Nutrient by shakira sulehri
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  • 1. 1 Nutrient Categories 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: 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 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 roughages. Lipids 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. Minerals 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 and Sulfur. Trace minerals include: Manganese, Zinc, Iron, Copper, Molybdenum, Selenium, Iodine, Cobalt and Chromium. Vitamins
  • 2. 2 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 Regulatory Functions 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. Nutrient Requirements 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
  • 3. 3 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. Feeds Classification 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, etc. 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, etc. 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).
  • 4. 4 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. Energy Estimation 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 conducted. 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.
  • 5. 5 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.
  • 6. 6 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.
  • 7. 7 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 occur. 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 intestine. Deleterious Factors 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
  • 8. 8 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 rumen. 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. Nutrient Content: 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.
  • 9. 9 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. Nutrient Content 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 any grain. 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
  • 10. 10 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.
  • 11. 11 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 hay 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 C to 15.5o C. Kilo Calorie (kcal): Heat required to raise temperature of 1 kg of water by 1o C or = 1000 calories 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.
  • 12. 12 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 per gram. 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 = 14.5 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%.
  • 13. 13 Feed Technology 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 C. 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.
  • 14. 14 Processing Methods of Grains: A). Dry Processing Methods: 1). Grinding 2). Dry Rolling 3). Popping 4). Extruding 5). Micronizing 6). Roosting B). Wet Processing Methods: 1). Soaking 2). Steam rolling 3). Steam flaking 4). Pressure cooking 5). Exploding 6). Pelleting 7). Reconstitution 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 increased digestibility. 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
  • 15. 15 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 dense product. 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 dried. 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 brittle. 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
  • 16. 16 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 cattle. 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 roughage. 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 Groundnut hulls2 104 185 331 Maize Cobs2 148 233 359 Sugarcane Begasse2 56 100 244 1. Ground is hammer mill (40 HP) though 8 mm sieve. 2. Unprocessed. 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:
  • 17. 17 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) 3 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
  • 18. 18 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 concentrates. Poor quality roughages can be improved by: Physical, chemical, physio-chemical and biological methods. 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 & despading. 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
  • 19. 19 fats at levels above 5% tend to cause pellet crumbling. Molasses increase the palatability of feeds. Sucrose, milk sugar, whey and dried milk powder will begin to caramelize at approximately 140o 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 advantages. 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 many toxins. 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 preference. 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- thirds. 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.
  • 20. 20 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. Fermentation Process: 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.
  • 21. 21 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 ready. 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
  • 22. 22 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 C) (140o 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 protein. 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 chemical. 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:
  • 23. 23 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 C during 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. Physical Treatment 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:
  • 24. 24 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. Poultry: 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 production. Ionophore Antibiotics: 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 urease. 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):
  • 25. 25 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 approved list. 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 and gees. Hormones: 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 include: 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. Anabolic steroids: These are banned in EU since 1989, because of health problems they might cause. These include: oestradiol, tranbolone acetrate (TBA), Zeanol (Ralgro)+TBA. Somatotropin: 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
  • 26. 26 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 and betaglucans. 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 enzyme activity.
  • 27. 27 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 cervisiae. 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 dependant. 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.
  • 28. 28 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 yearling horses. 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 production. 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
  • 29. 29 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. Antioxidants: 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 sulphur dioxide. Antifungal agents: Sodium propionate, sodium benzoate, nystatin, etc. Flavoring Agents 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
  • 30. 30 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 seasoning. Pigments 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. Pellet binders 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%. Buffers 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.
  • 31. 31 Methane Inhibitors Methane production could be inhibited by fatty acids, particularly unsaturated FAs. Other methane inhibitors are chloroform, carbon tetrachloride, chloral hydrate, sulphites and nitrites, etc Defaunating agents 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). Sweetening agent Molasses, dextrin, sugar. Tranquilizers Hydrozyzine hydrochloride-1-2 mgs/d, Reserpine-5-10 gm/d mi. Emulsifiers 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 monostearate. 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 nutrients. A. According to their chemical proportion: Group-1 Protein e.g. Protease inhibitors and haemagglutinins (Lactins). Group-II Glycosides e.g. Saponins, Cyanogens and Glucosinolates. Group-III Phenols e.g. Gossypol, Tannins. Group-IV
  • 32. 32 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. Haemagglutinins (Lectins) 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. Group-II, Glycosides: 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
  • 33. 33 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. Group-III, Phenols 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 – 3%. 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:
  • 34. 34 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 tannins, respectively. 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, etc. Group-IV, Antimetals: 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 functions. 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.
  • 35. 35 F). Antiniacin: An antagonist of niacin, niacytin is fosud in maize, wheat bran, etc. which causes perosis and growth depression. Nitrate Poisoning: • Nitrate poisoning in cattle is due to the consumption of nitrates present in same grasses. • The nitrates are reduced to nitrites in the rumen. • Then it binders oxygen transport in blood.
  • 36. 36 • 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. Mimosine Toxicity: • 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  Alopecia,  Excessive salivation,  Enlarged thyroid glands,  Low serum thyroxine (T4),  Low serum triiodothyronine (T3),  Esophageal lesions,  Poor appetite,  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. Ammonia Toxicity: 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
  • 37. 37 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.
  • 38. 38 Factors that influence deteriorative change during storage: These are 1. Moisture, 2. Temperature, 3. Oxygen supply 4. Condition of the product. Moisture and temperature are the principal factors for sage storage. 1. Moisture: • 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 period. • 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. 2. Temperature a). Temperature of environment: • Speed of the most chemical reactions increase with the increasing temperature. • Reaction is rapid at higher moisture level.
  • 39. 39 • Temperature below 15o C retard insect reproduction. • Temperature between 21-43o C speed up the life processes of all microorganisms. 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 Aspergillums, Fusarium Penicillin
  • 40. 40 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 cancers. 1. Aflatoxins • Are a group of closely related, highly toxic, mutagenic and carcinogenic compounds • 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. 2. Zeralenone: • In dairy cows they cause decreased fertility, prolonged estrus and swelling of value. • Turkeys develop greatly enlarged vents with in four days. 3. Ochra-toxin A o It can damage the kidneys and limit growth. 4. Trichothecenes: • There are a group of more than 150 structurally related compounds that inhibit protein synthesis. • 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 chicken. 5. Fumonisins:
  • 41. 41 • These have long been associated with occasional outbreaks of blind staggers in horses. • It is characterized by facial paralysis, nervousness, lowness, ataxia and inability to eat and drink. • These reduce feed intake and weight gains in chickens. Cattle, however, seem to be less susceptible. Techniques to lower the risk of mycotoxin: 1. Once the mycotoxicosis is identified as the cause, the toxin-contaminated feed should immediately be with drawn and a low fat, high quality protein ration should be offered. Increase the vitamins minerals and amino acids especially Methiomine by 30-40% over the requirements. 2. Physical segregation of the fungi infested feeds, or by diluting the contaminated feed with clean feed, or feed the suspected feed exclusively to mature animals or layers, since they are least susceptible. 3. Ammonia treatment. • Sunlight could destroy about 50% of aflatoxin in groundnut cake. • Autoclaving at 120oC with a pressure of 15 psi. • Heat has little effect on other mycotoxin including zeralenone, vomitoxin and ochratoxin. 4. Mycotoxin binding agents include yeast cell wall products e.g. • mycosorb, • hydrated sodium, • calcium, allumino-silicate (HSCAS) at 0.5 to 1% of diet;
  • 42. 42 • sodium betonies, • activated charcoal, • Synthetic zeolite, etc. Majority of these are effective against aflatoxins, followed by ochratoxin, zerolenone. Zealots and mineral days (HCAS, sodium benetonite) are capable of adsorbing or trapping aflatoxin molecules. 5. Latest technique for mycotoxin decontamination is the use of enzymes to decompose the toxin. The enzyme esterase breaks zeralenone, while enzyme epoxidase degrades Trichothecenes. Range forages • Rangelands are defined as those areas that by reason of physical limitations like low and erratic precipitation, rough topography, poor drainage or extreme temperatures are not suited to cultivation. • Such lands, therefore, serve as a source of forage for free ranging native livestock and wildlife.
  • 43. 43 • About 60% of the total geographical area of Pakistan is categorized as rangelands. • Foresting is the major land use in Northern parts of Pakistan and livestock grazing is prevalent in the forest areas. • At the national level, small ruminants obtain about 60% of their feed from rangelands, their feed by grazing rangelands. • In the province of Balochistan, nearly 90% of the total feed requirements of livestock are met from rangelands. • The total geographical area covered by rangelands of Pakistan is about 51 million hectors. • These rangelands produce approximately 25 million tons of forage dry matter (DM) per annum which constitutes about 12% of the total DM available from all feed resources of the country. • The carrying capacity of these rangelands is generally very low as they are mostly composed of natural grasses having poor nutritive value. • On DM basis, the average crude protein value of most of the natural grasses grown in Pakistan ranges from 5 to 8% only. Forage Production from Various Rangelands of Pakistan S. # Name of Rangelands Location Area (m.h) Forage Production (m to of DM) 01 Alpine Pastures Areas above altitude of 3000m and below the zone of perpetual snow 1.68 2.52 02 Traw-Himalayan Grazing Lands Northern mountains of Dir, Chitral, Gilgit, Chilas, Skardu and Swat Distt. 3.5 2.70 03 Himalayan Forests Siran, Kaghan, Neelam and Jhalum valleys 0.67 0.40 04 Pathwar Scrub Ranges RI/Islamabad, Chakwal, Jhalum, and Attock Distts. 1.68 2.52
  • 44. 44 05 Desert Rangelands Salt range, Indus and Chenab rivers flood plains 7.97 3.98 06 Kohistan Ranges Karachi, Thatta, Dadu and parts of Lasbella Distts 2.38 0.95 07 Central Balochistan Ranges Queta and Kalat divisions 8.00 4.00 08 Eastern Balochistan ranges Zhob and Loralai divisions 5.00 2.00 09 Western Balochistan Ranges Distts. Of Chagi, Kharan, Panjgur, Makran, Turbat, Gwader and Lasbella 18.5 5.55 10 Suleiman Mountain Ranges Elongated area along Afghanistan border 1.5 0.45 Important range grasses of Pakistan Some of the grasses commonly forced are various rangelands include: Dhamman, Bermuda, Blue panic, Palwan, Crested wheat, Mungha Rhodes Grass. Dhamman: Dhamman is a summer-growing perennial grass. Its quality varies with the stage of growth, is highly palatable. Bermuda: Bermuda grass undergoes active growth during spring and summer. Its leaves are very palatable and contain as much as 14% protein. It can with stand prolonged droughts and remains dormant during winter. Blue panic: The blue panic is a perennial grass having maximum growth during spring and summer. It derives its name from the bluish green color of its leaves. Palwan: Palwan is a perennial, drought tolerant and good soil binder. Crested wheat: Crested wheat grass is a perennial, tufted bunch grass. It can withstand very low temperatures and high grazing pressure.
  • 45. 45 Mungha: Murgeh grass is well snited to fertile loamy soil, when it can be established trhough seeds. It is palatable and nutrition’s and contains about 10% CP. Rhodes Grass: Rhodes grass is a summer-growing perennial grass. It is palatable, withstands grazing and soil binder. Important Range Grasses of Pakistan Common Name Technical Name Area/Rangeland where Grow Digestible DM yield (ton/hec) Dhaman grass Cenchrus ciliaris Desert rangelands, part of Pothwar and Balochistan range. 3-4 Bermuda grass Cynodon dactylon Desert rangelands, Pothwar ranges and parts of Kohistan ranges 3-4 Blue Panic grass Ponicum antidotale Pothwar scrud rangelands, Kohistan ranges and salt range 5-9 Palwan grass Bothriochloa pertusa Pothwar plateau and Himalayan forest ranges 4.8 Crested wheat grass Agropyron cristatum Areas with rainfall lower than 50 mm/year 3.4 Murgha grass Dichanthium annulatum Murree foothills, Pothwar plateau and D.I. Khan 6.8 Rhodes grass Chloris gayana Pothwar scrub ranges 7-8 Diet Formulation
  • 46. 46 The objectives in diet formulation are to design diets to meet the animal’s nutrient requirements and provide the maximum or optimum economic returned to the livestock producer. In general people like to feed their animals adequately at a reasonable cost. Information needed to formulate diets The following information is required for the efficient formulation f diet: 1. Nutritional requirements of the animals 2. Nutrient composition of the available feedstuffs. 3. Nutrient bioavailability. 4. Non-nutritive characteristics of the feedstuffs such as palatability, pelleting properties and associative effects. 5. Cost of available feedstuffs. 2. Nutritional Requirements • Standard sources in the USA for nutrient requirements of livestock are the NRC publications in the series Nutrient Requirements of Domestic Animals. • These publications contain tables of nutrient requirements for animals of various productive functions (growth, gestation, reproduction, etc.). • The requirements are expressed as per unit of diet (%, mg/kg, etc.) or as amount per anima per day. • These figures are the minimum requirements for maximum production and do not include a margin of safety. • Environmental condition, stress, housing conditions, breed or strain, disease incidence, and projected length and condition of feed storage are factors that might influence selection of an appropriate margin of safety. • A well formulated diet is one that meets NARC requirements and will support maximum animal performance. 3. Nutrient Composition of Feed Stuffs: Extension tables of competition of feedstuffs are available. However, feedstuffs are inherently variable products their composition in greatly influenced by Harvesting conditions, Environmental factors, Fertilization And irrigation practices, and so on.
  • 47. 47 Thus considerable judgment is needed in assessing whether any apparent defecating of a particular nutrient in truly important. 4. Nutrient Availability: • For most feedstuffs, the nutrients are not completely released during digestion. This is particularly true for energy fraction. • For this reason, digestible energy, metabolizable energy, or not energy values should be used rather than gross energy. • These values very between animal species, especially for fibrous feeds. • For poultry, ME values, and for ruminates ME or NE values should be used for ration formulation. Associative Effect: • It refers to the interaction between feedstuffs that can influence their nutrition value. • They may be +ve of –ve. • The DE content of forage, for instance, may be less if the forage is fed along with a concentrate than if fed alone. • Thus there may be negative association affect between fibrous feed sand concentrates in ruminates. • A +ve associative effect is the improvement in utilization of low-quality roughages when it is supplemented with alfalfa. Costs of available feedstuffs: • Costs of ingredients vary according to a number of factors. • The ingredients in largest supply will often dictate prices for other ingredients. • For example, the plant protein market in North America is dominated by soybean meal. The cost of SBM is influenced by crop yields, which in turn are influenced by acreage planted, weather conditions, and so forth; and by supplies available on the world market. • The costs of other protein sources, such as cottonseed and canola meal will be pegged to the price of SBM. Without knowing the prices of different available feed ingredients, economical feed formulation is not possible.
  • 48. 48 Feeding Standards: • These are tables listing the amounts of one or more nutrients required by different species of animals for specific production functions, such as growth, fattening, and lactation. • They are necessary guides in balancing rations. • Most feeding standards are expressed in either 1. Quantities of nutrients required per day, which Is used where animals are provided a given amount of a feed during a 24-hour period, Or 2. Concentration in the ration; which Is used where animals are provided a ration without limitation on the time in which it is consumed. • It USA, the NRC feeding standards, • And in England ARC for standards are mostly used. • In the USA, TDN system is gradually giving way to net energy system, • While England uses ME, system. • Other European standards are based on starch equivalents, Scandinavian feed units, and other methods. • The NRC has established feeding standards for beef cattle, dairy cattle, sheep, swim, poultry, horses, rabbits, minks and foxes, forest, salmon, catfish, and dogs. Balanced Ration: Is one which provides an animal the proper proportions and amounts of all the required nutrients for a period of 24 hours? In ration formulation feeds are initially divided into three categories: 1. Concentrates 2. Roughages and 3. Supplements. Ration formulation consists of combining feeds that will be eaten in the amount needed to supply the daily nutrient requirements of the animals. Formulating rations is both an art and a science-the art comes from animal know-how, experience, and been observation; the science is largely funded on mathematics, chemistry, physiology, bacteriology. Both are essential for success. Before attempting to balance a ration, the following major points should be considered: a). Availability and cost of feed ingredients; b). Moisture content
  • 49. 49 c). Composition of feeds under consideration d). Quality of feed 1. Stage of harvesting 2. Freedom from contamination 3. Uniformity 4. Length of storage e). Degree of processing f). Soil analysis g). The nutrient requirements and allowances In addition to providing a proper quantity of feed and to meeting the nutrition requirements, a well-balanced and satisfactory ration should be: a). Palatable and digestible b). Economical • The ideal ration is one that will maximize production at the lowest cost. • The cost per unit of production is the ultimate determinant of what constitutes the best ration. • Following four steps should be taken in an orderly fashion in order to formulate an economical ration. 1. Find and list the nutrient equipments and/or allowances for specific animal to be fed. 2. Determine what feeds are available and list their respective nutrient composition. 3. Determine the cost of feed ingredients under consideration 4. Consider the limitations of the various feed ingredients and formulate the most economical ration.