Feeding yeast culture fermentation products has been associated with improved feed intake and milk yield in transition dairy cows. The objective of this study was to evaluate the effects of a commercial yeast culture product (Cellerate Culture Classic HD (YC); Phibro Animal Health, Teaneck, NJ) on performance, blood biomarkers, and rumen fermentation and bacterial population in dairy cows during the transition period until 50 DIM. Forty Holstein dairy cows were enrolled in a randomized complete block design from− 30 to 50 DIM and
