Ruminal microbial yields: factors influencing synthesis and bypass.

Bacterial growth (protein production) in the rumen is typically limited by anaerobic energy supply. But the mass of bacteria produced per mole of ATP (YATP) varies markedly with turnover or growth rate of bacteria, availability of cell components, accumulation of ash or starch, and intraspecies transfer of reducing equivalents. Increased turnover rate of rumen contents appears to enhance bacterial protein production, increase ruminal acetate and methane production and increase bypass of fiber and concentrate components of the ration.