Protein is the source of amino aids and nitrogen in feeds.
It is needed by livestock for growth and milk production. Protein is also needed by rumen bacteria, which digest much of the feed for ruminant animals like cattle, sheep and goats. These classes are termed the soluble, degraded, and undegraded intake protein fractions. Some of this rapidly available protein is needed by the rumen bacteria when their growth rate is high. The DIP is used by the rumen bacteria for their growth and for digesting feeds in the rumen for the animals.