Title: Yeast Culture Improves Lactation Performance and Metabolic Status in Transition Dairy Cows

Yeast culture supplementation has been used to improve the health and performance of dairy cows for the last 25 years. To evaluate the effect of a Saccharomyces cerevisiae fermentation product (Diamond V Original XP™) on the health and production of peripartal Holstein cows, two research studies were conducted. The first experiment took place on the Oregon State University research dairy where feed intake behavior was continuously monitored. Treatments (administered 3 wks before anticipated calving date through 3 wks postpartum) included 0, 57, and 228 g/d XP. Yeast culture was reported to affect primi- and multiparous cows similarly by improving milk yield and prepartum intake, with little effect on metabolic parameters. To test the effect on a larger scale, a second experiment was conducted using 96 multiparous cows on a commercial dairy. A method for individually feeding cows in a freestall barn was created and implemented to preserve the cow as the experimental unit. Cows were given treatments (0, 56, or 112 g/d XP) daily from 4 wks prior to expected calving date through 4 wks postpartum. Yeast culture supplementation significantly improved lactation performance in second parity cows and improved metabolic status of all cows, especially older animals