Effect of Diet on Partial Efficiency of Acetate Use for Body Tissue Synthesis by Mature Cattle

Acetic acid was infused into the rumen of four mature nonpregnant, nonlactating Holstein cows fed different diets. Diets of either 100% alfalfa hay or 30% alfalfa hay, 57% corn, 11% soybean meal, and 2% ground limestone were fed in each of two single reversal experiments. Acetate infusion resulted in no measurable change in blood acid-base balance nor in blood plasma ketone or glucose concentration. Acetate infusion slightly increased fecal energy and decreased energy loss as methane, urine, or as both. Use of metabolizable energy from acetic acid was 27% for cows fed the 100% hay diet and 69% for cows fed the 30% hay diet. The type of basal diet fed markedly affects the partial efficiency of acetate use for body tissue synthesis by mature cattle.