This study evaluated the effects of the inclusion of a yeast culture (Saccharomyces cerevisiae 1026) on the parameters of ruminal fermentation of beef cattle. Ten rumen fistulated 1/2 Red Angus 1/2 Nellore steers confined in individual pens were fed a diet containing 50% sorghum silage and 50% concentrate (%DM) containing peleted soybean hulls, sorghum grain, urea and mineralproteic premix. A completely randomized design was used to compare diets with or without Saccharomyces cerevisiae (1 g/100 kg of live weight) on two of the four daily meal. Ruminal pH, ruminal concentrations of ammoniacal nitrogen (N-NH3), acetate, propionate, butyrate, total volatile fatty acid (VFA) and acetate:propionate ratio values were not influenced by the supplementation of yeast culture. There were interaction between sampling time and treatments for pH, and molar concentrations of acetate and propionate. Ruminal pH, ruminal concentrations of acetate, propionate, total VFA and acetate:propionate ratio showed a quadratic response related to collection time. In diets with 50:50 forage to concentrate ratio, the supplementation of yeast culture did not influence the ruminal fermentative parameters.
ammoniacal nitrogen; pH; steers; volatile fatty acid
