Protein Supplements in Animal Feed
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A blood meal is dried blood from animal processing plants. Spray or ring-dried blood meal is superior to batch dried because less heat damage occurs. A blood meal is high in true protein, UIP and the amino acid lysine. Limit the amounts fed to less than half (½) kg per cow per day, and do not feed in diets high in moisture, as palatability can become a problem.
Brewer’s grain, a by-product of the beer industry, is available dry or wet. Wet brewers’ grains contain 70 to 80% water. Feeding more than 20% of the ration DM or 18 to 23 kgs of wet feed per cow reduces intake and milk production. On a DM basis, brewers’ grains are high in protein and a fair source of energy.
Cottonseed meal is a high protein by-product from oil extraction from whole cottonseed. It is quite palatable but may be variable in CP content. Cottonseed meal and other products can contain a toxic substance known as gossypol. Limit the total amount of cottonseed products in diets to 3.8 kgs per cow per day or less.
Fishmeal is a by-product of the fish industry. It includes bones, head, trimmings, and fish parts. Quality can vary, depending on the source and handling. Fish oil reduces fibre digestion in the rumen and should be limited to 50 grams daily. Limit fish meals to 0.5 to 1 kg per day.
Linseed meal is a product of the flax industry and is a good protein supplement (39%). It is very palatable and can be used as a replacement for soybean meal.
Malt sprouts consist of dried sprouts and rootlets produced during the malting (sprouting) of barley for beer. The feed is similar to dried brewers grain, especially in UIP, but bitter tasting, reducing palatability. Limit amounts in the diet to less than 2.3 kgs per cow per day or 20% of the grain mix.
Meat and bone meal is a rendered and dried product from animal tissue. It does not contain horns, hide, hair, manure, or stomach contents. Meat and bone meal is a good source of CP, UIP, calcium and phosphorus. Limit amounts fed to 1 kg or less per day. Meat and bone meal need to be handled properly and stored in dry places to avoid salmonella contamination.
Soya beans are an excellent source of CP and fat (18%) for dairy cattle. Raw soybeans can be fed up to 2.3 kgs per cow per day. Cows should be adjusted to beans gradually to avoid diarrhoea and off-feed. Raw beans contain urease, an enzyme that releases ammonia from urea when soybeans and urea are mixed together. Urea and raw beans should not be mixed and stored together. Microbial degradation in the rumen reduces anti-protein factors in raw beans (trypsin inhibitor, for example). Roasting, extruding, or other heat processing reduces anti-protein factors and urea activity and increases the UIP value of the soybeans. Heating temperature (143 to 148 degrees C) and steeping time (30 to 45 minutes) must be carefully controlled to avoid under or overheating soybeans. Heat-treated soybeans can be fed up to 8 pounds per day. The cost of processing, including bean shrinkage, should be evaluated.
Soya bean meal is the most common and usually the most economical vegetable protein supplement. The most common soybean meal contains 44% CP as fed. Two other sources of soybean meal are: dehulled Soya bean meal (48% CP), and expeller or old processed soybean meal (42% CP and 5% fat). Many commercial supplements contain substantial amounts of soybean meal.
Sunflower meal protein supplements range from 28 to 45% protein. The protein percentage varies inversely with fibre percentage: lower protein, higher fibre. Sunflower meal is a good source of protein and phosphorus. Palatability problems have been observed in some herds when sunflower meal is top-dressed.
Urea is a NPN compound containing about 46% N. It is a good source of SIP. Urea fits best in diets high in carbohydrate energy (grains and maize silage), low in protein, and low in SIP. Limit amounts fed to 180 grams per cow per day, 1% in grain mixes, or 0.5% in maize silage (10 kg/ton added at ensiling). If urea or another NPN source like ammonia is added to maize silage, the amount of urea included in a grain mix should be reduced so that the intake of urea or urea equivalency does not exceed the maximum of 180 grams per cow per day. Urea is not a palatable feed and should be mixed thoroughly into the grain mix or silage. Urea is best utilized when incorporated into total mixed rations (TMR) and/or fed frequently in mixtures with other feeds.
Urea can be used in making up a high-protein concentrate. A mixture of 40 kg of ground-shelled maize and 6 kg of urea is equivalent in energy and crude protein to 45 kg of soya bean meal. A mixture of 25 kg of ground-shelled maize, 3 kg of urea, and 16 kg of soya bean meal also equals 45 kg of soybean meal in total energy and protein equivalent and can be used as a substitute for soya bean meal. However, it should not be used as a protein top dress because of its bitter taste and possible feed refusal. When fed according to recommendations, urea is a good crude protein (CP) source and has not been shown to affect reproduction efficiency.
Find more information in the Books of the Author: Success in Agribusiness
Farm Animal (Cattle) Nutrition
Feeding Systems of Farm Animals
Protein Supplements in Animal Feed
Livestock Feed selection – Evaluation of Feed Ingredients
Management of an intensive (Zero) Grazing System
Trace Minerals: The key to Immunity for Farm Animals
Dairy Cow Nutrition on different Lactation Cycles
Training Livestock Farmers for Sustainability and Food Security
