AFRC Technical Committee on responses to nutrients. Report No. 9. Nutritive requirements of ruminant animals: protein.

Abstract

This review considers protein requirements of ruminants and discusses systems which have previously been used to estimate requirements. The Working Party of the Agricultural and Food Research Council recommends that, since protein requirements should take account of the separate needs of rumen microbes and of the animal at tissue level, the digestible crude protein system should be abandoned and replaced by a metabolizable protein system, which describes the protein content of feeds in terms of rumen degradability of dietary protein, synthesis of microbial protein and digestibility of undegraded dietary protein.