acidosis, lactate, Megasphaera, diet transition


Direct-fed microbials commonly have been used to enhance performance or to decrease shedding of foodborne pathogens in beef cattle. Megasphaera elsdenii is a recently introduced probiotic bacteria marketed under the trade name Lactipro (MS-Biotec Inc., Wamego, KS) and is a key lactate-fermenting bacterium in the rumens of cattle fed high-concentrate diets. Megasphaera elsdenii is responsible for metabolizing up to 95% lactic acid within the rumen, and thus is an important species for controlling occurrence of ruminal acidosis. The objective of this study was to evaluate changes in ruminal pH and volatile fatty acid concentration during the transition from a diet with 60% concentrate to a diet containing 80% concentrate after administering five different oral dosages of Lactipro.