Effect of Yeast Culture and Sodium Bicarbonate on Milk Yield and Composition in Dairy Cows

Effect of dietary added yeast culture with or without NaHCO3 supplementation on milk production responses of 20 midlactation Holstein cows was determined in a 10-wk experiment. The control diet consisted of 40% corn silage and 60% concentrate on a DM basis. At the end of 2-wk preliminary period, cows were randomly assigned to either 0 or .75% sodium bicarbonate (DM basis) for the remainder of the study. Cows within each NaHCO3 group received either 0 or 1% dietary added yeast culture (DM basis) during wk 3 through 6 and application of yeast culture treatments were reversed during wk 7 through 10. Yeast culture and NaHCO 3 had no effect on DM intake, milk yield, or milk composition. However, there was a tendency for increased milk protein percent with added yeast culture and a tendency for increased daily production of 4% FCM and gross efficiency of FCM production with added yeast culture and NaHCO3. Dietary supplemented yeast culture either alone or in combination with NaHCO3 had no beneficial effect on milk production and DM intake of midlactation cows fed 40% corn silage diets.