ABSTRACT

This chapter addresses alternative methods for determining protein needs of ruminants. The standard method for calculating ruminant protein needs has been to chemically measure the nitrogen associated with the function of interest and to calculate crude protein by a conversion factor. The ruminants' protein needs are similar to those of other animals, except for the action of the rumen. However, the fermentation activity in the rumen is so extensive that the major research efforts have concentrated on investigations of the rumen. Primary questions have concerned: the amount and rate of bacterial degradation of feed protein to ammonia in the rumen, the ability of the microbial population in the rumen to produce protein from the ammonia produced from degradation of feed and urea in saliva and from blood, and the amount of total protein that flows from the rumen in all forms and is available to the animal.