Classifications of Feeds
All feeds can be classified into specific categories based on their primary function in the diet, whether the feed is a protein or energy feed, for example. A basic understanding of the classification of feed and the nutrient content of common feeds will make it easier for producers to make feeding decisions.
Feeds fall into two main groups: roughage/forage or concentrates. Feeds can be further sub-classified as shown in Figure 1.
A wide variety of forages, grains, oilseeds, by-products, and crop residues can be used to feed cattle. Some of the more common feeds are described briefly in the following paragraphs. Table 4 lists the nutrient content of some feeds common to Virginia. Feed values are normally listed on a dry matter (DM) basis because dry matter contains all of the important nutrients. This is the nutrient content of the feed if all water was removed. This makes it easy to compare feeds and evaluate their nutrient composition. For example, a feed with 90% DM is a dry feed in its everyday form (i.e. corn), whereas a 35% DM feed is a wet feed as it is normally fed (i.e. silage). It would be difficult to compare these two feeds unless we look at the nutrient content on a DM basis.