Effect of Yeast on Feed Intake and Performance of Cows Fed Diets Based on Corn Silage during Early Lactation

Abstract

Thirty-six multiparous Holstein cows were fed a mixture of corn silage and concentrate [1:1; dry matter (DM) basis] and long hay (0.9 kg/d) through wk 18 of lactation. Beginning at 30 d prepartum through wk 4 of lactation, the total mixed rations of 18 of these cows were top-dressed daily with 10 g of Biomate® Yeast Plus® (Chr. Hansen's, Inc., Milwaukee, WI). The other 18 cows served as controls. At wk 5, both control and treated cows were divided into three groups and fed 0, 10, or 20 g/d of yeast. Yeast supplementation during early lactation significantly improved DM intake, milk yield, and the digestibility of crude protein and acid detergent fiber. Least squares means for DM intake, fat-corrected milk yield, crude protein digestibility, and acid detergent fiber digestibility for cows fed 0, 10, 20 g/d of yeast during wk 5 to 18 of lactation were 23.8, 24.7, and 25.0 kg/d; 37.7, 40.7, and 41.4 kg/d; 78.5, 80.8, and 79.5%; and 54.4, 60.2, and 56.8%, respectively. Although numerical responses in DM intake and milk yield were greater for cows fed 20 g/d of yeast than for cows fed 10 g/d of yeast, the response was not significant.