Use of Low Quality Crop Residues

Low quality fibrous crop residues include

Straws, Sugarcane bagasse, Hulls, Corn cake

These are very low in digestible energy and protein But these are highly lignified.

In Rumen

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: 2. Physical Treatment

1: Chemical Treatment:

Lignification’s 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 (cover) 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.

Disadvantages:

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.

Ammoniation

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.

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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.

UreaUrea can be used as a some of ammonia, and most roughage have sufficient bacterial urease present to convert urea to ammonia.

Ammoniation reduces effects of aflatoxin. It also reduces glucosinolates in mustard meal.

Toxicity of Ammoniated Roughages:

Ammoniation of feeds may produce toxins and toxicity symptoms in animals consuming such treated feed.

Name of the Toxicity:

This toxicity has been named as

Bovine hysteine, Bovine bonkers, Ammoniated hay toxicosis, Hyper excitability, Crazy cow syndrome

Signs of the Toxicity:

Neurological signs, such as Hyperactivity, Incardination, Tremors Convulsions occur in affected animals.

Cattle may become extremely nervous and difficult to handle. Affected animals may suddenly gallop (Race) in circles and run into fences (Screen), gates, and other objects, often causing them 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 70C during ammoniation.

Ammoniation of molasses may also produce bovine hysteine. Because of the involvement of reducing sugars, ammoniation of good quality roughages with abundant reserves of carbohydrate should be avoided.

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Other Chemical Treatment:

Treatment with Alkaline hydrogen peroxide solutionTreatment 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 with OzoneTreatment of roughages with ozone has also been shown to degrade lignin and improve fiber digestibility.

2. 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 microbe’s 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.

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Feed additives and their use in livestock feeding

Feed additive is an ingredient or combination of ingredients added to the basic feed mix to fulfill the specific used.

It may also be defined as any chemical incorporate in an animal feed for the purpose of improving rate of gain, feed efficiency, or preventing and controlling disease. A feed additive need not to be a drug.

Types of Feed Additives:

Feed additives can be a classified into 2 classes

1. Nutrient feed additives: e.g. Amino acid, minerals and vitamins

2. Non-nutrient feed additives: e.g.

1) Antibiotics, 2) hormones, 3) common modulators,

4) Coccidiostates, 5) enzymes, 6) probiotics,

7) Yeast acidifiers, 8) antioxidants, 9) mycotoxin binders,

10) Anti-caking agents, 11) feed preservatives, 12) Flavoring agents,

13) Coloring agents, 14) pellet binders, 15) dietary buffers,

16) Methane inhibitors, 17) propionate promoters, 18) defamation agents,

19) tranquilizers, 20) emulsifiers 21) stabilizers

22) Surfactants, 23) sweetening agents

25) Heptoses & bloat controlling agents

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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 favor the proliferation of antibiotic resistant microorganisms. Use of antibiotic in ruminants feed is not common in Pakistan.

Antimicrobial feed additives and 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.

1: Ionophores Antibiotics:

These are produced by several strains of streptomyces species e.g. Monensin, Lasalocid, Salinomycine, Hysocellin, which are antimicrobial compounds.

Monensin 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 production3. Depress the activity of some rumen enzymes like proteases, deaminases, and urease.4. Decrease the passage rate of feed; thus increasing the ME value per unit of feed intake.

(10%). 5. Both monensin and lasalocid inhibit the growth of ruminal microbes which produce

acetate. Butyrate, lactate, Formate and hydrogen as major products.6. Other organisms which produce succnate and propionate or utilize lactic acid would grow

rapidly in the presence of ionophores. The production of increased levels of propionic acid in the rumen is related to improved animal performance. Propionate has protein

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spending effect and stimulates body protein synthesis and thus improves growth promoting activity.

Lasalocid (Trade Name: Bovatec):

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.

Antibiotics:

Benefits of growth promoting antibiotics in animal feeds include: better weight gain, higher feed conversion ratio and less meruse with lower N and P content.

Absorbable antibiotics Tetracycline, oxytetracycline and chlortetracycline

Non-absorbable antibiotics:Zinc bacitracin, avoparcin, monensin, virginiamycin, etc which have beneficial effects on the microflora of the intestinal tract.

As per the latest European Union (EU) regulation (followed for September 1999) only monensin, Salinomycin, flavomycin and avilamycin are the from feed grade pharmaceutical antibiotics remaining on the approved list.

Arsenicals: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 proportional 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.

2): Hormones:

The active principles secreted by the endocrine glands into the blood for transportation to target organs and tissues are known as hormone.

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The two broad types of hormones include:

1. Anabolic 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 subcutaneous fat intramuscular fat than steers. Anabolic agent’s enhance nitrogen retention in the body and particularly in the muscle, and result in production of leaser 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, trenbolone acetate (TBA),

Zeranol (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 sustention; increases skeletal growth and improves growth and milk production.

Exogenous Bovine Somatotropin (BST) injections:

A greater negative energy balance of often observed in cows during the first few weeks after beginning the administration of bST, but cows gradually increase their feed intake to obtain the required nutrients for body weight gain and increased milk production.

High yielding cows treated with daily s/c injections of b St (12-50g) gave

20 to 40% increase in milk yield and 12-14% increased feed efficiency.

The increase in milk yield were associated with increase sin feed intake.

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The availability of slow release 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 gain 12 to 15% higher milk yield over control animals.

Levels of ST in milk produced by treated cows are exceedingly low and constitute no threat to the human consumer.

In beef cattle steroid implants and somatotropin 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.

3: 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 beta-glucans

B-glucanases and xylanasesFeed enzymes such as B-glucanases and xylanases have enabled barley or wheat in poultry diets upto 50 or 50%.

Arabinases, xylanases and pectinasesArabinases, 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.

Celluloses, B-glucanases and protease and Phytase

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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“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.

4: Probiotics

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”.

Probiotics are advocated as an alternative to antibiotics for growth promotion. Probiotics are live cultures of non-pathogenic organisms which are administered 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

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

Bifidobacterium bifidum Aspergillus oryzae Torulopsis

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Streptococus faecuim S. thermophilus Saccharomyces cerevisiae

1. Lactobacillus acidophilus produce lactic acid and the enzyme amylase

2. Lactobacillus casei complements the growth of L. aciclophillus.

3. Bifidobacterium bifidum is commonly found in mother milk and the intestine of humans and animals.

4. Aspergillus oryzae produce enzyme cellulose.

5. Torulopsis is the mother culture of yeast. The enzyme lipase is exhibited by Torulopsis. Probiotics at the specific concentration stimulate immunity.

6. A low pH (4-5) favors lactobacillus sp.

7. And a high pH (6-7) is optimal for E. coli.

8. Shortly after hatching, the chick has a nearly sterile digestive tract with a pH range of 5.5 to 6.0.

9. 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.

Direct-fed microbial

These included

Lactobacillus, streptococcus, Bacillus yeast (Saccharomyces cerevisiae)

1. Lactobacilli are delicate microbes that are unable to withstand various environmental extremes, such as the heat and pressure of pelleting.

2. Bacilli are very stable microbes that can survive pelleting.

3. 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.

4. 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.

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5. 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.

5: Yeast Culture:

1. It is known to contain compounds formerly knows to as UFGs which positively affect animal performance. Rumen bacterial concentrations increase when fermentation products such as yeast cultures are added to the diet. 2. Metabolites in the fermentation products serve as nutrients for the bacteria.

3. Byproducts of fermentation include

Dried brewers yeast

Dried distillers soluble

Dried bacterial press cakes.

4. Yeast cells are destroyed by

Pelleting the feed,

Storage conditions

Strong mineral mixtures.

6. Significant losses of variable yeast cells canals occur over time for yeast products hold at 35oC in paper bags. The rate of deterioration is time and temperature dependant.

7. 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 acts by production of growth stimulating factors in the rumen. Stabilizing rumen pH and reduction of lactic acid production, and increasing rumen bacterial population.

8. 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.

9. 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.

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10. 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.

11. Acetate was reduced which propionate was increased by yeast addition.

12. Ruminal protozoa numbers increased in steers fed yeast culture.

13. Total and cellulytic bacteria were higher in ruminal fluid of calves fed yeast culture.

14. White rot fungi decompose lignin or lignocelluloses with minimal degradation of hemicelluloses and cellulose. Yeasts are always found in culture of white rot fungi.

15. The potential synergism between yeast (S. cerevisiae) and fungi (Armillaria heimii) had the best potential for increasing forage digestibility.

16. Inclusion of yeast culture diets given to yearling horses.

17. Supplementation of broilers diet with live yeast culture (1 kg/ton) may increase weight gain and FCR.

18. 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.

6: 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/ton2. Prop-ionic acid- 8-10kg/ton

Organic acids in powder form are:

1. Fumaric acid 12-15kg/ton2. Citric acid 20-25kg/ton.

In diets for laying hens, the feed additive calcium format (1.3%), which is converted to formic acid in the crop, offers potential benefits beyond reducing E. coli and salmonella populations.

It inhibits molds;

improves consistency of droppings, resulting in fewer dirty eggs;

better calcium absorption

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Better 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.

7: 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 limit 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

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(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.

8: 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.

9: Anti-caking 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.

10: 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.

11: Antifungal agents:

Sodium propionate, sodium benzoate, nystatin, etc.

12: 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 perceptions, aid in sedimentary salivary senction, help to regulate water intake and help to overcome stress. Hence

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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, and ginger are examples of spice and seasoning.

13: 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

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layers it improves shell quality and better litter conditions. During heat stress the dose is 3.6 to 4.5 kg/ton. Part of sodium bicarbonate can be given via water.

Methane 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

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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 Miscellaneous e.g. Ant metals and Ant vitamins

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.

Group-1

Protein

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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 better taste, farming in aqueous solution and heamolyse ABC. Generally saponins are less important because their levels are low in most common feed ingredients for monogastrics animals.

The important common forages which cause saponin poisoning of livestock are lucern, soybean, etc. average saponin 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 kingdom. It occurs mainly in the form of cyanogenic in plants the glucoside is non-toxic in the intact tissues. These glycosides can be hydrolyzed 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 cyanide can cause sudden death. Ruminants are more susceptible to HCN poisoning than horses. Cattle are most susceptible than sheep.

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It usually causes reduced growth; poor feed efficiency and result in death if consumed in increased amounts.

Clinical symptoms are characterized by

Mental confusion,

sudden peresis

Respiratory distress,

Abdominal pain

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 physical damage by frost, etc. heavy nitrate fertilization followed by an abundant irrigation or rainfall may increase the potential of HCN poisoning of these crops.

Feeding of immature jawar green fodder should be avoided to prevent HCN poisoning. 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 france. These are responsible for the pungent ferns found in plants belonging to the genus brassica. They mainly depress synthesis of thyroid hormone (thyroxine, 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 glucosinolate. High-or-low-glucosinolate 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 cavities, cardiac irregularity, reduced haemogblin content, etc. Decrease egg size and egg hatchability are also observed. Free gossypol content of 0.06% depresses growth in chicks, while 0.1% causes severe effects.

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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

(A) Hydrolysable tannins, which can be readily hydrolyzed by water, acids, bases or enzymes;

(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 Lucerne 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:

1. Physical:

Soaking 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 polyvinyl pyroldone (PVP) prevent formation of complexes between tannin and protein as well as break the already formed complex thus liberating protein. Alkalis, formaldehyde, organic solvents like acetone, acids, H2O2 reduce the tannin content.

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Susbania grandiflora has toxic substances such as saponins, tannins, amines, alkaloids, etc.

Group-IV1. Anti-metals:

These substances depressing minerals utilization

Phytic Acid:

About 67% or more of the phosphorus in cercal grains is in the form of Phytic 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 origin are usually available at the rate of more than 80%.Addition of the enzyme Phytase to the ingredients of vegetable origin can increase digestibility 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 ripening of vegetables is accompanied by an increase in the proportion of calcium oxalate.Growth and blood calcium is decreased in poultry. 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 hypocalcemia. Oxalate poisoning in livestock results principally from ingesting oxalate-producing plants which are very palatable to them.

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Oxalate poisoning in cattle and sheep are characterized by rapid and labored respiration, depression, weakness, coma and death.

2. Anti-vitamins:

These are organic compounds which either destroy certain vitamins or combine and form unbearable complexes or interfere with digestive and /or metabolic functions.

A). Anti-vitamin A:

Raw soybean contains enzyme lipoxygenase which can be destroyed by heating 5 minutes with steam at atmospheric pressure. Lipoxygenase catalyses oxidation of carotene, (the precursor of vit. A)

B). Anti-vitamin E.

Present in kidney beans can produce muscular dystrophy in chicks and lambs by reducing plasma vit. E. Autoclaving destroys it.

C). Anti-vitamin K:

Eating sweet clover cause fatal hemorrhage in cattleThis 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). Anti-vitamin D:

Unheated soy protein affects chicks and autoclaving eliminates it.

E). Anti-pyridoxine:

Found in linseed meal and affects chicks, this can be considerably improved after water treatment and autoclaving.

F). Anti-niacin:

An antagonist of niacin, niacytin is found in maize, wheat bran, etc. which causes perosis and growth depression.

Nitrate Poisoning:

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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. 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 deaths 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:

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In practice, this usually occurs only after a large amount 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 breathing, coordination, and death, occur when ammonia N is systemic blood has increased from normal concentration of less than 1mg’litre to more than about 7-12mg.litre.

Toxicity is most likely to occur when NPN some is given without other feed or with a poor energy source such as fiber.

Under these conditions toxic effects were seen in sheep and cattle given single doses of urea rouging from 0.3 to 0.8 g/kg body weight.

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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.

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Reaction is rapid at higher moisture level. Temperature below 15oC retard insect reproduction. Temperature between 21-43oC 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

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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 compoundsAflatoxin 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:

These have long been associated with occasional outbreaks of blind staggers in horses.

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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; sodium betonies, activated charcoal,

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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.

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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

LocationArea

(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

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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

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

RangesQueta and Kalat divisions

8.00 4.00

08 Eastern Balochistan

rangesZhob 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 PakistanSome 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:

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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.

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 NameArea/Rangeland where Grow Digestible

DM yield (ton/hec)

Dhaman grass Cenchrus ciliarisDesert 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 antidotalePothwar scrud rangelands,

Kohistan ranges and salt range

5-9

Palwan grass Bothriochloa pertusaPothwar plateau and Himalayan

forest ranges

4.8

Crested wheat grass Agropyron cristatumAreas with rainfall lower than 50

mm/year

3.4

Murgha grassDichanthium

annulatum

Murree foothills, Pothwar plateau

and D.I. Khan

6.8

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Rhodes grass Chloris gayana Pothwar scrub ranges 7-8

Diet Formulation

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.

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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.

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.

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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.

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:

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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. Concentrates2. Roughages and3. 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

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.

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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.

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