EFFECT OF YEAST CULTURE (SACCHAROMYCES-CEREVISIAE) ON ADAPTATION OF COWS TO DIETS POSTPARTUM

For approximately 14 d prepartum and exactly 14 d postpartum, 20 multi parous Holstein cows were fed different basal diets that were suppleme nted, or not supplemented, with a yeast culture preparation. Cows supp lemented with yeast culture lost less body condition prepartum, which was consistent with numerically higher body weight gain. No treatment differences were found in prepartum or postpartum dry matter intakes ( DMI) or components of DMI. In addition, the extent of the depression i n DMI prepartum and the rate of increase in DMI postpartum were not in fluenced by yeast culture supplementation. Milk and milk component yie lds were not influenced by yeast culture supplementation. Cows in both groups had higher calculated net energy for lactation for the diets p ostpartum than would have been expected based on values of the Nationa l Research Council for feedstuffs. The increased net energy for lactat ion seemed to be related to higher than expected metabolic efficiency during early lactation. Results of both the prepartum and postpartum p eriods were consistent with the hypothesis that supplementation of yea st culture in the diet increased net digestion in the forestomach, par ticularly of fiber, leading to increased energy output. However, there was no evidence to suggest that supplementation of yeast culture prep artum alleviated the reduction in DMI prepartum or improved the rate o f increase in DMI postpartum.