Abstract: For studying the effects of saccharomyces cerevisiae culture on milk yield and milk composition of Holstein dairy cows in late lactation, 254 healthy Holstein cows with similar lactation days were randomly divided into two groups A and B. Group A was fed with 4% saccharomyces cerevisiae culture and group B was fed with basic high concentrate diet. The results showed that the descent rate of milk yield of the experimental group A with saccharomyces cerevisiae culture was significantly lower than that of the control group B. The milk yield of the experimental group decreased by 1.55% and control group decreased by 4.89%. In addition, the increase of milk protein and milk fat content in the experimental group was 3.19%, and 4.99%, respectively, which was higher than that in the control group（0.32% and 3.67%, respectively）. It suggested that adding saccharomyces cerevisiae culture to high-concentrate diet could improve feed conversion efficiency, indirectly increase milk production in late lactation stage, prolong lactation cycle, and significantly increase milk protein and milk fat content.

Key words: saccharomyces cerevisiae culture, late lactation, milk yield, milk composition, dairy cows