The observation ofdiarrhea associated with
poor quality water has never been questioned; the
impact on pig performance has.
How does one proceed? The results ofexperi-
ments summarized on Tables 12-6 to 12-8 provide
useful information. Tn the first experiment (Table
12-6), pigs received either good quality water or
one oftwo samples obtained from local farms; in
all cases, the pigs pcrformed very well, despite the
fact that sulphate was as high as 2650 mg/L.
Table 12-6. Effect ofWater Quality on the
Performance ofWeanling Pigs Fed a Diet Containing
Antibiotics.
TDS <m2m)
Variable 217 2350 4390
Water quality, ppm
Sulphates 83 1280 2650
Calcium 24 184 288
Chloride 8 34 70
Magnesium 15 74 88
Sodium 24 446 947
Hardness 124 767 1080
pH 8.4 8.1 8.0
Performance
Avg daily gain, kg/day 0.43 0.43 0.44
Avg daily feed, kg/day 0.55 0.56 0.57
Feed:gain 1.28 1.31 1.30
Avg daily water, kg/day' I.60 1.84 1.81
Scour score1
1.07 l.30 1.46
NB. Pigs were weaned at 28 days ofage and immediately
placed on test for 21 days; feed and water were offered
free choice. Source: McLeese et al. 1991.
1
Effect ofwater source significant, P<0.05.
In the second experiment (Table 12-7), the starter
diet did not contain any antibiotic, and in this
instance, the pigs on the poor quality water grew
slower and less efficiently than those on the good
water. Finally, when pigs were given either good or
poor quality water and exposed to either a normal
or chilled environment (Table 12-8), the cold stress
did not appear to make the pigs more susceptible to
the effects ofthe water. In fact, pigs actually grew
better on the poor quality water, apparently due
primarily to increased feed intake!
248

267. Table 12-7. Effect ofWater Quality on the Perform-
ance ofWeanling Pigs Fed a Diet Free ofAntibiotics.
Table 12-8. Effect of Pen Temperature and Water
Quality on the Performance of Newly-weaned Pigs.
NB. Pigs were weaned at 28 days and immediately placed
on test for 21 days. Feed and water were available free
choice. Source: Mcleese et al., 1991
1
Effect ofwater significant, P< 0.05)
Environment Water Quality
Normal Chilled Good Bad
Response to Poor Quality Water
ln response to water problems, some changes to
the diet might be warranted. These must always be
carried out with great care. Following are some
changes that are commonly adopted in response to
water problems.
Dietary Salt Reduction or Removal
This is a common practice on farms using water
containing a high mineral load. Partial removal of
salt can almost always be done without fear of
difficulty because most diets contain a reasonable
safety margin. However, complete removal of salt
from the feed must be done with great care, because
removing dietary salt removes both sodium and
chloride. While most water that is high in sulphate
often contains high levels ofsodium, the chloride
content ofwater on the Prairies is usually very low.
Consequently, removing too much salt from the
feed could result in a chloride deficiency. There-
fore, careful water analysis must attend any adjust-
ment ofdietary salt levels. Furthermore, ifsalt
adjustment is employed, water analysis must be
repeated on a regular basis to ensure that the min-
eral content ofthe water has not changed.
0.360
0.521
1.47
4390 ppm
960 1671
1848 2428
7382 9878
434 639
T.D.S.
1057
2170
7628
366
0.418
0.530
1.33
217 ppm
1574
2106
9632
708
Avg gain (kg/day)
Avg feed intake (kg/day)
Feed:gain1
Avg gain/day, g12
Avg feed/day, g1
Avg water intake, s'
Gain: feed ratio2
Item
Pigs were weaned at 28 days and immediately placed on
test for 10 days. Feed and water were available free
choice. Source: Maenz et al.. 1993
I Effect ofwater significant, P<0.05
2
Effect ofenvironment significant, P <0.05
From the above, and from research conducted
elsewhere, it is clear that pigs can perform very
well, even in the presence of very high levels of
sulphate. Interestingly, in every case, scouring was
clearly related to water quality, confirming clinical
observations. What may be most significant to the
industry is that the presence ofscouring should not
be interpreted as causing impaired growth and
productivity. Therefore, pork producers,
veterinarians and nutritionists are cautioned to
separate the effect ofdrinking water quality on
diarrhea from that on animal performance and
determine if indeed, performance is compromised.
This is critical as it has a major impact on how one
responds to a water quality problem. It appears to
run counter to popular thought, but the results ofso
many experiments cannot be ignored.
If the dietary salt is altered inappropriately and a
chloride deficiency results, depressed appetite will
occur. Ifsevere, it could cause a greater production
loss than the water! Interestingly, the beneficial
effects ofsalt removal may be related to a marginal
chloride deficiency which reduces feed intake and
thus is "seen" to reduce diarrhea!
Lowering Nutrient Density in the Diet
Lowering diet nutrient density has proven suc-
cessful in the case ofthe weanling pig, where the
stress ofweaning combined with water proves to be
too much. Adding bulky ingredients, such as beet
pulp or even oats or barley appears to reduce the
visible signs ofscouring, but also greatly reduces
the growth potential of the pig. As with the case of
salt removal, the cure may be worse than the dis-
ease, so such dietary changes must be carried out
with caution.
249

268. Improved Animal Management
A more desirable approach would be to lessen all
stresses on the pig, by improving the overall
environment for the pig (drafts, humidity, crowding,
disease, etc). This enables the pig to withstand the
effects of the water with less impact on its health
and productivity. Jmproving housing, for example,
is generally easier than altering the make-up ofthe
water, and would, in most cases, improve
productivity.
Water Delivery
It is entirely possible that many of the problems
associated with water quality are related to its
delivery. Poor quality water often plugs screens in
drinkers, leaves scale in pipes and generally disrupts
the flow of water from the well to the animals.
Poor delivery systems which actually restrict the
availability ofwater to the animals is a serious
problem on many farms.
Water Treatment
Ifthe problem is excess sulphates, treatment may
not be an option due to cost. Reverse osmosis will
remove sulphates, but both the capital and operating
costs for a livestock unit are very high and the cost
relative to benefit must be carefully balanced.
Chlorination is performed to provide disinfection
and remove deleterious bacteria and other disease-
causing microorganisms. It must be recognized that
protozoa and enteroviruses are much more resistant
to chlorination than arc bacteria; it is not altogether
clear ifchlorination is unsatisfactory in this regard,
but there is definitely cause for concern.
The effectiveness ofdisinfection and the quantity
ofchlorine required in the water will depend on the
quantity ofnitrites, iron, hydrogen sulphide,
ammonia and organic matter content, as well as pH
and temperature. For example, the higher the pH,
the more chlorine must be added to achieve the
same degree ofdisinfection. The presence of
organic matter in the water converts the free
chlorine to chloramines which have less disinfecting
action. The length ofcontact will also influence the
demand for added chlorine.
Water softeners of many types are available. The
most common is the ion-exchange unit, which
replaces calcium and magnesium with sodium. This
reduces the hardness of the water, but clearly has no
effect on overall mineral load. Because of sodium's
role in the process, it is important to recognize that
water softened in this manner will have elevated
levels ofsodium.
lncreasin� nipple flow rates docs little to increase water intake in pigs but greatly increases water wastage.
250

269. Additional Reading and References
Brooks, P.H. and J.L. Carpenter. 1993. The water
requirement ofgrowing-finishing pigs - theoretical
and practical considerations. In (D.J.A. Cole, W
Haresign and P.C. Garnsworthy, Eds.) Recent
Developments in Pig Nutrition 2. Butterworths,
London, pp. 179-200
Fraser, D., J.F. Patience, P.A. Phillips and J.M.
Mcleese. 1993. Water for piglets and lactating
sows: quantity. quality and quandaries. In (DJ.A.
Cole, W. Haresign and P.C. Garnsworthy, Eds.)
Recent Developments in Pig Nutrition 2.
Butterworths, London, pp. 201-224.
Maenz, D.D., J.F. Patience and M.S. Wolynetz.
1993. Effect of water sweetener on the perform-
ance ofnewly weaned pigs offered medicated and
unmedicated feed. Can. J. Anim. Sci. 73:669-672.
Mcleese, J.M., M.L. Tremblay, J.F. Patience and
G.I. Christison. 1992. Water intake patterns in the
weanling pig: effect ofwater quality, antibiotics
and probiotics. Anim. Prod. 54:135-142.
N.R.C. 1974. Nutrients and toxic substances in
water for livestock and poultry. Nat'l Acad. Sci-
ence, Washington, DC. 93 pp.
Patience, J.F., J. Mcleese and M.L. Tremblay.
1989. Water quality - implications in pork produc-
tion, Proc. Western Nutr. Conf., pp. 113-138.
Patience, J.F. 1990. Water requirements ofpigs:
principles and applications. Proc. Minn. Swine
Conf. for Veterinarians, Univ. of Minnesota, St.
Pauls, MN, September 16-18, pp. 380-390.
Patience, J.F. 1990. Assessing water quality:
separating fact from myth. Proc. Minn. Swine
Conf. for Veterinarians, Univ. of Minnesota, St.
Pauls, MN, September 16-18, pp. 31-37.
251

270. 252

271. Appendix I. Typical Nutrient Composition of Selected Feed Ingredients
Alfalfa Meal Barley- Barley- Beet Pulp Blood Meal Bone Meal
Grain Hulless Spray Dried
Energy, kcal/kg
-Digestible 1850 3100 3250 3000 3050
-Metabolizable 1675 2960 3100 2850 2810
Proximate analysis, %
-Crude protein 17.0 10.6 13.7 9.9 84.0 28.0
-Crude fibre 25.6 5.1 3.6 15.3 0.8
-Acid detergent fibre 29.2 7.1 1.2 17.7
-NDF 39.6 17.8
-Ash 9.5 2.4 4.4
-Ether extract 2.8 1.8 1.0
Total amino acids,%
-Lysine 0.76 0.39 0.54 0.60 7.60 1.00
-Threonine 0.72 0.36 0.47 0.40 3.84 0.68
-Methionine 0.25 0.17 0.24 0.01 0.98 0.20
-T.S.A.A. 0.47 0.40 0.47 0.02 1.88 0.43
-Tryptophan 0.36 0.14 0.16 0.10 1.15
-Isoleucine 0.77 0.42 0.45 0.30 0.95 0.54
-Leucine 1.30 0.80 0.95 0.60 12.34 1.21
-Valine 0.93 0.58 0.62 0.40 7.66 1.03
-Phenylalanine 0.90 0.60 0.76 0.30 6.20 0.80
-Arginine 0.74 0.50 0.64 0.30 5.20 1.92
-Histidine 0.34 0.24 0.30 0.20 5.87 0.31
Apparent Ileal digestible amino acids, %
-Lysine 0.36 0.27 6.38 0.77
-Threonine 0.34 0.23 3.11 0.51
-Methionine 0.16 0.13 0.76 0.16
-Cystine 0.05 0.17 0.67 0.09
-Tryptophan 0.19 O.IO 0.92
-Isoleucine 0.42 0.31 0.63 0.41
-Valine 0.48 0.41 6.51 0.93
Macrominerals, %
-Calcium 1.33 0.07 0.24 0.70 .40 30.00
-Phosphorus 0.23 0.35 0.37 0.08 .30 12.50
-Avail. phosphorus 0 0.11
-Magnesium 0.30 0.11 0.21 0.25 .15 0.30
-Potassium 2.27 0.55 1.00 .15 0.10
-Sodium 0.09 0.03 0.19 0.40 5.00
-Chloride 0.46 0.13 0.25 0.25
Microminerals, ppm
-lron 330 90 275 45
-Copper 10 7 9 13 IO
-Zinc 21 24 I 12
-Mangancse 37 20 44 35 5
-Selenium 0.6 0.2 0.04
253

272. Buckwheat Canola Meal Canola Seed Com- Com Com Gluten
Grain Distillers Grain Meal
Energy, kcal/kg
-Digcstiblc 3010 3100 4750 3550 3450 4150
-Mctaboliz-
able 2810 2900 4475 3360 3260 3840
Proximate analysis, %
-Crude protein 11.2 37.7 20.7 8.5 27.6 60.0
-Crude fibre 13.3 11.8 7.0 2.2 12.0 3.1
-Acid detergent fibre 20.0 17.2 3.4
-NDF 12.0
-Ash 2.1 4.8 1.4 2.2 2.8
-Ether extract 2.5 3.5 3.6 9.0 2.4
Total amino acids, %
-Lysine 0.64 2.16 1.20 0.26 0.79 1.03
-Threonine 0.42 1.65 1.01 0.31 0.91 2.05
-Methionine 0.21 0.75 0.40 0.19 0.35 1.60
-T.S.A.A. 0.40 1.79 0.85 0.37 0.80 2.80
-Tryptophan 0.18 0.46 0.27 0.06 0.17 0.35
-Isolcucine 0.39 1.55 0.89 0.32 0.98 2.40
-Leucine 0.63 2.64 1.65 1.04 2.50 10.04
-Valine 0.58 1.99 1.11 0.46 1.30 3.00
-Phenylala nine 0.49 1.49 0.90 0.40 1.45 3.80
-Arginine 0.95 2.26 1.43 0.45 0.95 1.89
-Histidine 0.28 1.34 0.62 0.21 0.60 1.39
Apparent IleaJ digestible amino acids, %
-Lysine 1.60 .17
-Threoninc 1.12 .21
-Mcthionine .59 .16
-Cystine .78 .14
-Tryptophan .29 .04
-Isoleucine 1.12 .25
-Valine 1.55 .36
Macrominerals, %
-Calcium 0.08 0.63 0.39 0.02 0.12 0.06
-Phosphorus 0.32 1.01 0.64 0.25 0.65 0.38
-Avail. phosphorus 0.03
-Magnesium 0.10 0.51 0.38 0.11 0.15 0.07
-Potassium 0.45 1.22 0.73 0.30 0.43 0.24
-Sodium 0.05 0.01 0.40 0.07
-Chloride 0.05 0.04 0.18 0.06
Micromincr-als, ppm
-lron 40 142 95 20 200 230
-Copper 9 6 4 3 50 15
-Zinc 9 69 37 15 55 30
-Mangancse 34 49 22 4 23 8
-Sclenium I. I 0.6 0.05 0.35 0.8
254

273. Fababeans Feather Meal Fish Meal- Fish Meal- Fish Meal- Flaxseed Meal
Herring' Menhaden' Whitc1
Energy, kcal/kg
-Digestible 3150 2250 3725 3700 3550 4550
-Metabolizable 2960 2070 2625 2930 2385 4250
Proximate analysis,%
-Crude protein 26.7 85.0 71.0 61.2 63.8 25.3
-Crude fibre 7.8 1.4 0.8 0.9 0.5 9.5
-Acid detergent fibre 10.0
-NDF
-Ash 6.4 3.7 10.7 19.5 22.7
-Ether extract 1.2 2.5 9.4 9.9 5.4
Total amino acids, %
-Lysine 1.62 1.67 5.82 4.82 4.34 1.20
-Threonine 0.90 3.63 3.09 2.49 2.71 1.10
-Methionine 0.19 0.47 2.19 1.80 1.76 0.44
-TS.A.A. 0.45 4.13 2.91 2.42 2.41 0.80
-Tryptophan 0.26 0.49 0.77 0.69 0.67 0.40
-Isoleucine 0.98 3.79 3.12 2.77 2.81 1.20
-Leucine l.83 6.20 5.41 4.94 4.57 1.80
-Valine l.08 5.85 4.83 3.27 3.48 1.40
-Phenylala nine l.04 3.60 2.81 2.42 2.75 l.60
-Arginine 2.29 5.90 5.26 3.65 3.97 3.00
-Histidine 0.60 0.47 1.83 1.48 1.62 0.70
Apparent Ileal digestible amino acids, %
-Lysine 1.09 4.95 4.10 3.69
-Threonine 2.54 2.41 1.94 2.11
-Methionine .30 1.80 1.48 1.44
-Cystine 2.64 0.46 0.40 0.42
-Tryptophan 0.29 0.58 0.52 0.50
-Isoleucine 2.99 2.53 2.24 2.28
-Valine 4.50 3.96 2.68 2.85
Macrominerals, %
-Calcium 0.12 0.34 2.75 5.11 6.97 0.20
-Phosphorus 0.49 0.53 1.75 2.92 3.94 0.70
-Avail. phosphorus
-Magnesium 0.13 0.13 0.18 0.14 0.20 0.40
-Potassium 1.08 0.20 l.22 0.72 I.OJ 0.80
-Sodium 0.08 0.35 0.81 0.45 l.l3 0.05
-Chloride 0.23 0.83 0.55 2.00 0.04
Microminer-als, ppm
-lron 65 76 110 443 120
-Copper 4 7 5 11 s 12
-Zinc 42 72 135 150 80
-Manganese 12 IS 7 35 18
-Seleniurn 0.90 2.0 2.1 1.5 0.4
I
Published Ileal digestibilities for fish meal do not differentiate the source ofthe product. Variation is likely.
255

274. Lentils Meal Meal Meat and Molasses-Beet Oats Grain Oats Naked
Bone Meal
Energy, kcal/kg
-Digestible 3065 2850 2825 2475 2800 3600
-Metabolizable 2865 2585 2570 2350 2650 3420
Proximate analysis, %
-Crude protein 24.6 55.0 50.0 7.1 10.8 13.2
-Crude fibre 3.9 1.3 2.7 0.0 11.0 3.6
-Acid detergent fibre 4.1 0.0 15.3
-NDF
-Ash 23.2 31.9 8.9 3.4 2.0
-Ether extract 10.1 8.4 0.0 4.2 8.7
Total amino acids, %
-Lysine 1.63 2.99 2.70 0.40 0.50
-Threonine 0.81 1.85 1.65 0.35 0.40
-Methionine 0.18 0.79 0.70 0.20 0.20
-TS.A.A. 0.51 1.40 1.20 0.40 0.54
-Tryptophan 0.25 0.35 0.30 0.14 0.15
-Isoleucine 0.88 1.85 1.75 0.42 0.50
-Leucine 1.64 3.45 3.20 0.78 1.00
-Valine 1.00 2.60 2.30 0.59 0.75
-Phenylalanine 1.09 1.85 1.75 0.59 0.68
-Arginine 1.79 3.70 3.50 0.80 0.89
-Histidine 0.56 1.10 1.05 0.20 0.27
Apparent Heal digestible amino acids, %
-Lysine 2.48 1.89 0.26
-Threonine 1.55 1.09 0.19
-Methionine 0.67 0.54 0.15
-Cystine 0.38 0.27
-Tryptophan 0.21 0.17 0.08
-Isoleucine 1.52 1.24
-Valine 2.13 1.66
Macrorninerals, %
-Calcium 0.08 8.10 9.50 0.10 0.10 0.12
-Phosphorus 0.33 3.63 4.70 0.02 0.35 0.40
-Avail. phosphorus
-Magnesiurn 0.94 0.30 0.30 0.20 0.15 0.11
-Potassium 0.62 0.65 4.60 0.40 0.45
-Sodium 0.04 1.20 0.80 1.20 0.05 0.05
-Chloride 0.90 0.70 1.20 0.10 0.08
Macrominerals, ppm
-Iron 88 450 500 70 75 75
-Copper 7 10 10 15 5 9
-Zinc 46 80 100 15 30 36
-Manganese 10 10 5 40 44
-Selenium 0.4 0.4 0.3
256

275. Peas Potatoes Poultry By- Rye Grain Screenings Screenings
Dried Product Meal #1 Feed #1 Wheat
Energy, kcal/kg
-Digcstible 3400 3350 3250 3300 3100 3250
-Metabolizable 3175 3160 3020 3085 2930 3075
Proximate analysis, %
-Crude protein 23.4 7.7 60.0 11.5 11.2 12.9
-Crude fibre 5.5 5.1 2.5 2.4 4.9 5.5
-Acid detergent fibre 8.2 5.9 4.4
-NDF 14.7
-Ash 3.3 3.3 17.0 1.6
-Ether extract 1.3 0.2 13.0 1.6
Total amino acids, %
-Lysine l.50 0.40 2.11 0.40 0.39 0.37
-Threonine 0.90 0.24 1.57 0.38 0.38 0.37
-Methionine 0.25 0.08 0.70 0.18 0.19 0.23
-T.S.A.A. 0.50 0.16 1.47 0.38 0.44 0.54
-Tryptophan 0.24 0.14 0.50 0.14 0.14 0.14
-Isoleucine l.IO 0.25 1.56 0.45 0.40 0.50
-Leucine 1.80 0.60 2.82 0.69 0.80 0.85
-Valine l.l5 0.35 1.97 0.55 0.58 0.53
-Phenylalanine 1.04 0.40 1.45 0.59 0.57 0.53
-Arginine 1.40 0.27 2.76 0.52 0.56 0.58
-Histidine 0.72 0.15 0.96 0.27 0.24 0.25
Apparent Deal digestible amino acids, %
-Lysine l.25 0.26
-Threonine 0.62 0.23
-Methionine 0.19 0.13
-Cystine 0.15 0.14
-Tryptophan 0.16
-Isoleucine 0.86 0.29
-Valine 0.82 0.36
Macrominerals, %
-Calcium 0.09 1.20 4.30 0.06 0.07 0.04
-Phosphorus 0.50 0.85 2.30 0.32 0.29 0.32
-Avail. phosphorus 0.15
-Magnesium 0.13 0.13 0.39 0.12 0.11 0.13
-Potassium 1.01 1.70 0.40 0.45 0.64 0.30
-Sodiurn 0.04 1.85 0.82 0.02 0.03 0.02
-Chloride 0.05 l.50 0.54 0.03 0.15 0.05
Microminer-als, ppm
-Iron 60 14 450 75 57 30
-Copper 9 45 14 6 7 6
-Zinc 28 3 120 32 24 36
-Manganese 23 4 II 57 21 29
-Seleniurn 0.4 0.06 0.03 0.2 0.1
257

276. Skim Milk SBM- SBM- Soybean Sugar Sunflower
Powder 44% 47% Seeds, Raw Meal - Dehulled
Energy, kcal/kg
-Digestible 3850 3500 3675 4200 3800 3115
-Mctabolizablc 3565 3190 3350 3875 3610 2920
Proximate analysis, %
-Crude protein 33.4 44.3 47.5 37.2 40.5
-Crude fibre 0.0 6.9 3.9 17.2 14.9
-Acid detergent fibre 8.3 7.4 8.0
-NDF 12.0 9.3
-Ash 8.0 6.4 6.5 4.0 6.8
-Ethcr extract 1.8 0.7 1.4 15.0 5.0
Total amino acids, %
-Lysine 2.70 2.86 3.18 2.25 1.39
-Threonine 1.60 1.70 1.85 0.55 1.35
-Methionine 0.85 0.65 0.64 1.10 0.93
-T.S.A.A. 1.30 1.30 1.44 1.54 1.42
-Tryptophan 0.50 0.58 0.62 0.47 0.46
-Isoleucine 1.75 2.26 2.30 1.95 1.56
-Leucine 3.40 3.55 3.68 2.75 2.32
-Valine 2.25 2.17 2.69 1.85 1.88
-Phenylala nine 1.65 2.17 2.44 2.00 1.78
-Arginine 1.15 3.35 3.49 2.65 3.05
-Histidine 0.95 1.14 1.26 0.90 0.84
Apparent Deal digestible amino acids, %
-Lysine 2.43 2.40 2.70 1.03
-Threonine 1.31 1.29 1.44 0.97
-Methionine 0.73 0.55 0.54 0.81
-Cystine 0.36 0.48 0.62 0.36
-Tryptophan 0.46 0.50 0.35
-lsoleucine 1.49 1.85 1.91 1.22
-Valine 1.91 1.71 2.18 1.41
Macrominerals, %
-Calcium 1.20 0.29 0.29 0.25 0.42
-Phosphorus 1.00 0.61 0.60 0.59 0.90
-Avail. phosphorus
-Magncsium 0.12 0.26 0.30 021 0.70
-Potassium l.55 1.90 2.10 1.70 1.10
-Sodium 0.55 0.04 0.01 0.02 0.20
-Chloridc 0.95 0.03 0.03 0.02 0.20
Microminerals, ppm
-Iron 15 140 125 80 30
-Copper 11 25 20 16 4
-Zinc 40 55 60 26 100
-Mangancse 3 30 40 30 20
-Selenium 0.10 0.10 0.10 0.10 0.10
258

277. Triticale Wheat Grain Wheat Bran Wheat Shorts Whey Powder
HRS
Energy, kcaVkg
-Digestible 3375 3425 2475 3140 3350
-Metabolizable 3150 3210 2310 2905 3150
Proximate analysis, %
-Crude protein 13.6 13.5 15.5 17.5 14.0
-Crude fibre 2.5 2.7 10.5 7.5 0.0
-Acid detergent fibre 3.5 13.1 0.0
-NDF 10.8 35.0
-Ash 1.9 6.2 8.2 9.1
-Ether extract 1.5 1.8 3.6 4.2 0.7
Total amino acids, %
-Lysine 0.40 0.40 0.59 0.70 0.95
-Threonine 0.43 0.40 0.49 0.54 0.77
-Methionine 0.19 0.24 0.19 0.23 0.19
-T.S.A.A. 0.44 0.57 0.49 0.50 0.46
-Tryptophan 0.14 0.16 0.27 0.23 0.21
-Isoleucine 0.53 0.53 0.55 0.60 0.83
-Leucine 0.82 0.89 0.92 l.02 1.23
-Valine 0.63 0.56 0.70 0.78 0.70
-Phenylalanine 0.65 0.56 0.57 0.66 0.40
-Arginine 0.71 0.61 1.04 0.98 0.40
-Histidine 0.35 0.26 0.32 0.40 0.22
Apparent Ileal digestible amino acids, %
-Lysine 0.29 .29 0.32 0.50 0.77
-Threonine 0.28 .28 0.25 0.32 0.63
-Methionine 0.16 .20 0.14 0.18 0.17
-Cystine 0.21 .27 0.21 0.24
-Tryptophan 0.10 .13 0.16 0.18 0.17
-Jsoleucine 0.42 .44 0.42 0.73
-Valine 0.49 .44 0.57 0.61
Macrominerals, %
-Calcium 0.05 0.04 0.12 0.10 0.98
-Phosphorus 0.32 0.34 1.16 0.85 0.79
-Avail. phosphorus
-Magnesium 0.12 0.14 0.53 0.27 0.13
-Potassium 0.47 0.32 1.23 0.90 1.62
-Sodium 0.03 0.02 0.05 0.03 1.57
-Chloride 0.03 0.05 0.05 0.04 1.50
Microminerals, ppm
-lron 30 31 150 85 140
-Copper 9 6 11 12 45
-Zinc 45 38 95 105 5
-Manganese 25 30 110 110 5
-Selenium 0.10 0.60 0.50 0.06
259

278. Canola Oil Lard Poultry Grease Soybean Oil Tallow
Energy, kcal/kg
-Digestible
-Mctabolizable
8800
7300
7850
7550
8625
8200
8800
7275
8200
7900
Disclaimer:Every attempt has been made to provide accurate information on each ingredient. Due to the nature of
these materials. variability among samples will occur.
260

279. Appendix II. Calibrating Proportioner-type Mills
l. Ensure that the dial settings for the mill are
correctly set for the diet being tested. Record the
setting for each dial.
2. Remove the back housing cover from the mill to
expose the proportioning augers and attach the
testing tray. Place collecting containers below the
tray to ensure accurate collection ofeach ingredient
from each auger.
Photo IIl-1.
3. Tum on the mill and collect the ingredients until
a reasonable amount is added to all containers. The
more material that can be collected properly, the
more accurate the test will be.
4. Weight the ingredients in each container and
subtract the weight of the empty container. Be sure
to use a small scale that can accurately weigh
ingredients such as premixes and medications.
5. Complete the calculations. Add up the quantity
ofall ingredients to obtain the total. Divide the
weight ofeach ingredient by the total weight to
determine the proportion ofeach in the mix. If the
proportions do not agree with the desired formula,
reset the mill and repeat the procedure.
6. Once the expected formulation has been
achieved on the mill, collect halfa dozen samples
the next time feed is mixed. Thoroughly mix the
samples into a single sample and submit it to a
laboratory for analysis. Refer to Chapter 5 for a
recommended schedule for feed analysis.
261

280. Useful Conversion Factors
Length Miscellaneous
To convert: Multiply by: To convert: Multiply by:
Centimetres to inches 0.394 Calories to joules 4.184
Inches to centimetres 2.540 Kilocalories to calories 1000
Millimetres to inches 0.039 Megacalories to kilocalories 1000
Inches to millimetres 25.40 Joules to calories 0.239
Feet to metres 0.305 Percent to grams per kilogram 10.00
Metres to feet 3.281 Grams per kilogram to percent 0.100
Metres to inches 39.37 Gallons ofwater to pounds 10.00
Inches to metres 0.254 Megajoules to kilocalories 239
Kilometres to miles 0.621
Miles to kilometres 1.609
Area
To convert:
Square foot to square metre
Square metre to square foot
Acres to hectares
Hectares to acres
Volume
To convert:
Millilitres to fluid ounces
Fluid ounces to millilitres
Litres to quarts
Quarts to litres
Gallons to litres
Litres to gallons
Litres to millilitres
Multiply by:
0.093
10.75
0.405
2.469
Multiply by:
0.033
30.00
0.880
1.137
4.546
0.220
1000
262
Temperature
op oc op oc
212 100.0
106 41.l 55 12.8
104 40.0 50 10.0
102 38.9 45 7.2
100 37.8 40 4.4
98 36.7 35 l.7
96 35.6 30 -1. l
94 34.4 25 -3.9
92 33.3 20 -6.7
90 32.2 15 -9.4
88 31. l 10 -12.2
85 29.4 5 -15.0
80 26.7 0 -17.8
75 23.9 -5 -20.6
70 21. l -10 -23.3
65 18.3 -15 -26.1
60 15.6

281. Common Abreviations
Weights
To convert: Multiply by: Length
Grams to ounces 0.035 Kilometer km
Ounces to grams 28.35 Meter m
Kilograms to pounds 2.205 Centimeter cm
Pounds to kilograms 0.454 Millimeter mm
Micrograms to milligrams 0.001 Mile mi
Milligrams to grams 0.001 Yard yd
Kilograms to tonnes 0.001 Foot ft
Tonnes to kilograms 1000
Tonnes to tons 0.984
Tons to kilograms 1102
Tons to tonnes 1.016
Tons to pounds 2000
Parts/million to grams/tonne 1.000 Volume
Grams/kilogram to grams/tonne 1000 Litre L
Millilitre mL
$/bushel to $/tonne Microlitre mcL
(barley) 45.94 Gallon gal
(wheat) 36.75 Quart qt
(oats) 61.25
(corn) 39.37
$/tonne to $/bushel
(barley) 0.0218
(wheat) 0.0272 Mass
(oats) 0.0163 Kilogram kg
(com) 0.0254 Gram g
Milligram mg
Pound lb
Ounce oz
Hundredweight cwt
Tonne (metric) T
263

282. 264

283. Glossary
Abscess - Collection ofpus formed by breakdown
oftissues.
Absorption - The uptake of nutrients through the
intestinal wall.
Acclimatization - The process ofbecoming accus-
tomed to a new climate or other environmental
conditions.
Acute - Having a short and severe course ofdevel-
opment; opposite of chronic.
Adaptation - The adjustment ofan animal to a new
or changing environmental condition.
ADF (acid detergent fibre) - Fibre extracted with
acidic detergent in a technique used in appraising
the quality offorages.
ADG (average daily gain) - Rate ofbody weight
gain, expressed on a 'per day' basis.
Adipose - Fat.
Ad lib feeding - See ad libitum.
Ad libitum - Self-feeding, or allowing swine to
consume feed to appetite.
Agalactia - Absence ofmilk production by the sow.
Albumin -A water soluble plant (and animal)
protein.
Anemia - A condition in which the blood is defi-
cient in the amount ofneeded hemoglobin or in the
number of red blood cells or in both.
Anion - An ion carrying a negative electric charge.
Chloride is an anion.
Anorexia - Lack of loss of appetite.
Anti-nutritional factors - Factors that work against
the nutritional value ofa feedstuff
Anti-oxidant - A substance that prevents fats from
becoming rancid through oxidation.
APF (animal protein factor) - original name for
vitamin B,r
Apparent digestibility - The amount of a nutrient
absorbed from the gut.
Arginine - An essential amino acid.
Arthritis - Inflammation ofa joint and its adjacent
tissues.
As fed - Refers to the nutrient composition of
feedstuffs; including moisture normally present in
the feed at the time it is fed; differs from dry matter
basis, which defines nutrient concentration after aJl
the water is removed.
Assay - The determination of the chemical compo-
sition ofa feed or ingredient.
Aleurone - The protein portion of the endosperm of Ataxia _ Lack ofmuscle coordination.
a seed.
Alfatoxin - Any carcinogenic mycotoxin produced
by molds in stored agricultural crops.
Alkyl resorcinol - A colorless crystalline com-
pound used in making dyes and pharmaceutical.
Amino acids - The building blocks ofproteins;
hundreds are known, but only about 20 are nor-
mally found in proteins.
Amylase - An enzyme that breaks down starches.
Anabolic - The process by which food is changed
into living tissue. Building tissue; opposite of
catabolic.
ATP - Adenosine triphosphate: a source ofenergy
for the cell.
Atrophic rhinitis - Inflammation ofthe mucous
membranes and turbinate bones ofthe nose, often
resulting in distortion in shape or size.
Atrophy - Wasting away of cell or tissue.
Availability - That proportion ofa nutrient that is
available to the animal.
Available amino acids - The proportion of the total
dietary amino acids that can be absorbed from the
gut ofthe pig, and thus are actually used for growth
and production.
265

284. Bacterin -A suspension ofkilled bacteria (vaccine)
used to increase disease resistance.
Bacteria - Single celled living organism that
multiplies by simple division; some arc beneficial
and others cause disease.
Barrow - A young castrated male pig.
Basal (energy) feeds - A group of grain and grain
by-products containing not more than 16% CP and
18% CF.
Basal metabolism (BM) - The chemical changes
that occur in the pig in the fasting and resting state,
when it usesjust enough energy to maintain basic
metabolic activity.
Beta carotene - A source ofvitamin A found in
some plant and plant products.
Beta-glucan - A polysaccharide that interferes with
digestion.
Bile salts - Compounds released from the gall
bladder into the intestine which help emulsify and
digest fats.
Bioassay - Using animals to evaluate feed quality.
Biopsy - The colJection and analysis oftissue
collected from alive animal.
Biotin -A vitamin found in high levels in liver, egg
yolk and yeast.
Boar - Uncastrated male pig.
Bomb calorimeter - An apparatus for measuring
the gross energy content of feed.
Bone meal (steamed) - Ground animal bones that
are steamed under pressure. It can be used as a
source of calcium and phosphorus.
Bran - The seed coat ofcereal grains.
Brewer's grains - A by-product of the brewing
industry.
Bushel - Eight-gallon measure.
Caecum (cecum) -A section of the large intestine
in which bacterial action breaks down some fibre
that escaped digestion i the small intestine.
Calciferol - Commonly known as vitamin D2"
Calorie (cal) - A unit ofenergy measurement
defined as the amount of heat required to raise the
temperature of one gram ofwater from 14.5 to
15.5°C. Equivalent to 4.184 joules.
Calorimetry- Measurement of the amount ofheat
produced during normal metabolism.
Capillary - Small blood vessel delivering arterial
blood to the tissues and venous blood from the
tissues. Walls ofthe capillaries are in close contact
with individual cells ofthe tissues.
Carbohydrates - A class ofcompounds in the feed,
including starches, sugar, cellulose, and gums.
Casein - The major protein ofmilk.
Catabolism - A breakdown oftissues; opposite of
anabolism.
Catalyst - A substance that increases the rate ofa
chemical reaction. Enzymes are catalysts. Cata-
lysts are absolutely essential for the normal body
processes.
Cathartic - A compound that acts as a laxative.
Cation - An ion carrying a positive electrical charge
(i.e. sodium, potassium, and calcium).
Cecum, ceca - See caecume.
Cellulose - The carbohydrate constituent ofplant
cell walls that are resistant to normal digestive
processes in the pig.
Chelating agent - A compound that can bind
mineral ions to improve their utilization by the pig.
Cholecalciferol - Vitamin D3
•
Coenzyme - A substance, usually a vitamin or
mineral, which works with an enzyme to help it
catalyze (speed up) metabolic processes.
Colitis - An inflammation of the colon.
Colon - The lower portion of the large intestine.
Colostrum - The first milk, produced by the sow
during the first few days of lactation; rich in fats
and antibodies essential for piglet survival.
Comfort zone - The temperature range in which
pigs will not expend energy to keep warm.
266

285. Complete feed - Provides all the nutrients required
except water. A balanced diet.
Condition - Refers to the amount of flesh (fat) on
the body; the general health ofanimals.
Congenital - Characteristics ofthe fetus acquired
before birth, i.d. during the gestation period.
Connective tissue - Tough fibrous tissue that
supports and connects tissues ofan animal body.
Creatine phosphate - A storage form of energy for
cell metabolism.
Critical temperature - Environmental temperature
below which extra energy is required to maintain
the pig's body temperature, and less energy is thus
available for growth purposes.
Crude fibre (CF) - That portion of feedstuffs
composed ofcellulose, hemicellulose, lignin, and
other complex carbohydrates.
Crude protein (CP) - An estimate of the protein in
a feed. In calculating the protein percentage. the
feed is first chemically analyzed for its nitrogen
content. Since proteins average about 16% (1/6.25)
nitrogen, the amount ofnitrogen in the analysis is
multiplied by 6.25 to give the CP percentage.
Crumbles - Pelleted feed reduced to granular form
with corrugated rollers.
Cyanocobalamine - Vitamin B12
•
Cyst - A sac or bag-like structure, especially one
that contains a liquid or semi-solid material.
Cystine - Amino acid that can replace up to one
half of a pig's requirement for methionine.
Dermatitis - An inflammation ofthe skin.
Dextrose - Glucose.
Dicoumarol - A chemical compound found in
spoiled sweet clover, which acts as an anticoagulant
causing internal hemorrhages when eaten.
Digestibility - A measure ofthe extent to which a
feed is digested and absorbed by the animal.
Digestible energy (DE) - Gross energy minus fecal
energy; generally pertains to feeds.
Digestion - The processes which feed undergoes
within the gastrointestinal tract to prepare it for
absorption.
Diuresis - Increased urination.
DL-methionioe - Synthetic source of methionine.
DNA - Deoxyribonucleic acid; also called the
blueprint of life because it directs cells in the body
to build proteins in certain ways.
Dressing percent - The portion of the carcass
remaining after removal of most internal organs,
feet, and in some cases the head.
Duodenum - The first portion of the small intes-
tine.
Ear notches - Slits or perforations in an ear used
for identification.
Eczema - Skin disease characterized by redness,
itching, loss ofhair, and the formation ofscales.
Edema - Swelling due to accumulation offluid.
EFA (essential fatty acid) -A fatty acid that
cannot be synthesized in the body in sufficient
quantities for the body's needs.
Electrolyte - Any charged article: an ion.
Electrolyte solution - A solution of simple sugars
and minerals often used in the treatment of scours.
Endogenous - Internally produced in the body,
such as hormones.
Endogenous proteins - Sloughed cnterocytcs
together with enzymes.
Endosperm - Part of the seed which provides food
for the developing embryo.
Endotoxins - Toxic substances stored inside bacte-
rial cells.
Enteritis - Inflammation of the intestinal tract.
Enterotoxin - A toxin produced by microorganisms
that disturbs the gastrointestinal tract.
Enzyme - Biological catalysts that increase the rate
ofchemical reactions.
Enzyme activator - A substance which the enzyme
requires in order to be active.
267

286. Epidemiology - The study of relationships of
various factors that interact to cause or prevent
disease or other health related problems.
Ergocalciferol - Vitamin 02
•
Ergosterol - A plant sterol that (upon activation by
ultraviolet rays) becomes vitamin 02
•
Ergot - Undesirable fungi found in rye.
Ergonovine - A toxic alkaloid found in ergot.
Ergotamine - A toxic alkaloid found in ergot.
Ergotoxine - A toxic alkaloid found in ergot.
Erythropoieses - The production of red blood cells.
Occurs in bone marrow.
Esophagus - Structure extending from mouth to
stomach.
Essential amino acid - An amino acid that cannot
be synthesized in the body in sufficient quantities
for the body's needs; therefore required in diet.
Estrogen - A female sex hormone; promotes estrus
and stimulates the development offemale second-
ary sex characteristics.
Estrus - Heat.
Estrous cycle - The recurring sexual cycle.
Ether extract - Substances in feeds which are
soluble in ether. Used in feed analysis to estimate
fat content ofa feed.
Etiology - The study of the causes ofdiseases.
Feed conversion - Amount offeed used per unit of
gain.
Folacin - Compounds derived from folic acid.
Gastric - Referring to the stomach.
Gastrointestinal - Referring to the stomach and
intestines.
GE - Gross energy.
Gluconeogenesis - Formation ofglucose.
Glutelin - A cereal protein.
Glycolysis - Degradation ofsimple sugars.
Goiter - Enlargement ofthe thyroid gland caused
by iodine deficiency.
Gossypol - A toxic yellow pigment found in
cottonseed.
GRAS - "Generally recognized as safe". Used by
the USDA as related to feed or feed ingredients.
Gross energy (GE) - The amount ofheat released
when a substance is completely oxidized (burned).
Gut - The digestive tract.
Heat increment (HI) - Heat ofnutrient metabo-
lism. This heat may be used to keep the body
warm.
Hemagglutinin - An antibody which causes red
blood cells to stick together.
Hemicellulose - A simple cellulose.
Exogenous - Produced or supplied from outside the Hemoglobin - A protein that imparts a red color in
body. red blood cells.
F I
generation - First-generation progeny.
F 2
generation - The second generation resulting
from the mating of F1
individuals.
Fagopyrin - Photosensitizing agent found in
buckwheat.
Fagopyrism - Buckwheat poisoning.
Farrow - To give birth.
Fat soluble vitamins - Vitamins A, O, E and K.
Fatty acid - A part ofa fat molecule.
Hepatic - Referring to the liver.
Histidine - The mechanisms by which animals
maintain a constant internal environment.
Homeostasis - The mechanisms by which animals
maintain a constant internal environment.
Hormone - A substance, secreted by one gland,
which has an effect on other tissues.
HRS Wheat - Hard red spring wheat.
Hulls - Outer covering of seeds.
268

287. Hybrid vigor - Increased stamina or vitality of
crossbred animals.
Hydrocephalus - Accumulation of fluid on brain.
Ileum - The lower portion ofthe small intestine.
Immunoglobulins - Proteins (also known as
antibodies) that produce a state of immunity.
International units (IU) - An arbitrary scale. used
to compare sources ofvitamins.
Intestine - The portion of the gastrointestinal tract
from the stomach to the anus.
intrinsic factor - A substance secreted by the
stomach which allows absorption ofvitamin B1
�.
In utero - Within the uterus.
.n vitro - Outside the animal in an artificial environ-
ment such as a test tube.
in vivo - Within the living body.
Ion - Charged molecule.
Kcal (kilocalorie) - A unit ofenergy equal to 1000
calories.
Keratin - Protein that composes hair, horn, claws,
and feathers.
Kjeldahl -0 A method of determining the quantity
ofcrude protein based on the nitrogen content.
Lactose - A simple sugar found in milk.
Lesion - Change in the structure, color or size ofa
part ofthe body.
Lignin - A complex carbohydrate that is almost
completely indigestible.
Linoleic acid - An essential fatty acid.
Lipase - An enzyme that breaks down fat.
Lipid - Fat.
Lucerne - Alfalfa.
Macro (or major) minerals - Minerals present or
required in large amounts e.g., calcium, phospho-
rus, sodium, potassium, magnesium, and chloride.
Mastitis - An inflammation of the udder.
Megacalorie (Meal) - Unit ofenergy equal to 101
'
joules.
Menadione - Vitamin K.
Metabolic body size - The weight of the animal
raised to the 3/4 power (W01s).
Metabolism - The sum total of the chemical
changes in the body, including building up {anabo-
lism) and breaking down (catabolism).
Metabolizable energy (ME) - Gross energy minus
fecal energy and urinary energy.
Metabolite - Substance produced by metabolism.
Microvilli - Projections from the villi.
Middlings - A by-product of flour milling contain-
ing endosperm, bran, and germ.
Mycotoxicosis - Poisoning due to fungal or bacte-
rial toxin.
Mycotoxins - Toxic substances produced by molds.
Myrosinase - An enzyme found in rapeseed meal
capable ofbreaking down glucosinolates.
National Research Council - See NRC.
NDF (neutral detergent fibre) - Fibre in the plant
cell wall, which is undigested by swine. Developed
to evaluate forages for ruminants.
Necropsy - Autopsy: postmortem examination.
Necrosis - Tissue death.
Neurotransmitter -A substance involved in the
transmission ofsignals by the nervous system.
Niacin - A vitamin.
Nicotinamide - Niacin.
NFE (nitrogen-free extract) - An approximation
ofthe carbohydrate content in feeds.
NPN - Non-protein nitrogen.
NRC - National Research Council. A division of
the National Academy of Sciences promoting
utilization ofscientific and technical information.
Ochratoxin - A mycotoxin, produced by the mold
aspergillus, which attacks the kidneys, reduces pig
performance and may lead to birth defects.
269

288. Odd chain fatty acids - Those fatty acids with
uneven chain lengths e.g. containing 7, 9 or I l
carbon atoms.
Osteogenesis - Formation of bone.
Osteomalacia - Softening of the bones.
Osteoporosis - Reduction in bone mass.
Pantothenic acid - Vitamin B5•
Parakeratosis - Skin disease.
Parasite - An organism that lives at the expense of
living animals.
Pepsin - A stomach enzyme which breaks up
proteins.
Pepsinogen - Precursor to pepsin;. Secreted by the
stomach.
pH - Measure ofthe acidity or alkalinity ofa fluid.
pH= 7 is neutral.
Phytin - A naturally occurring compound in many
cereal grains containing phosphorus oflow avail-
ability to the pig.
Pneumonia - Inflammation of the lung.
ppm - Parts per million.
Premix - Mixture ofvitamins, trace minerals, and
sometimes macrominerals.
Prolapse - Displacement of tissue from its normal
position, most often the rectum or the uterus.
Proteolytic - Protein degrading.
Pyrodoxine - Vitamin B6
.
Renal - Pertaining to the kidney.
Retinol - Vitamin A.
Riboflavin - Vitamin B2
•
Ridgling - Any male whose testicles fail to
descend; cryptorchid.
Screenings - Residual from the cleaning ofgrains.
Serotonin -A hormone and neurotransmitter.
Starch - A white, tasteless, odorless complex
carbohydrate found in large quantities in potatoes,
rice and wheat.
Tetany - A condition where muscles become rigid
and have spasms.
Thiamine - Vitamin 81
•
Tocopherols - One of the compounds that make up
Vitamin E.
Tocotrienols - One of the compounds that make up
Vitamin E.
Total sulfur amino acids (TSAA) - Methionine
plus cystine.
Tricothecene - A group of mycotoxins, including
vomitoxin (deoxynivalenol), HT-2 toxin, T2 toxin
and diacetoxyscirpenol, produced by thefusarium
molds. They are very toxic compounds, causing
vomiting, depressed growth and suppression ofthe
immune system. The pig is especially sensitive.
Ulcer - Erosion or disintegration oftissues; often
refers to stomach.
USDA - United States Department of Agriculture.
USP - United States Phannacopeia.
VFA - Volatile fatty acids.
Villi - Finger-like projections on the surface ofthe
gut.
Vitamin A - Retinol.
Vitamin B1
- Thiamine.
Vitamin B2
- Riboflavin.
Vitamin B5
- Pantothenic acid.
Vitamin B6
- Pyridoxine.
Vitamin B12
- Cyanocobalamine.
Vitamin C - Ascorbic acid.
Vitamin D2
- Ergo-calciferol.
Vitamin 03
- Cholecalciferol.
Vitamin E - Tocopherol plus tocotrienol.
Vitamin K - Menadione.
Volatile fatty acids - The short chain fatty acids
such as those produced in the rumen of cattle and
the cecume and colon ofswine.
Zearalerone - Also called F2 toxin, is a mycotoxin
produced by thefusarium molds.
270

289. Index
A
absorption 5, 7, 9, 12, 27
ADF 19
Aflatoxin 238
aflatoxin 236, 238, 239
albwnen 25, I 00
alfalfa 18, 28. 42. 45 63, 232, 233,
allergic reaction 5
ammonia 13, 27, 252
amylase 7, IO
anemia 8
animal by-products 235
antioxidant 236
amino acid 22, 28, 147, 159
synthetic 115
appetite 9, 22, 34, 40, 46, 47, 48
arginine 15. 24, 26, 31, 148, 149, 160, 161, 176
available phosphorus 33, 34. 200
B
bacteria 6, 12, 27, 45, 67, 113. 167, 184. 231. 235
barley 18, 65, 126, 130. 132, 183. 197. 218,
232, 235, 253
high moisture 67
hulless 69
barn 18, 119, 129, 141, 157, 200, 213
beet pulp 71, 152, 251, 255
bile 9, 10
bile salts 10
biotin 15, 45, 46
bleeding ulcer 8, 38
blood meal 181, 182
bomb calorimeter 17
bone meal 33, 54, 55, 59. 60, 235
buckwheat 71, 72, 85
bushel weight 2 l. 66, 77. 79. l 02. J 23, 225
c
calciferol 43, 44
calcium 15, 32, 55, 59, 61, 64. 112. 124, 134, 163,
231,234,248,253
calorie 19. l 07
canola meal 24, 28, 33, 45, 52, 73, 83, 126, 130, 197
canola oil 170
canola screenings 85
eanola seed 74, 75, 110, 11 l
carbohydrate 5, I 0. 12, 16, 19, 20, 32, 39. 45, 47
carcass grading 70, 189, 193, 204
carmelization 29
carotene 42, 43, 68
carotenoid 42
cecum 12, 27
cellulose 19
chemical analysis 1, 33, 68, 113, 245
chewing 7
chloride 15, 34, 35, 248, 249
choline 41, 46, 150, 163, 199, 232
chymotrypsin I 0, 86, 91
cobalt 15, 34, 36, 37, 45
colon 12
colostrwn 82, 111, 167, 168, 169, 172
comfort zone 143
computer formulation 123, 124
computers 3
conception 133, 154, 155, 162, 170
condition scoring 143, 144, 146
copper 15. 32, 36, 113, 150, 163 184, 200. 228, 232
com 15, 18, 32, 52, 76. 202. 239
com gluten feed 78
com gluten meal 45, 78
com oil I 08, 170
creep feed 90, 169, 170, 171, 172, 179, 180, 183
criticaltemperature 143, 147, 163, 184
crumbles 171. 180, 221
cyanogenetic glycosides 82
cystine 22, 29, 31, 36, 80, 85, I 00, 164, 198
D
deflourinated phosphate 112
dermatitis 46
diarrhea 34, 39, 41, 47
dicalcium phosphate 112, 232
dicoumarol 47
dietary requirement 46
digestible nutrients 12
digestive enzymes 7, 8, 9, I 0, 12
digestive tract 5, 6, 113. I 14
DL-methionine 115, 182
dressing percentage 58, 70, 189
dried bakery product 80
duodenum 12
durum 100
271

290. s
saliva 7
salivary enzymes 7
salt 34, 35, 36, 38, 41, 46, 59, 80
sample diet 153, 182, 20 I, 202
saponins 63. 64, 94
scours 39, 40, 170
selenium 31, 39, 40, 44, 64, 82, I 09, 168
self-feed 142, 143, 177
small intestine 8, 11
soapstocks I 08
sodium 34, 35, 36, 40, 47. 248, 249, 251, 252
sorghum 47. 72, 232, 233, 234
soybean meal 19, 20, 24, 26, 45, 51, 73. 83, 96, 178
soybeans 27, 45, 93, 109.
starch 5. 7. IO. 19, 65. 76. 80, 82, 90, 222
stomach 5, I 0, 12, 22, 27, 35, 45, I 03, 116
stress 8, 12. 244, 250, 251. 252
sucrose 10
sulphur 22, 36, 54, 69, 74, 83, 85, 86
sunflower meal 97. 98. 238
sunflower seed 97, 98. 99, 233
T
tallow 59, 107, 108, 180
tannins 63, 72, 81, 86, I 00, 231, 233. 234
taste 7
thiamine 42, 48
threonine 29. 30, 31, 85, 100, 105, 106, 115.
153. 160, 161 182. 198
thyroxine 38
total sulpher amino acids
toxin 231, 236. 237. 238, 240
tricothccenes 231. 238
triglyceride 154. 166
triticale I 00. IO I
trypsin 100
tryptophan 23. 25. 29. 30, 47, 55, 115, 153. 182
u
ulcers 8, 9, 138, 221
v
valine 15, 24, 28, 31, 148, 149, 160, 161, 176
villi 9, 10. 11, 12
vitamins 15. 40, 150. 161, 228
vitamin A 15, 40, 42, 60, 150, 151, 162, 199, 249
vitamins B 15, 36, 45. 47. 48, 150, 162. 163, 199
vitamin C 199
vitamin D 15, 34, 42, 43, 44, 47, 199
vitamin E 15, 39, 40. 44, 45. 199. 213
vitamin K 42. 47, 199
fat soluble vitamins 41
stability 41
supplement 41
water soluble vitamins 41
volatile fatty acid 12
vomitoxin 77, 104, 236, 238, 239, 240
vulva biting 139
w
water 168, l 71, I 77, 241
delivery 244. 250
quality 245
wheat 84, IOI. 201
bran 65. 71, 98. 104. 152
middlings 104
red dog 104
screenings 84
shorts 104. 105
whey 170. 171. 261
z
zearalenone 231, 236. 237. 238. 240
zein 26. 76
274

291. Authors
John F. Patience, Ph.D.
Dr. Patience received his B.Sc.(Agr.), majoring in Animal Science and
M.Sc. in Animal Science from the University ofGuelph. Following
employment in extension and in the feed industry, Dr. Patience re-
turned to school, earning a Ph.D. in Nutritional Biochemistry from
Cornell University in 1985. He was employed as a Visiting Fellow at
the Animal Research Centre in Ottawa and, in 1987,joined the Univer-
sity of Saskatchewan as a Research Scientist and Director ofthe Prairie
Swine Centre. When Prairie Swine Centre was incorporated in 1991,
Dr. Patience was appointed its first President and ChiefExecutive
Officer. His research interests include nutrition ofthe growing-
finishing pig, dietary influences on acid-base balance and water quality
and requirements.
I I
Phil A. Thacker, Ph.D.
Dr. Thacker is currently a Professor in the Department ofAnimal and
Poultry Science at the University of Saskatchewan where he teaches
both graduate and undergraduate courses and conducts research in
swine reproduction, enzyme utilization in swine diets and alternative
feed ingredients. Dr. Thacker received his B.S.A. and M.Sc. from the
University ofBritish Columbia and a Ph.D. in Animal Nutrition from
the University ofAlberta. Prior tojoining the University of Saskatch-
ewan faculty, he was employed as an extension swine specialist with
Alberta Agriculture.
C.F.M. (Kees) de Lange, Ph.D.
Dr. de Lange received his early education in the Netherlands where he
was born. He earned his B.Sc. and M.Sc. in Animal Nutrition from
Wageningen Agricultural University. ln 1985, be enrolled at the
University of Alberta where he earned a Ph.D. in Animal Nutrition.
Following graduation, he was Research and Technical Service Man-
ager for swine nutrition at Ralston Purina Canada. During this period,
Dr. de Lange developed his keen interest in the development and
application ofgrowth models in swine production. In 1992, he joined
the staffof the Prairie Swine Centre Inc. in Saskatoon. In 1994, he
was appointed Assistant Professor ofSwine Nutrition at the University
ofGuelph, where he continues his interest in growth models and
conducts research in amino acid metabolism.