A Comparison of Effects of Dietary Glycerol versus Corn Grain on Milk Composition in Dairy Cows
The effects of glycerol on milk protein yield were investigated in this study. Twelve multiparous lactating dairy cows were assigned to diets in a repeated 3 x 3 Latin square design. The diets were a 70%-forage basal diet, the basal diet with ground and high-moisture corn replacing forages, and the basal diet with refined glycerol. The diets were fed for 28-day periods and milk, feed and blood samples were collected. Dry matter intake and milk production were stimulated on the treatment diets. Milk protein yields were stimulated by corn and further stimulated by glycerol. With the exception of BCAA, which were significantly depressed in response to the glycerol treatment, plasma concentrations of NEAA and EAA were not affected by dietary treatments. There was evidence that glycerol stimulated milk protein yield to a greater extent than corn, which was supported by the drop in BCAA on the glycerol diet.