A nutrient is a dietary essential for living beings. All of the nutrients known fall in one of
the following categories: proteins, carbohydrates, lipids, minerals, vitamins and water:
Protein is composed of amino acids. There are several hundred known amino acids in
plants. However, only 20 amino acids make up animal proteins. Of these, ten can be
formed in the tissues, whereas the others must be provided in the diet. The essential
amino acids must be provided in the diet (in ruminants can be synthesized by the
microbes in the gut).
Essential Amino Acids are; Argennine, Histamine, Isoleuecine, Leucine, lysine,
Methionine, Phenylalanine, Threoninel, Tryptophan and Valine.
Nonessential Amino Acids are: Alanine, Aspartic acid, Cysteine, Cystine, Glutamic acid,
Glycine, Prolin, Serine, Tyrosine.
In general, proteins contrain about 16 percent nitrogen. The protein content of feeds can
be measured by determining the nitrogen content and multiplying by the factor of 6.25.
Therefore crude protein can be defined as nitrogen (N) × 6.25 (16 g of N come from 100g
of protein. Therefore 1g of N is associated with 100/16 =6.25g of protein).
Carbohydrates are the products of photosynthesis in plant. The basic units of
carbohydrate are sugars such as glucose. More complex carbohydrates, such as cellulose,
hemicelluloses and starch, are composed of large numbers of simple sugars joined
together. Starch is a readily digested carbohydrate stored in plant seeds and cereal grains
are high in starch. Cellulose and hemicelluloses are major components of plant fiber like
Those substances in plants and animals that are soluble in organic solvents like ether are
called lipids. The principal lipids are fats and oils. Fats are usually of animal origin,
whereas oils are from plants and marine animals. Fats have higher proportion of saturated
fatty acids than oils. Saturated fatty acids are usually solid at room temperature, with the
exception of coconut oil, because it contains a high proportion of short-chain fatty acids.
Various minerals are dietary essential for animals. Those required in relatively large
quantities are termed microelements/macro minerals. Those needed in small quantities
are called trace/micro elements. Macro minerals normally function as components of the
tissues (e.g. bone), whereas trace minerals function as activators or cofactors of enzymes.
Macro minerals include: Calcium, Phosphorus, Sodium, Potassium, Chlorine Magnesium
Trace minerals include: Manganese, Zinc, Iron, Copper, Molybdenum, Selenium, Iodine,
Cobalt and Chromium.
A vitamin is an organic nutrient (other than carbohydrates, lipids, and protein) needed in
extremely small quantities; is essential for normal metabolism and normally is dietary
essential. However, vitamin D can be synthesized by animals exposed to sunlight; niacin
can be synthesized in some animals from the amino acid tryptophan; vitamin C (ascorbic
acid) can be synthesized by most animals except primates. Fat soluble vitamins are: A, D,
E and K. Fat soluble are: thiamine (B1), Riboflavin (B2), Pyridoxine (B6),
Cyanocobalamin (B12), Nicotinic acid (niacin); Folic acid (folic in), Pentothenic acid,
biotin, choline, and vitamin C.
Functions of Nutrients
Structural Role: Some nutrients function in making up the structure of the animal body,
which include protein, Ca, P, and to a lesser extent, lipids and carbohydrates.
Source of Energy
Energy is used for locomotion and thermoregulation, maintenance and growth of living
tissues, production and reproduction.
Energy is expressed in calories. A calorie is defined as the amount of heat required to
raise the temperature of one gram of water by one degree centigrade. A kilocalorie (kcal)
is equal to 1000 calories, and a mega calorie (mcal) is equal to 1,000,000 calories. One
caloric is equal to 4.184 joules.
The main nutrients that provide energy to animals are carbohydrates and lipids. Cellular
metabolism is basically the reverse of photosynthesis
C6H12 O6 + 6O2+ADP cellular/ enzymes ATP + heat + 6co2 + 6h2O
Sodium, Potassium and chlorine function in fluid balance of dissolved substances.
Vitamins and most minerals function as cofactors or activators of enzymes, which
catalyze thousands of chemical reaction in tissues for example, vitamin A functions in
enzymatic reaction in vision, thus its deficiency causes blindness.
The purpose of providing feedstuffs and formulating diets is to provide animals with the
nutrients they require. At least 80 percent of the total feed intake of most animals consists
of sources of calories. Animals eat to satisfy their energy requirements.
The protein requirement varies with species, stage of growth and type of production, but
generally is less than 20% of the diet. For mature beef cows, the protein requirement is
about 6%: and for a mature ewe, 9%.
Minerals requirement can be met in approximately 3 to 4% of the diet. Salt is added
@0.25 to 0.5%. Calcium and P requirements for most species are in the 0.5 to 1% range,
and the requirements for trace elements are met with less than 0.5% of the total diet.
Thus a “typical” diet for livestock will contain 10 to 20 percent protein, 80to 90% energy
yielding nutrients; 3 to 4% minerals, and a trace of vitamins.
Classification of Feedstuffs
Feedstuffs can be classified as either concentrates or roughages. Concentrates have a low
fiber and a high either energy or protein or both. Protein supplements generally contain
more then 20% CP.
1. Concentrates Feeds high in NFE and TDN and low in CF (<18%). (energy
sources) (Carbonaceous feeds): corn, sorghum, barley, rice, wheat, etc.
Grain milling by-products: wheat bran, rice bran and polishing, corn gluten meal,
Roots and tubers: casscava, potatoes, turnips, sugar beet, etc
Food processing by-products: molasses, citrus pulp, bakery waste, distillers and
brewers by-products, etc.
2. Concentrates (protein supplements) (nitrogenous feeds).
Oilseed meals/cakes: cotton seed, rapeseed, sunflower, canola, etc.
Grain legumes: beans, peas, pulses, etc
Animal Proteins: fish meal, meat meal, feather meal, whey, blood meal, tank age,
Nitrogen Sources for ruminants: NPN: Urea, DAP, Poultry waste, biuret, etc.
Bypass protein: corn gluten meal, etc.
3. Roughages: Pasture, Grasses, Legumes, Green chop, silage, dry forage, straws,
stovers, etc. (main feeds of ruminants and herbivorous non-ruminants).
Agricultural by-products: corn cobs, hulls, bagasse, etc.
4. Feed Additives: Mineral supplements: salt, limestone, DCP, Vitamin
supplements; synthetic amino acids; Drugs: antibiotics, ionophores. Preservativer:
antioxidants, mold inhibitors; buffers, enzymes; hormones; flavors; probiotics;
pellet binders, etc.
Techniques used in feed evaluation.
For the efficient utilization of feedstuffs in animal feeding, knowledge of their
composition, digestibility or bioavailability, ability to provide energy, presence of toxins
or anti-nutritional factors, palatability, etc is very important. Some common techniques of
feed evaluation are:
Feed Microscopy: it is the evaluation of the feed sample with a microscope for
identifying its components.
Feed Analysis: The standard chemical method of feed analysis is called proximate
analysis. Its components include: dry matter (DM), crude protein (CP), ether extract (EE),
ash, crude fiber (CF) and nitrogen free extract (NFE)
Determination of Specific Nutrients
Amino acids are measured by column chromatography (AA auto-analyzer). Minerals
such as calcium, phosphorus, copper, and zinc can be measured by spectrophotmetric
procedures or by atomic abruption spectrometry. Specific vitamins are measured by
chromatographic procedures, such as high performance liquid chromatography (HPLC).
Near infrared reflectance spectroscopy is also used for feed analysis. Feed samples are
exposed to infrared radiation, and the reflectance of the radiation by the sample is
measured. The instrument is calibrated by mathematically equilibrating reflectance values
with known chemical values for a series of samples of a particular ingredient.
The caloric content of biological materials is determined in a bomb calorimeter. The
sample is burned in a combustion chamber (bomb) inserted in a vessel containing a
known weight of water. As the sample burns, it releases heat which is taken up by the
water. From the weight of the sample, weight of the water, and rise in the temperature of
the water, the calories of heat energy released can be calculated, which is called gross
energy. To calculate digestible, metabolizable and net energy, metabolism trials must be
Digestible energy (DE): cross energy (GE)- fecal energy.
Metaholizable energy (ME): DE-(urinary energy + rumen gas losses)
Net energy (NE) = ME-heat loss
Thus NE is the fraction of GE which is actually utilized for production.
Total digestible nutrients (TDN: This is an older method of estimating digestible energy.
Fats yield about 9 kcal/g, whereas protein and carbohydrates yield about 4 kcal/g.
Determination of Digestibility
Digestibility measures the amount of a nutrient in a feed that is digested and absorbed
and thus available for metabolism. The difference between the amount of nutrient
consumed and excreted in the feces is the amount digested and absorbed.
Example of digestibility calculation
An animal housed in a metabolism crate consumes 20 kg of the test diet, and excretes 10
kg of feces. The CP of feed is 15% and of feces 7%.
Therefore, (1) Protein intake = 20 × 0.15 = 3 kg
(2) Fecal protein = 10 × 0.07 = 0.7 kg
(3) Protein digested = 3 - 0.7 = 2.3 kg
(4) % Protein digested = (2.3/3) × 100 = 76.6%.
By using the marker like chromic oxide, and measuring its concentration in feed and
feces by taking grab sample, digestibility can also be measured.
Grain and their by-products
Cereal Grains: Cereal are the members of the grass family (Gramineae). Grains are
edible seeds; thus cereal grains are the seeds of cultivated grasses. They are the primary
energy source for humans and non-ruminant animals. Approximately 90% of the human
food supply worldwide is derived from following crops, listed in order of importance:
wheat, rice corn, potato, barley, sweet potato, cassava, soybean, oats, sorghum, millet,
rye, peanut, field beans, pea, banana; and coconut.
Almost half of these crops are the eight major cereal grains: wheat, rice, corn barley, oats,
rye, sorghum and millet. Wheat, rice and corn made up about 75% of the total world
grain production. With the exception of Rye grains are very palatable to livestock.
General Structure of Grains:
The seed consists of the plant embryo (germ); the endosperm and the outside protective
layers. The outermost layer is the hull, which is high in fiber and protects the seed from
mechanical damage and invasion by pathogens. Beneath the hull is the aleuronic layer
(bran) which contains fiber and protein. Inside this bran is the endosperm, consisting
mainly of starch. Imbedded in the endosperm is the germ, or seed embryo. The germ is
high in oil, protein, and the other nutrients, which the sprouting seed will use for growth.
The endosperm is primarily a reserve of energy for the developing seed.
General features of a cereal grain
Corn or Maize (Zea Mays): Corn is the world’s most important feed grain. It is adapted
over a wide range of climates and can be rapidly modified by plant breeding to produce
cultivars (verities), which are production in new environments.
Corn can produce more energy per acre than any other cereal grain. Corn is unique
among grains in having male and female flower organs separately on the some plant; the
ear contains the ovary and the tassel produces pollen. This has allowed the development
of high yielding corn verities.
It has the highest digestible energy content for animals. It is very palatable and contains
no intrinsic toxic factors. Thus it can be regarded as the best feed grain. In addition to its
high yield, corn produces large amounts of leavers and stalks. Corn is a high energy grain
because it is high in starch and oil and low in fiber. In the non ruminants, the starch in
corn is of high digestibility. It is primarily digested in the small intestine. Glucose is the
end product of starch digestion in the non ruminants. The absorbed glucose is the primary
energy source for cellular metabolism.
C6H12O6+6O2+ADP cellular metabolism> ATP+6CO2+6H2O+heat. Cellular metabolism is
basically the reverse of photosynthesis.
It is necessary to break down the waxy external shell of the kernal to permit its
degradation in the rumen. Corn oil is high in unsaturated fatty acids (essential fatty
acids), which are exuded in the hair follicle, giving animals a sleek, shiny hair coat. Corn
grain has 8 to 10% CP and about 4% oil, but is an excellent energy source.
The quality of protein refers to its content of essential amino acids (AA). A good quality
protein has an amino acid profile similar to the essential requirements of animals. Corn
grain is recognized as poor quality, being deficient in lysine and tryptophan, and low in
methionnine. For non ruminants corn must be supplemented with a protein supplement to
supply the deficient AAs. A higher faction of the total protein in corn is of the polyamine
fraction than is true for most other grains. Polyamines have a very low lysine and almost
no tryptophan. Polyamine content (% of seed protein) of various cereal grains are:
Wheat-45; barley-40, oats-12, rice-8, corn-50, sorghum-60, millet-60.
Vitamins: Yellow corn is the only cereal grain to have significant vitamin A activity. Its
yellow color carotenoid pigments are the precursors of vit. A. Plants do not have vitamin
A as such, but rather contain vit. A precursor such as B-carotene, which is two molecules
of vit. A joined together. An enzyme in animal tissue can split these two molecules apart
to liberate vit. A. The richest sources of B-carotene are marine animals and fish liver oils.
This is because vit. A accumulates in the liver. Carotene pigments function with
chlorophyll in photosynthesis.
Corn also contains carotenoids called xanthophylls, which are important in poultry
production for providing the yellow coloration of egg yolks and of the skin of broilers.
Alfalfa meal and synthetic xanthophylls are also fed for this purpose.
Corn has a low quantity of available niacin (nicotinamide or nicotinic acid). Niacin can
be synthesized by animals from the AA tryptophan. Corn is low in vit. D and the B-
complex vits. In common with all plants corn is devoid of vitamin B12 activity.
Minerals: As is true for all cereal grains, corn contains very little calcium (Ca) (1.1%). A
Ca. supplement is always needed for grain based diets. Corn is moderately high in
phosphorus (0.3%). However, for non ruminants, much of this is “organic P”, which is
largely unavailable. It is tied up as phytic. Grains contain phytic acid, which binds P.
Each phytic acid molecule can bind six phosphate groups, forming an unobservable
complex. Phytic P is of particularly low availability to young animals. In diets for chiks,
the P in corn and other grains is usually ignored in ration formulation. Phytate is digested
by microbial phytase in the rumen, so organic P is bioavailable to the ruminants.
Deletarious factors in corn
Corn is aften contaminated with myco-toxins, which are toxins elaborated by molds
(fungi) growing in or on feedstuffs. They may be produced while the crop is growing or
during storage. In general, toxigenic fungi grow best under warm, humid and aerobic
conditions. The major mycotoxin of concern with corn is aflatoxin, produced by the mold
Aspergillus flavus. Drought and insect damage promote infection of the developing grain.
Infected corn is not necessarily visibly moldy.
Aflatoxin causes reduced feed intake, poor growth, and diarrhea. Chronic exposure
causes liver damage. Aflatoxin is the most potent carcinogen known. At dietary levels as
low as one ppb, it causes liver cancer in rainbow trout. The maximum level of aflatoxin
permitted in feed ingredients by the Food and Drug Administration (FDA) in the USA is
20 ppb in grains intended for human food use, and for dairy animals. Contaminated corn
may be blended with clean corn for livestock use but not for human use.
Other mycotoxins associated with grains are zearalenone (F-2 toxin), ochratoxin, T-2
toxin, vomitoxin, and citrine. The first signs of mycotoxicosis are poor growth, reduced
performance and poor efficiency.
Stored grains must contain less than 15% mistune, or else molding and/or rotting will
Corn-soybean meal diets are standard for swine and poultry production in the USA and in
much of the rest of the world.
Grain Sorghum and Millet
These are the major food grains in the semiarid tropics, an ecological zone encircling the
globe and including Chins, India, most of Africa, Australia, Argentina, and parts of
Southern US. In the developed world about 96% of these 2 grain are grown for animal
feed, whereas in the developing countries only 8% of these crops are used for livestock.
In the Sahelian zone of Africa, about 90% people use these as food. Sorghum is hardy,
drought resistant crop adapted to environmental conditions too hard for the production of
corn. It requires less water than corn and can survive drought and then resume growth
when moisture becomes available.
Millets are relatively minor crops except in localized areas of Asia, Africa and the SSR.
Millet is grown primarily as bird feed. It holds potential as a food crop adapted to
marginal, drought-stricken areas, although it is viewed as poor person’s crop.
Energy: Grain sorghum is quite similar to corn in its composition. Normal sorghum
contains approximately 27% amylase and 73% amylopectin; waxy sorghum contains only
Amylopectin; thus of higher feeding value.
Sorghum is equal to or slightly lower in value than corn as an energy source. It requires
more vigorous processing to achieve optimal digestibility. Because of various tannin
content and coat color, feeding value of various cultivars varies widely. Brown, high
tannin bird resistant vanities give poor animal performance and lower digestibility.
Protein: like corn, sorghum is a fairly poor source of protein, with high prolamine
content. Tannins (Phenolies) in sorghum reduce protein availability. In ruminants, tannins
in bird-resistant sorghum greatly reduce protein availability in the rumen and small
The principal deleterious factors in grain sorghums are condensed tannins, which react
with proteins, and are astringent. During ripening, the tannins are reduced and condensed,
which reduces the astringency. Tannins react with digestion enzymes and reduce nutrient
digestibility. Treatment with sodium or ammonium hydroxide, anhydrous ammonia, or
polyethylene glycol reduces tannin content.
Wheat: Is the world’s most important crop and preferred grain for baking. There are
spring and autumn wheat, and autumn wheat is more productive. Hard wheat is preferred
for bread flyover, because they have high gluten content. Gluten is a protein that forms a
strichy mass of dough, trapping Co2 produced by the yeast, causing bread to rise (leaven),
and hard wheat tend to have protein contents of 11 to 14%. Soft wheat has protein
content of 8 to 11%. These are suitable for cake, cookie, and pastry flour. Hard wheat is
grown in areas with a fairly dry growing season. Soft wheat is produced in humid or
irrigated areas. Wheat is used as a feed when the price is low or when its quality is
inadequate for milling purposes, as when damaged by frost, drought, rain, or disease.
Nutrient Content of Wheat
1. Energy: Wheat is virtually identical to corn in digestible energy content for all
livestock. However, can cause digestive disturbances of ruminants because of
rapid digestion rate of its starch.
2. Protein: Its quantity and quality is superior to corn. Lysine is the most limiting
AA for poultry, followed by threonine and methionine.
Deleterious Factors: It is not normally infected in the field with mycotoxin producing
fungi, so mycotoxins are not of concern unless the grain is improperly stored.
Use of wheat in animal Diets: Wheat can be substituted for corn in poultry diets. Whole
wheat can also be fed to poultry. For ruminants, lactic acidosis is more common with
wheat based diets than with other grains because of the rapid fermentation rate in the
Barley: It ranks fourth among world crops. It is normally grown in cool climates with a
short growing season. Barley is grown primarily for malting and for feed. The spent
grains are used as wet or dried brewer’s grains for feed. There are spring and winter
verities (two or six-row), with fine kernel colors white, black, red, purple, and blue; with
rough or smooth- awn varities: Hull-less verity are also found.
1. Energy: Corn, wheat, triticale, and sorghum are considered as high-energy grains,
whereas barley and oats are lower in energy, particularly for non ruminants. The
lower energy value is due to lower starch content, a higher content of poorly
digested glucans and high fiber content. The viscosity of B-glucans reduces
intestinal flow rate and thus feed intake, and reduce fat absorption. In poultry, the
hydroscopic nature of glucans makes the excreta wet and sticky, causing
management problems. With young chicks, the glucans in barley may cause a
pastyvent condition, causing gut blocking. Hot, dry growing conditions increase
B-glucans levels. Soaking barley in water activates B-glucanases in the seed,
reducing the glucans content.
The glucans can be digested by microbial action in the rumen. Verities having 3.5
to 4.8% glucans was 98 to 99%, indicating virtual complete digestion. Hull-less
barley is equivalent to wheat as a cereal grain for laying hens.
2. Protein: Barley is superior to corn in its protein content and quality. Barley
normally ranges from 11 to 13% crude protein (CP). Lysine is the first limiting
AA (as is true for most grains); and threonine is the second limiting.
Oats (Avena sative):
It is a minor grain, but has the highest protein content and quality of any cereal grain.
However, the energy yield per acre is very low than with other grains. In short-season
areas where corn cannot be produced, oats and barley may be important crops.
Oats had their hey-day when horses were the main source of mechanical process. Oat
grain is an ideal feed for working horses. It is very palatable, but its high fiber content
reduces the likelihood of “overeating” problems such as colic and founder. Oat straw is
softer and more palatable then other cereal straws.
Oats will continue to be produced for specialty purposes. These include the production of
break fast cereals and other food products. Oat bran, containing soluble fiber (B-glucans),
has favorable effects on lowering serum cholesterol. Oats are an ideal grain for horses.
They are useful in creep and starter diets for young animals because of their high
palatability and low energy; they are less likely than other grains to cause disease of
overeating such as enterotoxaemia, acidosis, colic and founder.
1. Energy: Oats have low energy, because of their low starch and high fiber content.
They are unusual in having a low energy but the highest oil content of any grain
(5% or more).
2. Protein content of oats: have the highest quality protein of any cereal grain and
often high protein content as well. They have the lowest prolyamine content of
3. Other nutrients: Have higher mineral content than other grains.
Rice (Oryza sativa):
It is a major food grain for millions of people in the tropics, particularly in Asia. The
unprocessed grain contains about 25 % of its weight as hulls. Rice hulls are high in silica
and are abrasive to both feed mill equipment and the digestive tract. The hulls are almost
totally indigestible. The rice grain is similar to corn in nutritional value. Processing rice
for human consumption produces large quantities of rice bran, which is a very good
feedstuff for livestock as cereal milling by-products.
Wheat Bran: Is quite palatable and able to prevent constipation. A notable characteristic
of bran and other milling by-products is that the P content is very high and the Ca is low.
High phosphorus: low-calcium ratio in the diet can provoke a condition called nutritional
secondary hyper parathroidism. The excessive mobilization of bone Ca results in the
bones becoming demineralozed and fibrotic (”big head” in horses). In the past it was
called “miller’s disease”.
Because of their bulky nature and high fiber content, bran and other mill feeds are not
usually fed to swine and poultry. They are most suitable for ruminants and herbivores
like horses and rabbits. Its low energy content prevents carbohydrate overload condition
such as founder and colic in horses and enterotoxaemia in rabbits.
Brans are good sources of water soluble vitamins, except for niacin. Much of the P of
bran is not available to poultry. Pelleting the bran improves its digestibility.
Rice Bran/Rice Polish
It consists of fibrors outer layer of the grain, some hull, chipped grain and calcium
carbonate, which is added during the milling process. Rice bran is the major feedstuff for
poultry and ruminant herbivores. It is high in oil content (up to 13%) which increases its
energy value to the level of grain itself. However, it also contains factors that promote
rancidity, especially under the warm, humid conditions that favor autooxidation. Rancid
feeds are unpalatable and potentially toxic. Rice bran has a high phytate and lower zinc
content. Rice bran contains variable levels of hulls. Hulls are high in silica, which makes
them very abrasive, and reduces their digestibility. They increase the wear on feed mill
equipment and may cause damage to the gut lining. Heat treatment of rice bran may
improve its utilization by poultry, by inactivating lipoxidases and try-psin inhibitors.
Corn gluten feed and meal: These are produced as by-products of the wet-milling of
corn for starch or syrup production. Meal has approximately twice the protein content
(40%) of the gluten feed (20%). In Pakistan corn gluten with 30% CP is also available.
Classification of Feeds
(From: Principles of AN and Feed Technology by D.V. Reddy)
1. Non-maintenance roughages have below 3% digestible crude protein (DCP) e.g.
straws and stovers
2. Maintenance type roughages have about 3-5% (DCP) e.g. non-legumes: cereal
fodders + grasses and their hay
3. Productive type roughages have more then 5% DCP e.g. legume fodders and their
Technically forages mean hay, straw, silage and pasture while roughages include rice
husk, ground nut (peanut) shells, etc. Products containing more than 18% CF or more
than 35% cell wall in their dry state are classified as forages and roughages.
Hay: Dried tender stemmed leafy plant having <12-14% moisture.
Straw: Byproduct of any cereal or legume crop leftover after harvesting, threshing and
removal of grains or pulses.
Fodder: Aerial plant parts with ears, with husks or heads.
Stover: Aerial plants without ears, without husks or heads
Hull: Outer covering of beans, peas, cotton seed, etc.
Husk: Dry outer covering of grains, grams, etc.
Shells: Hard outer covering of nuts.
Soilage: Pasture when cut and fed green to an animal in its own stall
Calorie (cal): Amount of heat required to raise one gram water temperature from 14.5o
Kilo Calorie (kcal): Heat required to raise temperature of 1 kg of water by 1o
C or = 1000
Mega Calorie (Mcal): Is equal to 1000 kcl or therm. One calorie = 4.18 joules.
BTU: Heat required to raise temperature of 1 lb of water by 1o
F. One kcal = 4BTU.
Metabolic Body Size: Is the weight of the animal in kg raised to the three-fourths power
(Wkg 0.75). This may be termed physiological weight, while body weight is the physical
i.e. gravitational weight.
In ruminants fed roughages about 40-50% of gross energy (GE) intake is lost in feces;
and in case of concentrates 20-30% of GE; is lost. In horses 35-40% of GE; Cattle fed
maize and lucern, at levels ranging from one-half maintenance to twice maintenance may
lose 6.42 to 9.83% of GE as methane.
Generally energy lost as methane is of the order of 7% of GE
The methane production in horses in less than ruminants. Methane contains 13.34 kcal
Urinary energy is of the order of 4 to 5% of GE, in cattle.
Gross energy value of some nutrients/substances (kcal/gram): carbohydrates 4.15; Fats
9.4; protein 5.65 glucose 3.76; sucrose 3.96; starch 4.23, acetic acid 3.49; propionic acid
4.96; butyric acid 5.35; urea 2.53; uric acid2.74; hippuric acid 5.65; methane 13.34.
TDN = DCP + DCF+ DNFE + (DEE*2.25). It is apparent digestible energy.
Nutritive Ratio (NR): It is the ratio of the digestible protein to the sum of the digestible
carbohydrates and Fat (2.25). Feeds richer in protein have narrow nutritive ratio. Rations
with wide NR (1:9) are suitable for idle horses and cattle; a medium ratio (1:6) for early
fattening, lactation and working animals, etc. and a narrow ratio (1:0.7) for young stock.
Calculations of NR of ground nut cake whose: DCP =42, DCF = 1, DEE = 6, DNFE =
NR = (DEE ×2.25 + DNEE + DCF)/ DCP = (6 × 2.25) + 14.5+1/42 =29/42 = 0.70.
A narrow ratio of 10.7
Calculation of NR of maize grain: maize has 72% TDN and 7% DCP.
NR = TDN-DCP/DCP = 82-7/7 = 75/7 = 10.7- A wide NR of 1:10.7. It means for each
kg of DCP, maize contains 10:7 kg digestible non protein nutrients.
Physiological Fuel Values (PFVs): It is the portion of gross energy which is available
for transformation in the body. It is almost equal to ME. These are derived by multiplying
the gross energy values with their digestibility coefficients. In case of protein 1.25 kcal
per gram is subtracted from GE of protein as an allowance for the loss of energy thru
urine. The carbohydrate has GE (kcal/g) of 4.15 and digestibility coefficient of 98%; its
PFV (kcal/g) = 4; the GE of protein is (5.65 – 1.25) = 4.4 and Dig-coefficient of 92; its
PFV = 4; and GE of fat = 9.4; DC = 95; its PFV = 9 kcal/g.
Nutrition Value Index (NVI): It is obtained by multiplying the intake relative to some
defined standard forage which is given a value of 100 and TDN value of Roughage. The
consumption of standard forage is 80 g per kg metahohic body size. If the daily dry
matter intake of a test roughage is 1.1kg for a ram of 50 kg body weight, then the
consumption of roughage per kg matahohic body size is 1.1/50 0.75=1.1/18=58.5g. The
relative intake of the test roughage is 58.5×100/80=73%. The TDN of the test roughage is
60%. Then NVI=73×60/100=43.8%.
Definition: Animal feed technology may be defined as the application of physical,
chemical, biochemical, biological and engineering techniques to increase the nutrient
utilization of feeds and fodders.
Primary reasons for processing feeds:
1. To improve feed efficiency: Routenly as much as 10% and occasionally by as
much as 15 to 20% by processing grains.
2. To alter particle size: By grinding, pelleting, cubing, chaffing etc. to increase
intake, digestibility, prevent selectivity and improve handling efficiency.
3. To change moisture content: To make it safer to store (reduce to 10% level); more
palatable, more digestible.
4. To change the density of feed: Bulky feeds reduce feed intake. These are
sometimes prepared for the purpose of limiting energy intake especially for
horses. Grains are flaked rather than ground or pelleted. Roughages density may
be increased to economize transport, increase intake and digestibility, through
pelleting or cubing. It also reduces storage space requirements.
5. To change palatability: Molasses, flavors and fats are added, while higher salts
addition may reduce intake.
6. To increase nutrient content: By ammoniation of roughages, etc
7. To increase nutrient availability: through gelatinization of starch. Pelleting
increases P utilization in chicken.
8. To detoxify ingredients: Reduction in gossypol through heat treatment. Heating
soybeans to destroy trypsin and chymotrypsin inhibitors. Detoxify linseed meal
by allowing it to stand for 12 to 18 hours in two to three parts water at 22 to 37o
9. To improve keeping qualities: High moisture grains may be preserved by either
drying or chemical treatment (adding organic acids) or storing in oxygen limiting
silos. Green fodders are conserved as silage or hay.
10. To lesson moulds, salmonella, etc: Proper harvesting, drying and storage are
important in lessening aflatoxin contamination and toxin production. Propionic
and acetic acids will inhibit mould growth. Treatment with ammonia or
ammonium hydroxide will detoxify feeds.
Processing Methods of Grains:
A). Dry Processing Methods:
2). Dry Rolling
B). Wet Processing Methods:
2). Steam rolling
3). Steam flaking
4). Pressure cooking
A) Dry Processing Methods
1. Grinding: Is a process of particle size reduction. It is the simplest and least
expensive. It is a prerequisite for maxing, pelleting or extruding. It is usually
accomplished by means of a hammer mill. Very fine grinding makes feeds dusty
and lowers palatability. Due to fine grinding, the propionic acid content is
increased, resulting in reduced milk. But in beef cattle the propionate helps in
better fattening and good growth.
Advantages of Grinding:
1. Increases the particle numbers and thereby increase surface area which facilitates
2. Improves feed utilization and animal performance.
3. Helps in uniform mixing
4. Pelleting and extruding will be easy, more affective and efficient.
5. Segregation of ingredients is avoided.
6. Selective feeding is minimized and wastage reduced.
7. Palatability improved.
8. Energy needed for mastication is decreased.
9. Feed passage time decreased; feed consumption increased; however, in ruminants
fiber digestibility is reduced.
Particle size of ground feed is expressed as modulus of uniformity which is expressed as
a ratio of coarse, medium and fine particles in ground feed. The optimum ratio is 1:6:3.
2. Dry Rolling: Rolled or cracked grains are usually prepared by passing the grain
through a roller mill. The physical proportion of dry rolled or cracked grain would
be similar to grains coarsely ground in hammer mill. Wheat and barley are
normally dry rolled for beef cattle.
3. Popping or Puffing: Is produced by the action of dry heat (370-425o
C) for 15 to
30 seconds, which improves starch digestibility in rumen. Popped grains have less
moisture (3%) and are bulky; and it increases palatability and feed consumption
(5-10%); as well as digestibility.
4. Micromizing: It is similar to puffing except that heat is furnished in the form of
infra-red energy of microwaves. The grain is them rolled to produce a uniform
5. Extruding: It has become important part of the feed industry in the production of
pet and fish feeds; lab-animals feeds; in the gelatinization of cereals; cooking of
soybean and pulses for content of growth inhibitors. This technology is also used
for cooking meat, fish and feather meals for control of salmonella; the cooking of
cereals/starch with urea for ruminants, etc.
6. Roasting: Is accomplished by passing the grain thru flames (~150o
C). Roasting of
whole soybeans inactivates inhibitory factors.
B). Wet Processing Methods
1. Soaking: Soaking of mustard cake, neemseed cake in water and offering of
filtered product eliminates the toxic factors.
2. Steam Rolling: For steam preconditioning at atmospheric pressure, grain is
subjected to live steam for 8 to 20 minutes and temperature and moisture content
of grain are 10o
C and 16-20%, respectively. In case of pressure (20 -60 psi)
preconditioning, grain is subjected for 50 seconds to 2 minutes. Temperature and
moisture of the grain are 120-150o
C and 18-258% respectively. It increases
gelatinization of starch to 45-50%. Steam rolled grains are usually less dusty than
dry rolled grains.
3. Steam Processing and Flaking: After steam treatment, grain is passed through
the roller mill. If flaked material is to be stored for more than one day, it must be
4. Pressure Cooking: Is similar to steam processed and flaked grain. Grains are
cooked with live steam at 50 psi for 1.5 minutes in air tight pressure chambers.
Temperature of 300o
F is obtained. The capacity of roller mill to handle pressure
cooked grain is about 4 times that of pressure cooking. There flakes are less
5. Exploding: It is accomplished by subjecting the grain to high pressure steam (to
250 psi) for a very short time (20 seconds) followed by sudden decrease to
atmospheric pressure. It produces low density product.
6. Reconstitution: It is mature grain (10% moisture) to which water is added to
raise moisture level to 25-30% and the wet product is stored in an oxygen-limiting
silo for 14-21 days prior to feeding. It increases the solubility of the grain protein.
7. Pelleting: These feeds are agglomerated feeds formed by extruding individual
ingredients or mixtures by compacting and forcing thru disc openings by any
mechanical process. The purpose of pelleting is to reduce dust and make feed
more palatable; easy to handle by affliction of optimum amounts of heat moisture
and pressure. The normal size of pellets is 3.9 mm to 19mm, through the
maximum used pellet diameter is 6.25 to 9.4 mm, the shape is mostly cylindrical.
Pelleting increases the palatability and thereby improves feed intake and improves
feeding value especially of roughages.
8. Dehydration: Green forages such as alfalfas/Lucerne can be preserved at high
temperature (60-1500oF) in a dehydrator for a short time (3-5 mim). It is usually
done with the young, growing and good quality forage.
It retains maximum amount of DM and CP and there is no loss of leaves. There is a loss
of carotene (5-15%). These pellets of alfalfa (17% CP) are usually used as supplement to
Bulk Density: Roughages have low bulk density compared to concentrates. Grinding
roughages increase their density significantly. The increase in bulk density due to
pelleting of mash feed range from 29 to 135% depending on the level and type of
Effect of Processing on Bulk Density of Several Roughages
Bulk Density (kg/m3)
Name Chapped Ground Pelleted
Sorghum Stover 81.7 133.0 333
Maize Stover 59 103 344
Cotton Straw - 130 311
Sunflower Straw - 167 319
Cotton seed hulls2
148 196 356
104 185 331
148 233 359
56 100 244
1. Ground is hammer mill (40 HP) though 8 mm sieve.
Densification of Crop Residues, Grasses and Tree Leaves
High volume low value crop residues can be densified with the help of bailing machines
to economize their transportation and storage. On an overage, 15 sq. ft. of space will
accommodate about one ton of concentrates when they are stacked up to a height of 10 ft.
Space required for storing various feed (pounds/cubic fit-cubic feet/ten)
Hay, loose- 4.5-456; Hay, baled loose-10-200; Hay, baled tight -25-80; Hay, chuffed- 10-
209; Straw, loose - 4-512; Straw, baled- 22-167; Barley- 39-51; Corn, cracked- 40-50;
Oats- 26-77; Wheat- 48-42; Soybeans- 50-40; most concentrates = 45-44.
Feed Mixing Plant:
It has following machinery:
1. Hammer Mills: Are versatile grinding machines for producing with mechanical
hammers. Ground material is drawn out through a sieve located at the base of the
chamber. Fineness depends on size of screen used.
Hammer mills are of two types:
1. Pneumatic conveying
2. Gravity fall.
In pneumatic mills, the ground material is pneumatically conveyed to a cyclone collector
where it is disengaged and collected in begs. The feeding and bagging are at a level
above ground. For 6-8 tons capacity per 8 hours a 7.5 HP motor is used.
In gravity fall mills the ground material directly fells from the bottom opening into a pit.
For 6-8 ton/8 hours capacity, 5 HP is needed. The capacity of the mill is based on
grinding of maize on 5/16 hole screen.
Mixers: Generally horizontal mixers have low capacity and need more power, compared
to vertical mixers.
Conveying systems: Bucket elevators are shaped to hold the material and elevate to the
required height. For 1.5 to 2.5 tons/hour a 1-HP motor will be sufficient; and for 3 to 5
tons/- 1.5 HP.
Magnetic Separators: Are used for arresting ferrous trash from feed ingredients and
final mixed feeds. Plate magnet is kept in the feeding hoper of hammer mill and a grid
magnet is drum magnet kept at the mixed feed discharge chute to arrest the ferrous trash.
Pellet Mill: Pelleting increase the cost of machinery and involvement of high energy.
Capacity Mill motor HP Feeder motor HP
0.75 to 1 ton/h 35-40 2
1.5 to 2 tons/h 50-60 2
5 to 10 tons/h 120 HP
(at max. production)
Proportional Motor size and cost (% of total) for Feed Milling (Mill of 2 tons/hr)
Unit/operation Motors size (%) Unit cost (%)
Weighing - 7
Elevator/Angers 3 7
Holding bins - 5
Grinding 34 13
Mixing (Horzintal) 10 12
Pelleting 43 17
Steam Production 1 11
Pellet Cooling 9 11
Bag-off weigh - 7
Electrical control system - 10
Total 10 (110kw) 100
Method of improving the Feeding value of poor quality roughages
A. Supplementation with deficient nutrients: To correct nutrient imbalances and
thereby create optimum rumen conditions for efficient microbial fermentation.
1. Enrichment with molasses and urea
2. Ensiling with feces and urine; poultry waste, etc.
3. Supplementation with green fodder and legume straws.
4. Supplementation with urea-molasses blocks or liquid supplements or
Poor quality roughages can be improved by: Physical, chemical, physio-chemical and
Physical methods include: soaking, chapping, grinding, pelleting, wafering, steam under
pressure, irradiation, etc.
Chemical methods include: Alkali (Naoh, Ca (OH)2, KOH, NH4Oh); ammonia, gaseous
ammonia, acids ( H2So4, HNO3), salts (Na2Co3, Nacl); gases (chlorine, So2), Oxidizing
agents (H2O2, O3)
Physico-chemical methods include: NaoH/pelleting; NaoH/steam;
Biological Methods include: Enzymes, rot fungi, mushroom.
Physical Treatments: Soaking of straws increases DMI and VFA production but has no
effect on digestibility. The paddy straw is rich in oxalates, which are removed through
soaking and may improve nutritive value and Ca retention. Chopping of rice straw or
maize stores increases DMI of roughages.
Chaffing: By chaffing selective feeding and wastage are minimized. The hand operated
sickle type chaffy cutter can chaff 75-1010 kg/hr at 40 RPM. A power driver chaff cutter
can chaff 200-250 kg/hr at 100 RPM with 0.75kw. Chaff cutters working on 5 HP or 10
HP are useful for medium size to big doing farms. An output of 1000 to 2000 kg/hr with
5 to 10 HP motor (output depends or quality and condition of the fodder).
Process flow diagram for mash or pelleted feed production:
Feed ingredients receiving quality control lab inventory control (warhorse/storage)
conveying (separators and conveyors) Grinding (hammer or roller mills) Proportioning
(weighing betching) Mixing (horizontal/vertical feed nixies) storage and dispatching
conditioning) steam addition, etc) pelleting (pellet mill) cooling (pellet cooler) storage &
Pelleting of feeds is accomplished by storing mixed feed ingredients through a chamber
with holes (pellet die). As the extruded material leaves the die, it is cut off by Kinross to
pellets of a predetermined length. The characteristic of an ingredient that control how it
will react in pelleting are called its functional properties.
Normally the feed is preconditioned with steam before entering the pellet mill. Steam
releases natural adhesive properties in feeds to facilitate pelleting; wheat and its by-
products contain endosperm proteins with good functional properties for pelleting. The
endosperm proteins of triticale, rye and barley also react with water to increase viscosity,
but those of corn, sorghum, millet, rice and oats do not. The glucose and pentosans in
barley, ray and oats have viscous properties when wet, improving pellet quality. Added
fats at levels above 5% tend to cause pellet crumbling. Molasses increase the palatability
Sucrose, milk sugar, whey and dried milk powder will begin to caramelize at
f. They become hard and glossy and plug the equipment. Availability
of phytate P in grains is increased by steam pelleting. On the other hand, there may be
destruction of heat labile nutrients, such as vitamin A. With animals that readily consume
a diet in either the mash or pelleted form, pelleting in generally not economically
If horses or cattle are fed whole grains, a significant protein will pass through the gut
undigested, whereas sheep masticate their feed more finely so most grains and seeds are
subject to digestion. As a general rule course grinding is preferable to fine grinding.
Extruders are machines in which soybeans or other oilseeds like cotton seed etc are
forced thru tapered die. The frictional pressure causes sufficient heating to inactivate
When proteins are heat-treated, proteins and amino acid bioavailability may be reduced
as a result of the browig or maillerd reaction.
During processing dry grains usually require a maximum slope angle to sustain good
flow. Pelleted products require a maximum slope angle of 50o
to maintain flow. Flower
and corn milling products and protein meals account for the majority of the soft feed
ingredients, and require a minimum slope angle of 600
to sustain good flow.
Material processing is any procedure to change the physical characteristic of an
ingredient to improve its blending characteristic or nutrient availability. Consumer
equipments used are hammer and roller mill.
The major reason for grinding are: expose greater surface areas for digestion improve
mixing characteristic, mixer pelleting efficiency and quality and satisfy customer
Vertical mixers may have one or two elevating source. Some advantages of vertical
mixers are: relatively expensive, lower installation cost, require less space. The
disadvantages are: require longer mixing time; less liquid can be added; clean is difficult.
Under and overfilling mixes inhibits mixing, and most mixes should be filled to two-
A force of 50, 75, or 100 tones is employed to form a block of a specified weight and
dimension, in a molding chamber of a block machine.
Quality Assurance: It stretches from the initial concept through ingredient
specifications, formulation of feeds, manufacturing and distribution, feeding trials,
customer service, employee commitment and dedication to quality products. The
assurance of high quality begins with an effective quality control program, which has
several critical components like sampling, lab. testing, physical testing.
Sampling: No analysis can be better than the sample from which it was made.
Laboratory Testing: Is the process of measuring specific components of a feed ingredient
or mixed feed to assure its quality.
Conservation of fodders through Silage and Hay Making:
When green fodders are in plenty they can be conserved as silage or hay to meet the
demands during leave period. Silage can be defined as a green material produced by
controlled anaerobic fermentation of green fodder. It is the succulent roughage pressured
more or less in its original condition. The process of conserving green fodder is called as
ensilage. Silo is the receptacle in which silage is made. The best silages are moist, soft
but not slimy and fragrant in their own characteristic way. Most palatable and nutritious
silage can be made from crops that are cut at the right stage with a dry matter of 25 to
35% A dark brown color indicates excessive heating.
Crop Suitable for Silage Making:
Crop rick in soluble sugars/carbohydrates are most suitable e.g. maize, sorghum, millet,
oats, etc. Cultivated and natural grasses can give good silage by adding 3 to 3.5%
molasses in them. For making silage of mixture of grasses or cereals plus legumes, a
mixture of 3:1 ratio is recommended. Dry forage and unwilted leafy leguminous fodder
when mixed in the ratio of 1:4 can also be ensiled.
The best stage for harvesting fodder for silage is between flowing and milk stage.
Generally it is better to convert thick stemmed crops into silage and their stemmed into
hay. It is recommended to chaff to 2-4 cm length. Salt (2.5) and urea (1%) can be added
to improve palatability and CP. Proper packing is very important. It takes 4-6 weeks to
complete the process. One cubise meter can accommodate about 400 kg fodder. The silo
walls should be impermeable. If the crop has less than 30% DM, allow it to silt for 3-4
hours before filling the silo. Silo filling should be avoided on raining days. Trampling
should be done properly either with men or tractor or bullocks. At the top fodder should
be packed 3-4 feet above the ground level. Sides, bottom and top of silo may be covered
with poor quality roughages.
When fodder contains 65 to 75% moisture and sufficient sngass anaerobic lactic acid
bacteria become active to produce good quality silage. If the acidity rises to about 1% at
the start itself, the silage will be good, and lactic acid checks the activity of under
available organisms (pH around 4) like bacteria producing butyric acid.
If forage is too rich in proteins, butyric acid type fermentation will dominate. Prutyric
acid has a sharp, disagreeable odder and silage is not relished. Molasses, salt, cereal
grains, citrus pulp, etc act as preservations and enhance feeding value of silage.
Exclusion of air from the silo minimize nutrients loss; initiates growth of lactic acid
producing bacteria rapidly; prevents overheating of silage; reduces activity of moulds.
When temperature in the silo is moderate, the stage tends to be yellowish or brownish
green or even golden in color. When temperature in the silo is high, silage gets dark
brown or black.
Grasses are low in soluble sugars and legumes have higher moisture, proteins and
minerals which raise the buffering capacity remitting in low quality silage. In general
ether extract, CF, CP and NFE contents of silage can be very similar to the raw crop from
which silage was made.
A very good silage will have acidic taste and odour, free from butyric acid, moulds,
sliminess, a pH range of 3.5-4.2 and ammonia-N less them 10% of the total N, and a
lactic acid content of 1-2%. A good silage may have < 0.2% butyric acid; pH 402-405
and ammonia N of 10-15% of total N. Fair silage may have some moulds, pH 408 and
more 20% ammonical N of total N.
Haylage: Material wilted to 40-45% DM before ensiling is called haylage. For making
straw haylage dissolve one kg urea and 105kg mineral mixture in 20kg water and mix
with 9705kg of chaffed straw and store in silo pits. After about 2 months haylage will be
Wastelage: A silage containing poultry droppings, poultry litter, dung etc. for ensiling of
straw or maize stoves, mix 40kg dwppings/dung, 10kg molasses, 1kg mineral mixture,
0.5kg salt; 48kg straw in about 22 litxes of water and evsile for weeks.
Hay: Forages cut before they are fully ripe and dried (12-14% moisture) for storage and
subsequent feeding. Hay is more nutritious and palatable than straws or stovers. All thin
stemmed grasses and legumes are good for hay making. However, thick-stemmed fodders
be chapped for quick drying. The best time to cut a crop for hay making is when it is 1/3
to ½ in blossom; cereals when grain is in the milk stage, while in legumes.
When pods are in tender state. The protein of legumes is of higher quality as compared to
other plants, and is rich in calcium and more palatable. Non-legumes are rich in
carbohydrates, and their per acre yield is more than legumes and can be grown easily.
The losses in nutritive value in hay making are: due to leaves shattering; losses of
vitamins due to bleaching and fermentation, and losses of soluble nutrients due to heavy
rains. Exposure of green plants to sun deceases carotene (pro vitamin A). However, such
hays are good source of vit D2. Leaching causes loss of proteins soluble carbohydrates
and other soluble nutrients. Total losses in hay making: DM=20-30% in legumes and 10-
15% in grasses; 28% proteins; 90% carotene and 25% in energy. A moisture level of 12-
14% is desired before starching. Hay preservatives, such as organic acids, especially
provinic acid, inhibit mold growth and allow bailing at higher moisture content. After hay
is cut, proteases in plants break down proteins to amino acids, which are water soluble. If
hay is not sufficiently dry when put into storage, it may heat up. The heating is due to
microbial respiration (heat of fermentation).
Excessive heat results in non-enzymatic browning, which is a reaction between protein
and carbohydrate; which reduces availability of protein. The degree of heat damage can
be measured by analyzing the N content of ADF. As the ADF-N increases, forage
digestibility decreases. When the amount of ADF-bond N exceeds approximately 30% of
total N, the hay has received detrimental heat damage. Moist hay undergoes two periods
of heating. The first appears a few days after storage, and is due to plant cell respiration.
The maximum temperature reached is about 35o
C. The second temperature rise is due to
manorial activity, due to growth of fungi. High temperatures may be reached (60o
F) inside the stack, and should be checked frequently. If it reaches 160o
F, it should
be checked hourly. If it reaches 180o
F, it is likely to ignite and should be reonved from
the barn with for-fighting equipment standing by. When hot hay is exposed to oxygen, it
may spontaneously ignite.
Hay is primarily a cattle, buffalo sheep and horses feed, although dehydrated alfalfa may
be included in poultry rations. Average quality hay has 25 to 35% CF and 45 to 55%
TDN on as-fed basis, whereas concentrates as corn and wheat contain 2 to 3% CF and
80% TDN. Dry feed is essential for the proper functioning of the digestive tract. Hay is
often used as a supplement to posture and succulent silages. It also speeds up the
development of the rumen function of the young calves; lessens the incidence of
displaced abomasums in cattle, an prevents a lowering of milk fat content, unless it is
finely ground. Good quality hay is a hedge against high concentrate prices. In ruminant
rations, hay is primarily a source of energy, but the legumes also serve as a source of
Use of Low Quality Crop Residues
Low quality fibrous crop residues include straws, sugarcane baggasse, hulls, corn cake,
etc. These are very low in digestible energy and protein and are highly lignified. There
slow turnover in the rumen results in rumen fill becoming a limiting factor. Crop residues
contain insufficient nitrogen to support adequate microbial growth in the rumen.
Treatments to improve utilization of crop residues:
1. Chemical Treatment: Lignifications of the cell wall material is the main factor
responsible for the very low digestibility of fibers crop residues. Lignin is very
indigestible and by encrusting cellulose and other cell wall contents, impedes their
digestion too. However, lignin is very respectable to degradation by oxidation and is
destroyed by oxidizing agents such as hypochlorite and sulfites. These products are used
in the treatment of wood pulp to isolate cellulose for the purposes of paper manufacture.
Alkali dissolves lignin and renders the cell wall constituents susceptible to several
disadvantages in addition to cost: the need for supplemental nitrogen, the increased
sodium load on the animal, sodium contamination of soil, and the hazardous nature of the
An alternative is ammoniation. Ammonia treatment, either as ammonium hydroxide or
gaseous ammonia is effective in dissolving lignin, and improving fiber digestibility. It
also provides a source of supplementary nitrogen. Ammonia is an effective preservative,
and is safer and easier to use. The color of the treated straw is changed to intense yellow-
brown; and is more easily reduced to small particle size, facilitating its digestion.
Urea can be used as a source of ammonia, and most roughage have sufficient bacterial
urease present to convert urea to ammonia. Ammoniation reduces effects of aflatoxins. It
also reduces glucosinolates is mustard meal.
Toxicity of Ammoniated Roughages:
Ammoniation of feeds may produce toxins and toxicity symptoms in animals consuming
such treated feed.
This toxicity has been named as bovine hysteine, bovine bonkers, ammoniated hay toxic-
sis, hyper excitability, or crazy cow syndrome. Neurological signs, such as hyperactivity,
incardination, tremors and convulsions occur in affected animals. Cattle may become
extremely nervous and difficult to handle. Affected animals may suddenly gallop in
circles and run into fences, gates, and other objects, often causing them selves injury. The
causations factor appears to be a 4-methyl-imidizole, formed by the reaction between
reducing sugars e.g. glucose and ammonia in the presence of heat. Toxicity does not
occur if the temperature of the ammoniated roughages remains below 70
ammoniation. Ammoniation of molasses may also produce bovine hysteine. Because of
the involvement of reducing sugars, amoniation of good quality roughages with abundant
reserves of cartbohyohates should be avoided.
Other Chemical Treatment:
Treatment of low quality roughages with alkaline hydrogen peroxide solution increase
digestibility. In this treatment, the lignin carbohydrate bends are disrupted, which
increases accessibility of the cellulose to cellulolytic enzymes, increasing cellulose
digestion. Treatment of roughages with ozone has also been shown to degrade lignin and
improve fiber digestibility.
The digestibility of low-quality roughages can be improved by grinding or chopping the
material. However, these benefits are usually offset by a more rapid passage of small
particles form the rumen, escaping microbial digestion. The major benefits of chopping
are reduced feed wastage.
Lignin can also be degraded by various aerobic fungi and bacteria.
Improvement of the Rumen Environment:
Low quality roughages lack adequate fermentable nitrogen, true protein readily available
carbohydrates, and minerals for optimal microbial activity. Slow rates of fiber digestion
and outflow from the rumen are major constraints to increasing voluntary intake of poor-
quality roughages. Supplementation of low-quality roughage with ground alfalfa hay
improves fiber digestibility and rumen environment parameters, such as concentration of
branched-chain fatty acids and ruminal ammonia nitrogen. Readily fermentable cell wall
constituents of alfalfa might stimulate cellulolytic microbes with colonization of the
poor-quality roughage. The positive effects of by pass protein on intake of low-quality
roughages are well-known.
Feed additives and their use in livestock feeding:
Feed additive is an ingredient or combination of ingredients added to the basic feed mix
to full fill the specific used. It may also be defined as any chemical incorporate in an
animal feed for the purpose of improving rate of gain, feed efficiency, or preventing and
controlling disease. A feed additive need not to be a drug.
Types of Feed Additives:
Feed additives can be a classified into nutrient feed additives e.g. amino acid, minerals
and vitamins, and non-nutrient feed additives e.g. antibiotics, hormones, ammonia
modulators, coccidiostate, enzymes, probiotics, yeast acidifiers, antioxidants, mycotoxin
binders, anticaking agents, feed preservatives, plavoring agents, coloring agents, pellet
binders, dietary baffers, methane inhibitors, propionate promoters, defamating agents,
heptoses and bloat controlling agents, surfactants, sweetening agents tranquilizers,
emulsifiers and stabilizers, etc.
Advantages of Feed Additives:
1. Improve feed quality and palatability.
2. Improve animal performance
3. Improve the final product
4. Economize the production costs
Negative aspects of Feed Additives:
Hormones and antibiotic have residual effects in meat, milk and eggs. Feeding of low
concentration of antibiotics may favour the proliferation of antibiotic resistant
microngamises. Use of antibiotic in ruminants feed is not common in Pakistan.
Antimicrobial feed additives are included in the diets for the prevention and control of
coccidiosis, etc. and to improve growth, efficiency of feed utilization, livability and egg
These are produced by several strains of streptomyces species e.g. Monensin, Lasalocid,
Salinomycine, Hysocellin, which are antimicrobial compounds. Morensin is an
anticoccidial agent for broilers, lambs and beef cattle. It improves feed efficiency and not
growth. Heifers having more than 180 kg body weight can be fed 50 to 100 mg/head/day
by mixing in about 500 grams of feed. It impact is better in low protein diets.
Effect of ionophores on Rumen Fermentation:
1. It increases the rumen propionate and decease acetate concentration.
2. It deceases methane production
3. Depress the activity of some rumen enzymes like proteases, deaminases, and
4. Decrease the passage rate of feed; thus increaring the ME value per unit of feed
intake. (10%). Both monensin and lasalocid inhibit the growth of ruminal
microbes which produce acetate. Butyrate, lactate. Formate and hydrogen as
major and products. Other organisms which produce succnate and propionate or
utilize lactic acid would grow rapidly in the preauce of ionophores. The
production of increased levels of propionic acid in the rumen is related to
improved animal performance. Propionate has protein spening effect and stinulate
body protese synthesis and thus improves growth promoting activity.
Lasalocid (Trade Name: Bovitec):
It is produced by fungi streptomycin lasoliensis and is more protest than monensin. It acts
against hydrogen producing bacteria and results in higher propionate production. Its dose
is 1 mg per kg body weight or similar to monensin.
Benefits of growth promoting antibiotics in animal feeds include: better weight gain,
higher feed conversion ratio and less manure with lower N and P content. Tetracyclins,
oxytetracyclins and chlortetracyclins are absorbable antibiotics. Nonabsorbable
antibiotics are zinc bacitracin, anoporcin, monensin, virginiamycin, etc which have
beneficial effects on the microflora of the intestinal tract. As per the latest European
union regulation (folloved for Setember 1999) only monensin, salinomycin, flevomycin
and avilamycin are the from feed grade pharmacentrial antibiotics remaining on the
Arsenicals improve growth of broilers and such birds have bright red combs and wattles.
Arsenicals must be removed from the feed 5 days before slaughter. Accumulation of
arsenic in eggs and tissues is proporational to the amount in the ration and well below the
allowable levels. Arsanilic acid is tolerated upto 0.1% in the diet of chicks and upto
0.02% in the diet of turkeys. Arsenicals should not be included in the rations of the ducks
The active principles secreted by the endocrine glands into the blood for transporation to
target organs and tissues are known as hormone. The two broad types of hormones
1. Anabotic hormones e/g/ somatotropin, thyroxine and androgens.
2. Catabolic hormones e.g. oestrogens, glucocorticoids.
Hormones as carcass modifiers:
Intact males produce less fat and leaner from a given feed than either the females or the
castrate males. Bulls contain less subcutaneons fat intermusuclar fat than stears. Anabolic
agent’s evhance nitrogen retention in the body and particularly in the muscle, and result
in production of leaver carcasses. Androgens are mainly used in females and castrated
males while estrogens are used in males.
These are banned in EU since 1989, because of health problems they might cause. These
include: oestradiol, tranbolone acetrate (TBA), Zeanol (Ralgro)+TBA.
It is a polypeptide and therefore not orally actic and it is species specific. Hence the little,
if any, sometotropin present in animal products get degraded in the GI tract and thus has
no influence on human health. Somatotropin and growth hormone (GH) can be used
interchangeably. The secretion of this hormone is enhanced following feeding of protein.
Somatotropin influences the biosynthesis of protein in the muscles; increase N setention;
increases skeletal growth and improves growth and milk production.
Exogenous Bovine Somatotropin (BST) injections:
A greater negative energy balance of often observed in cows during the first few weeks
after beginning the administration of bST, but cows gradually increase their feed intake to
obtain the required nutrients for body weight gain and increased milk production. High
yielding cows treated with daily s/c injections of b St (12-50g) gave 20 to 40% increase
in milk yield and 12-14% increased feed efficiency. The increase in milk yield were
associated with increase in feed intake.
The availability of slow relaease device of bST has eliminated the necessity for daily
injection. Lactating cows injected 640 mg bST at 28 Day intervals for a period of 112
days gaine 12 to 15% higher milk yield over control animals. Levels of ST in milk
produced by treated cows are axcedingly low and constitute no threat to the human
consumer. In beef cattel steroid implants and somatotsopin produced additive increases in
performance of finishing steers. In growing lambs chronic administration of ST for 12
weeks led to a 20% increase in rate of daily gain. However, some negative impacts on
reproductive performance have been reported.
Growth Promoters for Fattening Ruminants:
In the EU, the recommended doses for fattening cattle are 20-60mg/kg feed for monensin
with optimum of 30. Ionospheres improve average daily gain and feed conversion
efficiency of growing kids by 10%. Ionophores supprescoccidisive; increase
propionate /acetate ratio.
Amprolin, clopridol, hasalocid sodium, monensin sodium, slinomycine, robenidine,
meduremicin, narecin, etc act as coccidiostates.
Several hormone implants viz oestradiol, trenbolone and testosterone are used in animal
production, but are banned in EU.
Anabolic steroids and growth hormone use has been banned in the EU, and also banned
meat imported from countries such as USA, when growth hormone is used to achieve
improved efficiency and leaner carcasses.
Feed Enzyme Additives:
These act as biocatalysts to assist the digestion process and support the utilization of
nutrients that otherwise go unused.
The predominant non-starch polysaccharides in cercal grains are cellulose, arabinoxylans
Feed enzymes such as B-glucanases and xylanases have enabled barley or wheat in
poultry diets upto 50 or 50%. Arabinases, xylanases and pectinases breakdown the
arabinoxylans and pectin’s present in sunflower seed meal, rapeseed meal, etc. and
release the protein and other nutrients; and bring the nutritional value of sunflower meal
equal to soybean meal.
A multi-enzyme preparation with cellulolytic and photolytic activity (celluloses, B-
glucanases and protease) can degrade the structural polysaccharides and proteins. Phytase
enzyme helps to increase the utilization of phytin P by poultry etc.
“Fibrozyme”, (alltech) in the first feed-grade enzyme that is rumen stable. It significantly
increases DM digestibility VFA production and carbohydrate utilization in cattle fed high
amounts of fiber. Feeds containing fibrozyme can be pelleted with only a slight loss in
Probiotics, Yeast Culture and Acidifiers
Probiotics are defined as “organisms and substances which contribute to intestinal
microbial balance”. The terms probiotic means “for life” in contrast with the term
antibiotic means “against life”.
Protiotics are advocated as an alternative to antibiotics for growth promotion. Probiotics
are live cultures of non-pathogenic organisms which are administer orally. Later
probiotics were redefined as live microbial feed supplements which beneficially affect
the host animal by improving its intestinal microbial balance. Probiotics are available in
the form of oral pastes, water dispersible powders or liquids or directly fed feed additives
and include microbial cells, microbial cultures and microbial metabolites. Most probiotics
get destroyed by upto 80% in the presence of antibiotics. The term “pronatrient” is used
in place of probiotics. The US Food and Drug Administration used the term direct fed
microbial (DFM) instead of probiotic.
Micro-organisms used as Probiotics:
Some important are: lactobacillus acidophilus, L.bifidus, :. Bulgaricus, L. casei. L.
fermentrim, L. lactis, L. plantarum, L. ruminis, L. salivaricus, Bifido bacterium bifidum,
Aspergillus oryzae, Torulopsis, Streptococus faecuim, s. thermophilus, Saccharomyces
Lactobacillus acidophillis produce lactic acid and the enzyme amylase. Lactobacillus
casei complements the growth of L. aciclophillus. Bifido bacterium bifidum is commonly
found in mother milk and the intestine of humans and animals.
Aspergillus oryzae produce enzyme cellulose. Torulopsis is the mother culture of yeast.
The enzyme lipase is exhibited by Torulopsis. Probiotics at the specific concentration
stimulate immunity. A low pH (4-5) favours lactobacillus sp. And a high pH (6-7) is
optimal for E.coli.
Shortly after hatching, the chick has a nearly sterile digestive tract with a pH rauge of 5.5
to 6.0. So supplementation of a lactobacillus product in the water or feed along-with an
acidifying agent would be effective in controlling the coli-form proliferation.
Yeast Culture: It is known to contain compounds formerly refessed to as UFGs which
positively affect animal performance rumen bacterial concentrations increase when
fermentation products such as yeast cultures are added to the diet. Metabolites in the
fermentation products serve as nutrients for the bacteria. Byproducts of fermentation
include dried brewers yeast, dried distillers soluble, dried bacterial press cakes.
Yeast cells are destroyed by pelleting the feed, storage conditions and strong mineral
mixtures. Significant losses of variable yeast cells canals occur over time for yeast
products hold at 35o
C in paper bags. The rate of deterioration is time and temperature
Inclusion of live yeast cultures in the diet (3 to 5g/d) decreases body temperature and
respiration rate in hot, but not in cool weather. It also act by production of growth
stimulating factors in the rumen. Stabilizing rumen pH and reduction of lactic acid
production, and increasing rumen bacterial population.
Yeast culture increases rumen bacterial population, which in turn will increase flow of
microbial protein, as well as increase degradation of fiber in rumen, leading to increased
feed intake, and thus ultimately increasing animal productivity.
Yeast culture may increase milk yield (8%); with more response during early lactation.
Responses increase as the ratio of concentrate to forage in the ration increases. Total
butter fat and milk protein also increase. Inclusion of yeast in the diet of cows fed a 60%
concentrate and 40% when straw was replaced by hay. The addition of yeast culture to
diets containing 40 to 80% oat straw increased in sites NDF digestibility in steers.
Acetate was reduced which propionate was increased by yeast addition. Ruminal
protozoa numbers increased in steers fed yeast culture. Total and cellulytic bacteria were
higher in ruminal fluid of calves fed yeast culture.
White rot fungi decompose lignin or lignocelluloses with minimal degradation of
hemicelluloses and cellulose. Yeasts are always found in culture of white rot fungi. The
potential synergism between yeast (S. cerevisiae) and fungi (Armillaria heimii) had the
best potential for increasing forage digestibility. Inclusion of yeast culture diets given to
Supplementation of broilers diet with live yeast culture (1 kg/ton) may increase weight
gain and FCR. Combined use of lactobacillus and yeast culture in the feed and water may
be effective in reducing morbidity and mortality and improving growth performance and
Direct-fed microbial include:
Lactobacillus, streptococcus, Bacillus and yeast (saccharomyces cerevisiae). Lactobacilli
are delicate microbes that are unable to withstand various environmental extremes, such
as the heat and pressure of pelleting. Bacilli are very stable microbes that can survive
pelleting. Yeast and streptococcus fall somewhat between lactobacillus and bacillus in
their ability to survive pelleting. The ability of the yeast to grow in the rumen is limited,
but is able to remain alive and metabolically active in the rumen and postruminelly. DEF,
are designed to prevent or reduce E.coli scones in calves. The rational for their use in the
calf is that feeding live, non-pathogenic bacteria may displace and suppress intestinal
pathogens. DFMs may be of little benefit under good rearing conditions and husbandry
practices. Stress such as extreme weather or transportation, would more likely enhance
the potential benefits of feeding a DFM to calves.
Acidifiers: Organic acids usually are added only as preservations, but they do positively
influence performance when included at higher quantities.
Liquid acidifiers are :
1. Formic acid- 6-8kg/ton
2. Prop-ionic acid- 8-10kg/ton
Organic acids in powder form are:
1. Fumaric acid 12-15kg/ton
2. Citric acid 20-25kg/ton.
In diets for laying hens, the feed additive calcium format (1.3%), which is converted to
formic acid in the crop, offers potential benefits beyond reducing E. coli and salmonella
populations. It inhibits molds; improves consistency of droppings, resulting in fewer dirty
eggs; better calcium absorption and egg shell quality. It is stable in storage, safe in food
and the environment and without negative effects for other feed supplements, such as
vitamins, etc. Calcium format is non-corrosive, odor free and non-caustic. It approved by
EU for use as food and feed preservation.
Oxidation of feed fats causes rancidity spoiling the taste and flavor of the feeds thus a
process known as lipid per-oxidation or autoxidation these rained fat containing diets
impart undesirable off flavour in the milk and milk products. Oxidation also causes much
loss to carotenes; vitamin A and vitamin D. The use of antioxidants limits this oxidative
spoilage. Oxidation negatively affects odor, taste and nutritive value of the food, as well
as produces harmful by-products. The addition of antioxidants map up the free radicals.
Antioxidants may be natural and synthetic. National ones are vitamin E (tocopherol) and
ascorbic acid. The most common synthetic antioxidants are ethoxyquin, butyrate
hydroxyanisole (BHA) and butylated hydaroxytoluene (BHT). BHT and BHA tend to be
more effective in preventing oxidation of animal fats than of vegetable oils which
ethoxyguin is most effective in protecting both animal fats and vegetable oils.
Mycotoxin binders: these chemicals are harmful to animals and humans. The major
mycotoxin producing fungi are aspergillums, fusarium and penicillium and the toxins are
aflatoxins, zeralemone, trichothecenes, fumonisins, ochratoxin A, etc. Mycotoxin binding
agents include activated charcoal, yeast cell wall products, synthetic zeolites and mined
mineral days such as aluminosilicates, sodium betonies.
Anticaking agents: these are substances that can pick up moisture without themselves
becoming wet. They are added to dry mixes to prevent the particles clumping together
and so hup the product free flowing. Anticaking agents include: calcium star-ate, calcium
phosphate ferrous ammonium citrate, yellow prussiate of soda, potassium or sodium
ferrocyanide, magnesium oxide, kaolin, ball clay, sodium aluminum silicates, hydrated
sodium calcium alluminosilicate (HSCAS), calcium aluminum silicate, etc.
Preservatives: The aim of preservatives is to prevent microbial spoilage. e.g. nisin,
benzoic acid, methyl-4-hydroxybenzoate, cthyl-4-nitrate, prop-ionic acid, sorbic acid and
Antifungal agents: Sodium propionate, sodium benzoate, nystatin, etc.
Flavors are used to improve palatability and thus food appeal. Palatability and FCR are
interdependent. Flavors include species and sweetness. Taste and odor are important
properties of a food or feed by which they are recognized and enjoyed. The four basic
taste qualities are salt, sour, sweet and bitter. Commercial flavoring agents only try to
influence sweetness. Flavoring compounds are nonvolatile water soluble substances
which have little or no taste of their own, but modify or potentiate the flavor of a product,
e.g. esters, alcohols, terpenes, etc.
Flavor in Poultry Feed
Chicken possess a sense of taste but a very limited ability to small. Yet poultry accept or
reject feed according to their preference. Flavors help to improve sedimentary taste
perceptions, aid in sedimentary salivary senction, help to regulate water intake and help
to overcome stress. Hence flavors increase feed intake, improve feed efficiency and
reduce mortality, e.g. monosodium glutamate (MSG) at 0.2%. Meat, cheese, mint, anion
and garlic flavors are used in feeds for pets at less than 0.1%. Yeast products are also
used at 0.25% in combination with MSG for the improvement of dry dog food.
Capsicum, red pepper, MSG, fennel, fenugreek seed, ginger are examples of spice and
Yolk color is improved by the addition of either dried alfalfa leaf meal at 2 to 3%, if
yellow maize is not the part of the ration or synthetic carotenoid pigments. Most yellow
and red pigments synthesized in vegetable materials are a closely related group of
chemical compounds known as carotenoids. Green leafy materials are excellent sources
of xanthophylls. Alfalfa carotenoids produce yellow pigmentation of the skin and fat of
chickens also. Under normal feeding conditions, 70% of the yellow color of egg yolk is
due to xanthophylls, and most of the reminder is due to zeaxanthin. The biological
availability of xanthophylls from various feed sources is variable i.e. corn gluten meal 47
to 89%, dehyhated alfalfa 37 to 65%.
Xanthophylls are not stable compounds and can be lost from poultry feeds by oxidation
which can be protected by adding antioxidants.
Lignin is the most widely used feed binder in the world today, advantages being
improved pellet quality, greater pelleting efficiency, improved press capacity and die life,
lower power consumption, lower production costs, less frnis and feed rejections and less
dust in the mill. Sodium benonite can be used @ 2.5%. The other binders are molasses 5-
10%, calcium aluminates 0.6-1% and gnar meal 2.5-5%.
Feeding high grain diets to meat the energy requirements of high yielding i.e. over 35 kg
milk/h/d, cow’s leads to changes in rumen pH and rumen fermentation pattern. Buffers
are used to correct these changes. Sodium bicarbonate @200g/cow/d or 1.5% of grain
ration, as well as other buffers like magnesium oxide, calcium carbonate, sodium
bentonite can be used. Salt level under these conditions may be reduced to half normal.
Magnesium oxide plays a major role in the synthesis of milk fat in the udder. Dietary
requirement is =0.23% of DM intake.
Sodium bentonite prevents milk fat depression when fed @5% of the grain ration.
However, bentonite reduces availability of other minerals in the rumen and also increases
rate of passage.
Sodium bicarbonate for poultry
It is being used to improve weight gain, FCR, live ability and processing yields under
stressful conditions. For broilers used @ 1.8-2.7 kg/ton continuously. For layers @1 to
1.8 kg/ton. In layers it improves shell quality and better litter conditions. During heat
stress the dose is 3.6 to 4.5 kg/ton. Part of sodium bicarbonate can be given via water.
Methane production could be inhibited by fatty acids, particularly unsaturated FAs. Other
methane inhibitors are chloroform, carbon tetrachloride, chloral hydrate, sulphites and
Copper sulphate, sodium lauryl diethoxy sulphate, sodium lauryl sulphate, oil rich in
PUFAs and dioctyl sodium sulphosuccinate.
Ketoris controlling agents
Sodium propionate, propylene glycol
Black controlling compounds
Poloxalene (blast gnard) @10-20g/day.
Microbial growth factors
Include miacin, thiamin, branched chain fatty acids (isobutyric acid, 2-methyl butyric
acid, and isovaloric acid) and straight chain fatty acids (n-valeric acid).
Molasses, dextrin, sugar.
Hydrozyzine hydrochloride-1-2 mgs/d, Reserpine-5-10 gm/d mi.
A substance which aids in the formation of a stable mixture of two otherwise immiscible
substances (e.g fat and water) is called an emulsifier. It should have one group with and
affinity for water and another with an affinity for fat e.g. lecithin, glycosides esterifies
with acetic acid, lactic acid, citric acid, glycerol monostearate, propylene glycol
Toxins and Ant-nutritional factors present in feedstuffs
Anti-nutritional factors (ANFs) may be defined as those substances present in the diet
which by themselves or their metabolic products arising in the system interfere with the
feed utilization, reduce production or affects the health of the animal. There anti-nutrition
substances are often referred to as toxic factors because of the deleterious effects they
produce when eaten by the animals. Toxic substances of natural origin can be classified
based on their chemical proportions and on the basic of their effects on utilization of
A. According to their chemical proportion:
Protein e.g. Protease inhibitors and haemagglutinins (Lactins).
Glycosides e.g. Saponins, Cyanogens and Glucosinolates.
Phenols e.g. Gossypol, Tannins.
Miscellaneous e.g. Antimetals and Antivitamins.
B. On the basis of their effects on nutrients:
1. Substances depressing digestion or metabolic utilization of proteins e.g. Trppsin
and chymotrypssin inhibitors.
2. Substances reducing solubility or interfering with the utilization of minerals e.g.
Phytic acid, Oxalic acid, Glucosinlates and gossypal.
3. Substances increasing the requirements of certam vitamins e.g. anti-vitamin A, D,
E-K, and anti-vitamin B1, B6, B12 and nicotinic acid.
4. Substance with a negative effect on the digestion of carbohydrates, e.g. Amylose I
nhibitor, phenolic compounds and flatulence factors.
Protease inhibitors in soybean, mungbean, etc are heat labile. Trypsin inhibitor of
soybean interferes with the availability of methiomine from the raw soybean in young
chicken. The trypsin inhibitor activity of solvent extracted SBM may be destroyed by
exposure to steam for 60 minutes, or by autoclaving under the following conditions: 5 psi
for 45 minutes, 10 psi for 30 minutes and 15 psi for 20 minutes duration.
Soybean, castor bean and other legume seeds contain lectins. These are found in both
plant and animal tissue. These are able to combine with the glycoprotein components of
ABCs causing agglutination of cells. Although resistant to destruction by dry heat, but
can be inactivated by steam.
1. Saponins: These are characterized by bitter taste, farming in aqueous solution and
heamolyse ABC. Generally saponins are less important because their levels are low in
most common feed ingredients for monogastric animals. The important common forages
which cause saponin poisioning of livestock are lucern, soybean, etc. average seponin
content of leaves are twice as much as those of the stems and that the saponin content
declines as plant becomes old.
About 0.4 - 0.5% saponin in the feed can depress feed intake in birds. Egg production and
body weight are also depressed. Feeding lucern meal beyond 5-7% in poulting mash
show decreased weight gain and egg production. The effect can partly be reversed by
feeding of cotton seed oil in the diet with which saponins get binded.
Saponons are degraded by rumen microbes and hence no growth depression is noticed.
However, upon excess feeding of green lucern bloat /tympany may occur, which is due to
foam fornution in rumen which traps gas; which animal canort eliminate by belching. The
rumen distension impedes the blood flow which is responsible for respiratory failure.
Turpentine an paraffin oil are helpful in reducing bloat. For ruminates 1 to 2kg dry fodder
should be fed before letting the animals for legume pastures or before excessive feeding
of green legume fodders as a preventive measure.
2. Cyanogens. Cyanide in trace amounts is present in the plant hingolom. It occurs
mainly in the form of cyanogenic in plants the glucoside is non-toxic in the intact tissues.
These glycosides can be hyoholysed to prussic acid or hydrocyanic acid (HCN) by the
enzyme. The HCN is rapidly absorbed and some is eliminated there the lungs, but the
greater part is rapidly detoxified in the liver by conversion to thiocyanate. Excess
cynideion can cause sudden death. Ruminants are more susceptible to HCN poisioning
than horses. Cattle are most susceptible than sheep. It usually causes reduced growth;
poor feed efficiency and result in death if consumed in increased amounts. Clinical
symptoms are characterized by mental confusion, generalized Sudan peresis and
respiratory distress, abdominal pain and vomiting. Jowar and Sudan fodder and linseed
may develop toxic lench of HCN in the new growth that fodders either a period of
drought, or a period of heavy trampling or plysical damage by frost, etc. heavy nitrate
fertilization followed by an abundant irrigation or rainfall may increase the potential of
HCN poisioning of these crops.
Feeding of immature jawar green fodder should be avoided to prevent HCN poisioning.
Animals which have not shown much evidence of toxicity may be injected IV with 3g
sodium nitrate and 15g sodium thiosulphate in 200ml Hoo for cattle. For sheep 1g
sodium nitrate and 2.5g sodium thiosulphate in 50ml water.
3. Glucosinolates: Most plants of crucifer family (cabbage, turnips, rapeseed and
mustard green) contain these suds fances. These are responsible for the pungent flarns
found in plants belonging to the genus brassica. They mainly depress synthesis of thyroid
hormone (thyroscine, T4) and T3, thus producing goiter. Growth depression and
enlargement of liver and kidneys are also observed in chicks. Ruminants appear to be less
susceptible to the toxic effects of glucrinolates. High-or-low-gluosinolate cultivars of
rapeseed are available double-zero cultivars were developed in Canada.
1. Gossypol: It is present in pigment glands of leaves, stems and roots and seeds of
cotton seed. It is highly toxic to rabbits and poultry. Horses are resistant. Ruminants are
more resistant. Its toxic effects can be overcome by supplementing iron as ferrous
sulphate. Whole cotton seed contain a total of 1.09 to 1.53%, of which free form is
0.19%. The physiological effects of free gossypol are reduced appetite, loss of body
weight, accumulation of flied in the body cavaties, cardiac irregularity, reduced
haemogblin content, etc. Decrease egg size and egg hatchakility are also observed. Free
gossypol content of 0.06% depresses growth in chicks, while 0.1% cause severe effects.
In laying hens 0.15% free gossypol reduced egg production. Egg yolk will have an olive
green color. Further higher levels cause yellow, brown pigments in liver and spleen due
to destructive effects or RBC. Although treatment as in the commercial production of
CSM decrease the content of free gossypol, the availability of lysine is reduced.
2. Tannin: it is polyphenolic substance. Tannins are of 2 types i.e. (A) Hydrolysable
tannins, which can be readily hydrolyzed by water, acids, bases or enzymes; and (B)
condensed tannins which are flavonoids-polymers of flavonol. Tannin content in various
feeds (%) are: Sorghum-2 to 10%, mustard oil cake 2.5 – 3.5% and becern meal 0.1 –
Tannins are astringent and cause a dry sensation in the month. They bind the proteins and
these inhibit photolytic enzymes. High tannin content also depresses cellulose activity
and thus affects dejection of crude fiber. So tannins reduce the digestibility of protein and
dry matter. Most of the tannins are located in the seed coats; therefore, decortications of
seeds will reduce the tannin content.
Methods of detannification:
1. Physical: Sooking and cooking decrease the tannin content. Anaerobic storage of
moist sorghum grains for two and nine days resulted in 40% and 92% reduction in
2. Chemical: Addition of tannin complecing agents like polyethylene glycol (PEG)
and plyvinylpyroldone (PVP) prevent formation of complexes between tannin and
protein as well as break the already formed complex thus liberating protein. Alkalies,
formaldehyde, organic solvents like acetone, acids, H2O2 reduce the tannin content.
Sesbania grandiflora has toxic substances such as saponins, tannins, amsines, alkeloids,
Substances depressing minerals utilization.
Phylic Acid: About 67% or more of the physphorus in cercal grains is in the form of
plytin phosphorus. The availability of P from plant feeds to non-ruminants may be safely
assumed as no more than 33%. By contrast, P from inorganic mineral supplements and of
animal orgin are usually available at the rate of more than 80%. Addition of the enzyme
phytase to the ingredients of vegetable orgin can increase degistibilty considerably.
Phytase produced by rumen microbes makes phytin P available to ruminants. Phytic acid
depresses the utilization of several mineral elements such as Ca, Mg, Fe, Zn, etc.
Oxalic acid: Plant foodstuffs have higher oxalic acid than foodstuffs of animal origin.
The leaves are richer than other parts. Young leaves have smaller levels than mature
leaves. Ageing as well as over tripening of vegetables is accompanied by an increase in
the proportion of calcium oxalate. Growth and blood calcium is decreased in poolty.
Cattle fed on faddy straw or other grasses (napier, bajra, etc) containing 2% oxalate
develop a negative Ca balance but sheep do not develop at this level. Rumen microbes
(pseudomonas, streptomycin, etc) decompose much of soluble oxalic acid and to a less
extent its Ca salts. Excess oxalate (20-30 mg percent) may depress Ca absorption or may
be absorbed from the rumen into the blood stream causing hypocalcaesinra. Oxalate
poisoning in livestock results principally from ingesting oxalate-producing plants which
are very palatable to them. Oxalate poisoning in cattle and sheep are characterized by
rapid and labored respiration, depression, weakness, coma and death.
2. Antivtamins: Are organic compounds which either destroy certain vitamins or
combine and form unbearable complexes or interfere with digestive and /or metabolic
A). Antivitamin A: Raw soybean contains enzyme lipoxygenase which can be
destroyed by heating 5 minutes with steam at atmospheric pressure.
Lipoxiygenase catalyses oxidation of carotene, the precursor of vit. A
B). Antivitamin E. Present in kidney beans can produce muscular dystrophy in
chicks and lambs by reducing plasma vit. E. Autoclaving destroys it.
C). Antivitamin K: Eating sweet clover cause fatal hemorrhage in cattle. This is
known as sweet clover diseases. Dicoumarol present in sweet clover is
responsible for this. It reduces prothrombin in blood and affects its clotting.
D). Antivitamin D: Unheated soy protein affects chicks and autoclaving eliminates it.
E). Anti-pyridoxine: Found in linseed meal and affects chicks, which can be
considerably improved after water treatment and autoclaving.
F). Antiniacin: An antagonist of niacin, niacytin is fosud in maize, wheat bran, etc.
which causes perosis and growth depression.
• Nitrate poisoning in cattle is due to the consumption of nitrates present in same
• The nitrates are reduced to nitrites in the rumen.
• Then it binders oxygen transport in blood.
• In some cases, the blood becomes almost chocolate brawn with brownish
discoloration of non pigmented areas of the skin and mucous membranes.
• The pulse becomes rapid with labored breathing.
• Death may result because of anoxia.
• Non ruminants can tolerate nitrate.
• Corn stalks and oat hay were two of the feeds first reported to occasionally
contain high nitrate.
• Feed containing more than 2.2% potassium nitrate is toxic.
• Subabul (Leucaena) green forage contains a toxic amino acid, called Mimosine, at
2-5% in the leaves on DMB.
• During the digestion process this is converted to a toxic composed.
The toxicity symptoms include
Enlarged thyroid glands,
Low serum thyroxine (T4),
Low serum triiodothyronine (T3),
Weight loss and death
Abortion of pregnant animals,
and death of calves are also reported.
• Some animals develop cataract certain ruminants in Hawaii and Indonesia possess
rumen bacteria which can rapidly degrade this toxic compound and thus are not
susceptible to Leucaena toxicity.
• Mimosine toxicity is observed in ruminants if subabul constitutes more than
about 30% of the total diet DM.
• Subabul is toxic to poultry and other monogastrics animals.
• The maximum quantity of subabul leaf meal acceptable to layers is about 25%
and 5% to broilers.
• Drying at high temperature ensiling and addition of ferrous sulphate reduces the
Mimosine content of subabul.
In practice, this usually occurs only after a large amorent of urea, or a similar NPN source
which is rapidly degraded by the rumen bacteria, has been consumed. It is generally
associated with high pH values in the rumen i.e. above 7; when appropriate amounts of
ammonia are in the undissociated form, which rapidly diffuses across the rumen wall,
either into the portal system or into the peritoneal fluid and hence into the systemic blood.
The latter pathway bypasses the liver and in more important in causing toxicity. Signs of
disorder include heavy breething, ricoodination, tetany and death, occur when ammonia
N is systemic blood has increased from normal concentration of less than 1mg’litre to
more than about 7-12mg.litre. Toxicity is most likely to occur when NPN some is given
without other feed or with a poor energy source such as fiber. Under these conditions
toxic effects were seen in sheep and cattle given single doses of urea rouging from 0.3 to
0.8 g/kg body weight.
Factors that influence deteriorative change during storage:
3. Oxygen supply
4. Condition of the product.
Moisture and temperature are the principal factors for sage storage.
• The maximum moisture content at which grain can be stored safely depends on
the kind of grain, the locality in which it is stored, and the length of storage
• The maximum moisture content for safe storage in the U.S. are as follows: corn,
oats and sorghum, 13% soybeans 11%.
• The lower the temperature, higher the level of permissible moisture for storage.
• For long time storage up to 5 years the moisture level should be 2% lower.
• At low moisture content of below 9% most of the destructive insects become
inactive e.g. rice and maize weevils.
• Flow beetles on the other hared can produce progeny in flovers or in grain dust
that are extremely dry.
• Mould growth can readily develop in stored materials if the moisture content in
any one area vises above 13%.
• The increase in moisture content and temperature due to growth of frequently is
followed by rapid growth of moulds.
a). Temperature of environment:
• Speed of the most chemical reactions increase with the increasing temperature.
• Reaction is rapid at higher moisture level.
• Temperature below 15o
C retard insect reproduction.
• Temperature between 21-43o
C speed up the life processes of all
b). Temperature of stored grains:
• Low temperature offset the effects of high moisture with respect to the hazard of
mould growth and insect development.
• Insect infestation enhances the moisture content of stored feeds due to their
metabolism and can result in temperature increase up to 42oC.
• The materials with 11 to 15% moisture both insects and moulds become active
and heating occurs.
• A small local rise of temperature referred to as ‘hot spot’ will accelerate the
metabolism of insects and speed up the rate of population increase.
• This follows the growth of moulds.
3. Oxygen Supply:
• In closed storage basis de to grains respiration the concentration of Co2 increase
and the concentration of O2 decreases and the rate of respiration tends to decrease
due to limited oxygen supply.
• Ample supply of O2 supports respiration and if the rate of respiration is high
enough the heat produced in the process will exceed heat lost and spontaneous
heating will occur
4. Condition of the feed:
• The tendencies of the grain to deteriorate in storage are considerably influenced
by the condition or soundness of the product.
• Grain with broken seed coat usually is expected to harbor greater number of
mould spores and bacteria.
• Unsound grain exhibit more rapid respiration to heat in storage than in sound
grain of the same moisture content.
• Mould growth can occur in damaged grain even at lower moisture level. Electrical
conductivity of unsound grain is usually higher.
Consequences of consumption of mouldy feed:
In farm animals consumption of mycotoxin feed reduces growth efficiency, lowers feed
consumption and reproductive rates, impairs resistance to infections diseases, reduces
efficacy of vaccination, induces pathogen damage to the liver and other organs, etc.
The three major mycotoxin producing fungi are
These fungal species grow under favorable conditions in the field even before harvesting
the crop, during transport and in the storage place. These severe their metabolites i.e.
mycotoxin. In addition to being acutely toxic, some mycotoxins are now linked with
• Are a group of closely related, highly toxic, mutagenic and carcinogenic
• Aflatoxin affects liver functions and leads to unthriftiness, can low resistance to
disease and interfere with vaccination and acquired immunity in livestock, and
may also cause rectal prolapsed.
• Aflatoxins are not accumulated in animal tissues except milk.
• Lactating dairy cattle secrete 1.7% of their total aflatoxin B1 intake as aflatoxin
M1 in milk.
• So the complete feed for dairy cattle should contain a maximum of 20 ppb.
• Hens fed aflatoxin- contaminated feed laid aflatoxin- contaminated egg.
• A four to five 5 days time is required to the effect.
• Mature animals and layer birds are least susceptible to aflatoxin.
• In dairy cows they cause decreased fertility, prolonged estrus and swelling of
• Turkeys develop greatly enlarged vents with in four days.
3. Ochra-toxin A
o It can damage the kidneys and limit growth.
• There are a group of more than 150 structurally related compounds that inhibit
• The toxic effects in animals include gastrointestinal disturbances such as
vomiting, diarrhea and inflammation.
• These are also potent immune suppressive agents.
• Dairy cattle are less susceptible.
• Upto 18 ppm is acceptable in chicken rations.
• Unthriftivess, decreased feed consumption, slow growth, lowered milk
production, sterility, gastrointestinal hemorrhages and death can occur when cattle
consume rations containing T-2 and diactoxycrise not (DAS).
• Drastic and sudden decrease in egg production in laying hens has been reported
due to T-2 toxin.
• Lesions on the beak and in the month also have been reported in turkeys and