CASE STUDY: Effect of Supplemental Live Yeast on Yield of Milk and Milk Components in High-Producing Multiparous Holstein Cows

ABSTRACT A well-managed, high-producing commercial dairy herd was used to test the effect of supplementing live yeast (4 g/d per cow) to lactating Holstein cow diets. When data from cows on study for > 4 wk were analyzed separately, milk yield was greater (P   4 wk produced more (P   0.10) on 3.5% FCM yield, milk fat percentage, yield of milk fat, or milk true protein percentage over the entire test period. Overall milk true protein yield tended (P = 0.11) to be higher with the addition of live yeast to the diet. Milk urea nitrogen (mg/dL) and SCC were not affected (P > 0.10) by treatment. Cows supplemented with live yeast produced milk with a higher percentage of lactose and solids-not-fat (P