Function of rumen Bacteria ,IN THE RUMEN.
Microbes in the rumen require protein (nitrogen) and energy to grow and multiply. In order to acquire nitrogen for growth, these microbes break down feed protein into both amino acids and non-protein nitrogen compounds such as ammonia. Microbes derive energy from the carbohydrates (sugars, starches, cellulose and hemicellulose) found in grains and forages. Microbes pass out of the rumen and are digested in the small intestine providing 40 to 80% of the ruminant’s requirement for metabolize protein, depending on stage of growth or lactation.

Rumen microbes grow best when the supply of energy and nitrogen is in synchrony. Slowly digesting carbohydrates such as cellulose are most compatible with protein sources having slow rates of degradation (breakdown) that provide a steady supply of nitrogen. Frequent meals also help to provide a steady supply of nitrogen for the microbes.

The proteins in corn silage and other forages contain both degradable and undegradable fractions (Fig. 2). The overall degradability of protein in the rumen is determined by two factors: the portion of protein that is digested by microbes in the rumen and the speed of digestion in the rumen relative to rate of passage out of the rumen. If the rate of passage out of the rumen is high (high feed intake), then the microbes will not have a chance to degrade the feed protein. Hence, rumen protein degradability will be decreased. The degradable protein fraction can be subdivided into those proteins that degrade rapidly and those that degrade over a longer period of time.