Animal feeds are classified as follows: (1) concentrates, high in energy value, including fat, cereal grains and their by-products (barley, corn, oats, rye, wheat), high-protein oil meals or cakes (soybean, canola, cottonseedpeanut [groundnut]), and by-products from processing of sugar beets, sugarcane, animals, and fish, and (2) roughages, including pasture grasses, hays, silage, root crops, straw, and stover (cornstalks).Concentrate food

Cereal grains and their by-products

In the agricultural practices of North America and northern Europe, barley, corn, oatsrye, and sorghums are grown almost entirely as animal feed, although small quantities are processed for human consumption as well. These grains are fed whole or ground, either singly or mixed with high-protein oil meals or other by-products, minerals, and vitamins to form a complete feed for pigs and poultry or an adequate dietary supplement for ruminants and horses.

The production of grains is seasonal because of temperature or moisture conditions or a combination of both. It is necessary to produce a full year’s supply during the limited growing season. The grain is dried to 14 percent or less moisture to prevent sprouting or molding; the grain is then stored in containers or buildings where insects and rodents cannot destroy it. It is generally desirable to store more than a year’s supply of the grains to be used as feed, because crop failures sometimes occur.

High-protein meals

Vegetable seeds produced primarily as a source of oil for human food and industrial uses include soybeanspeanuts (groundnuts), flaxseed (linseed), canola, cottonseedcoconutsoil palm, and sunflower seeds. After these seeds are processed to remove the oil, the residues, which may contain from 5 percent to less than 1 percent of fat and 20 to 50 percent of protein, are marketed as animal feeds. Cottonseed and peanuts have woody hulls or shells, which are generally removed before processing—if the hulls or shells are left intact, the resulting by-product is higher in fibre and appreciably lower in protein and energy value. The protein quality of these meals for monogastrics varies greatly depending on the levels and availability of the amino acids present. Ruminants in general require only protein or nitrogen sources for the rumen microbes to synthesize amino acids.

These high-protein feeds supplement inexpensive roughages, cereal grains, and other low-protein feeds in order to furnish the protein and amino acids needed for efficient growth or production. The supplement chosen for a particular diet depends largely on the cost and availability of supply.