Effects of Rumen-Mate on lactational performance of Holsteins fed a high grain diet

Three Latin-square trials were conducted to determine the effects of supplementing Rumen-Mate, a commercial buffer containing KCl, NaCl, and Mg and Na carbonates, on lactation performance of Holsteins. Cows were fed a basal ration of 40% corn silage and 60% concentrate in Trials 1 and 2, and 40% corn silage, 55% concentrate, and 5% alfalfa hay in Trial 3 (DM basis). In Trial 1, treatments were: basal diet, or basal diet supplemented with either 1% NaHCO3, or 1, 3, or 4.4% Rumen-Mate. Increasing dietary Rumen-Mate resulted in a linear increase in milk fat production and concentration with no difference between 1% Rumen-Mate and 1% bicarbonate. There was a significant linear decrease in milk protein concentration, but not production, with increasing concentrations of Rumen-Mate. In Trial 2 treatments were: basal diet, or basal diet supplemented with either .8% NaHCO3, 2.6% Rumen-Mate, .5% MgO, .8% NaHCO3 plus .5% MgO, or 1.8% Rumen-Mate plus .8% NaHCO3. Organic matter and CP intakes and milk protein yield and concentration were decreased by Rumen-Mate with a nonsignificant increase in milk fat concentration. Data from Trials 1 and 2 were combined with data from Trial 3, which compared basal diet, 1% bicarbonate, and 3% Rumen-Mate. The combined data showed a larger increase over basal diet in milk fat yield and concentration for 2.6 to 3% Rumen-Mate vs. .8 to 1% bicarbonate. Rumen-Mate did not decrease DM intake or protein yield relative to basal diet but did decrease protein yield 34 g/d compared with that of bicarbonate.