Dry matter intake and milk yield and composition of cows fed yeast prepartum and postpartum

Thirty-six multiparous and 12 primiparous Holstein cows were utilized in a completely randomized design to characterize the effects of feeding yeast cultures (Saccharomyces cerevisiae) and enzymes on dry matter intake and milk yield and composition. The prepartum diet consisted of a total mixed ration containing chopped grass hay, corn silage, and grain pellet. The postpartum diet consisted of a total mixed ration containing corn silage, legume silage, chopped legume hay, and grain pellet. Treatments consisted of 1) whey control, 10 g/d; 2) enzyme, 10 g/d; 3) yeast; 15 g/d; and 4) Biomate Yeast Plus^® (20 g/d; Chr. Hansen BioSystems, Inc., Milwaukee, WI). Treatments were top-dressed at feeding time. Cows were housed in a tie-stall barn, had continuous access to fresh water, and were fed once daily at 0800 h for ad libitum intake. Daily intake and orts were recorded beginning 28 d prior to the expected calving date through wk 13 of lactation. Daily milk yield and weekly milk samples were collected through wk 13 of lactation. Body weight and body condition score were recorded once every 2 wk throughout the experiment. Urine samples were collected at 30, 60, and 90 d of lactation and were analyzed for allantoin and creatinine. Least squares means for intake, milk yield, and milk composition were unaffected by treatment. The allantoin to creatinine ratio was not affected by treatment. Yeast cultures with or without enzyme had no direct effects on prepartum or postpartum dry matter intake or milk yield and composition.