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Types of Proteins Used in Animal Feed

Types of Proteins Used in Animal Feed

Animal Feed is an important factor in the nutrition of animals and keeps up with the growing global demand for meat, dairy products, wool etc. Modern feed is developed by carefully selecting and combining ingredients to provide highly nutritious diets that both sustain animal health and improve the quality of end products.

Protein in Animal Feeds

Protein is also required for immature animals to build the muscles and other parts of the body. Since milk, eggs, and wool contain plenty of protein, additional amounts are required in the animal feed that produces these. For care, all animals need a small amount of protein — that is, the regular repair of muscles, internal organs, and other body tissues.

Proteins are made up of over 20 different amino acids that are released during digestion. Animals with a basic (monogastric) single stomach, like humans, chickens, rabbits, and mink, require sufficient quantities of the following 10 essential amino acids every day: arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. Besides these, for growth, the poultry requires glycine and glutamic acid. Cystine can replace up to half the requirement for methionine, and tyrosine can replace up to half the requirement for phenylalanine.

Buy High-Quality Feed Protein

High-quality protein, such as that given by eggs, milk, fish meal, meat by-products, and soybean meal, provides high concentrations of the essential amino acids in the required balance for their maximum use. Poor-quality protein, such as that which contains too little of one or more important amino acids in most grains, including corn, barley, and sorghum. Feeds with poor proteins are useful when mixed with other feeds that restore balance in essential amino acids.

The amino acid profile of a protein source is of secondary importance for ruminants, such as cattle, sheep, goats, and other animals with four stomachs, since the bacteria that help digest food in the rumen (first stomach) use simple nitrogen compounds to create proteins in their cells. Further, the animals eat the bacteria in the digestive tract. By this indirect means, ruminants produce high-quality protein from food that may have originally produced weak protein or urea (a compound of nitrogen). However, very young ruminants, such as calves, lambs, and infants, need high-quality protein before the rumen develops enough to build itself for this bacterial process

Science, observation, and chemical analysis by agricultural scientists have contributed to ongoing changes in animal diets.

Animal feeds can essentially be divided into two types.

  1. Concentrates
  2. Roughages

 Let’s dig in deep about each type and learn in detail about the proteins and other minerals involved in each type of feed, starting with;

–  Concentrates

It has high energy value, and high-protein oil meals including soybean, canola, cottonseed, peanuts, and the by-products from the processing of sugar beets, sugarcane, animals, and fish. It also includes cereal grains and their by-products like barley, corn, oats, rye, and wheat.

Proteins provided through Cereal grains and their by-products

Barley, corn, oats, rye, and sorghum are cultivated almost exclusively as animal feed in the agricultural practices of North America and Northern Europe, though limited amounts are often processed for human consumption. These grains are fed whole or ground to form a complete feed for pigs and poultry or an appropriate dietary supplement for ruminants and horses, either individually or combined with high-protein oil meals or other by-products, minerals, and vitamins.

Meals with High-Proteins

Vegetable seeds mainly produced as a source of oil for human food and industrial use include soybeans, peanuts (groundnuts), linseed, canola, cotton seeds, coconuts, oil palms, and sunflower seeds. The residues, which can contain from 5% to less than 1% of fat and 20 to 50% of protein, are sold as animal feeds after these seeds are processed to extract the oil. 

Cotton and peanuts have woody hulls or shells that are normally discarded before processing — if the hulls or shells remain intact, the resulting by-product is higher in fibre and slightly lower in the value of protein and oil. For monogastric the protein content of these meals varies greatly depending on the amounts and availability of the present amino acids. Ruminants typically require only the sources of protein or nitrogen to synthesize amino acids for the rumen microbes.

Sugarcane and Sugar-beets by-products

Beet tops, which are either fresh or ensiled on the field, and dried beet pulp and beet molasses which are processed in sugar factories, come from the sugar beet industry. Cane molasses are residues from the manufacture of cane sugar.


All these are palatable, high-quality carbohydrate sources. Sugarcane bagasse (stalk residue) is fibrous, difficult to digest, and very poor in the feed. Beets and some other roots are used in Europe as animal feed.

As by-products of the citrus juice industry, citrus molasses and dried citrus pulp, which are typically available at low cost, are also used as high-quality feeds for cattle and sheep.

Other Feeds Extracted from by-products

Huge amounts of animal feed are by-products or residues produced from commercial cereal grain processing for human consumption. These by-product feeds are the largest category from wheat milling, including wheat bran, wheat middlings, wheat germ meal, and wheat mill feed. Bakery waste, such as old and discarded bread, rolls, and other pastry items, is ground in some areas and is used as filler or feed for pets and farm animals.

Rice bran and rice hulls are obtained from the mills which polish rice for human food in a similar fashion. Corn gluten feed, corn gluten meal, and hominy feed are processed as by-products of starch processing for industrial and food usage.

Brewers ‘grains, grains and solubles from corn distillers, and brewer’s yeast are useful animal feeds and are obtained from the fermentation industries’ dried residues that produce beer and distilled spirits. Waste products from plants for pineapple-canning include pineapple bran or pulp, and plant ensiled leaves.

Slaughterhouse by-products and meatpacking plants turning animals into meat include feeds such as beef and bonemeal, tankage (left animal residue after slaughterhouse fat), beef scraps, blood meal, poultry waste, and feather meal. Fish-processing plants produce different types and quality of fish meals.

Usually, these animal by-products contain 50% or more high-quality protein and calcium and phosphorus mineral components. In these essential minerals, the steamed bonemeal is especially strong. Dry skim milk, dried whey, and dried buttermilk are dairy industry feed by-products.


Rice Protein

Rice protein is an isolate of vegan protein which is an alternative to the more common isolates of whey and soy protein. Brown rice can be handled with enzymes that separate the carbohydrates from proteins. The resulting protein powder is then flavoured or occasionally added to smoothies or wellness shakes.

Rice protein powder has a more distinctive flavour than most other protein powder types. Like whey hydrolysate, most flavours do not disguise this flavour effectively; however, rice protein taste is generally considered less objectionable than whey hydrolysate’s bitter taste. Consumers of rice protein may also prefer this special rice protein flavour to artificial flavourings.

Rice protein is most often combined with powdered pea protein. Rice protein is high in the amino acids, cysteine, and methionine that contain sulfur, but low in lysine. In comparison, pea protein is low in cysteine and methionine but high in lysine. The combination of rice and pea protein thus provides a superior amino acid profile comparable to dairy or egg protein but without the potential for allergies or intestinal problems that some consumers have with these proteins. Also, pea protein’s light, fluffy texture tends to smooth out the solid, chalky aroma of rice protein.

Different variations and combinations of rice protein are also used in animal feeds. Rice protein is usually mixed with feeds with low concentrations of protein.

–  Roughages

Roughages include hays, silage, pasture grasses, root crops, straw, and stover.


The most important single source of feed for ruminants such as cattle, horses, sheep, and goats is pasture grasses and legumes, both natural and cultivated. They supply most of the feed for these animals at a lower cost during the growing season than for feeds that need to be collected, processed, and transported.

Hundreds of different plants, legumes, bushes, and trees are suitable for grazing animals as feed. The nutritional value of the cultivated varieties has been studied but for many of those that occur naturally, knowledge is incomplete.


Hay is produced by drying grasses or legumes upon reaching the stage of maximum plant growth and before the seed develops. It has been shown that this stage gives the maximum yield of digestible protein and carbohydrates per unit of land area. To avoid moulding, heating, and spoilage during storage, the moisture content is usually decreased below 18%.

Legume hays, such as alfalfa and clovers, are high in protein, while the grasses (such as Timothy and Sudanese grass) are lower in protein and differ considerably depending on their maturity stage and the amount of nitrogen fertilization applied. Stored hay is fed to livestock when there is not enough fresh grass suitable for pasture.

Root Crops

For economic purposes, the root crops are used less widely as animal feed than was the case in the past. It uses beets (deficiencies), rutabagas, cassava, turnips, and occasionally surplus potatoes as feed. Root crops are poor in dry matter content and protein compared with other feeds; they produce more energy.

Straw and Hulls

Quantities of straw that remain after the wheat, oats, barley, and rice crops are harvested are used as feed for cattle and other ruminants. The straws are low in protein and very high in fibre; they have poor digestibility.

Straw is useful in maintaining mature animals when other feeds are in short supply, but it is too low in nutrition to be a satisfactory feed for extended periods unless supplemented with other feeds to provide the protein, digestible energy, and minerals required for growth and development.

Treatment of straw with alkali greatly improves the cellulose’s digestibility, raising its importance as an energy source for animals. 


Protein is an essential part of animal feed and above we explored how and which protein is an integral part of different types of animal feeds. We discussed and learned about multiple sources of animal feed.

If you are looking for protein to add to animal feed, then check our range of proteins developed especially for feed.


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