ABSTRACT
The need for protein in animal diets has been well-known for a long time. Protein need and satisfying this need is a major topic among scientists and producers at nutrition meetings. Ruminants have a distinct advantage over monogastric animals, such as pigs and poultry, in that they can utilize nonprotein nitrogen for protein purposes. Bypass protein has received considerable attention. This is true protein that is not metabolized by the microorganisms in the rumen and therefore is digested further down in the gastrointestinal tract, thus "bypassing" the rumen. Theory states that high-producing cattle with a high protein need cannot obtain sufficient protein from rumen microbial metabolism; therefore they benefit if some of the protein bypasses the rumen without microbial breakdown. Cattle protein needs have been reviewed and protein recommendations have been made that consider weight, rate of gain, and proportion of roughage and concentrate in the diet. Protein requirements for feedlot bulls appear to be similar to steers.
