Effect of Type and Amount of Buffer Addition to Grass Silage-Based Total Mixed Rations on Milk Production and Composition

Abstract

Thirty-six lactating cows were fed total mixed rations in two experiments to evaluate the effect of type and amount of buffer on milk production and composition and DM intake. Dietary treatments were for Experiment 1: 1) control (40% grass silage:60% concentrate), 2) control plus 1.2% sodium sesquicarbonate, and 3) control plus 1.2% sodium bicarbonate; and Experiment 2: 1) control (10% alfalfa hay:30% grass silage:60% concentrate), 2) control plus .9% sodium sesquicarbonate, and 3) control plus 1.8% sodium sesquicarbonate. Increases in percentage milk fat were observed when either buffer was fed in experiment 1. Changes in percentage milk fat observed in Experiment 2 were not significantly different. No differences were observed in actual milk produced (Experiment 1 or 2), but 4% FCM was greatest in buffered diets of Experiment 1. In a third experiment, the pH of rumen fluid of fistulated steers was monitored for the first 8 h after feeding the diets fed in Experiment 1. The pH of rumen fluid was maintained at pH 6 when both buffered rations were fed and significantly decreased when the control ration was fed. Data indicate that sodium sesquicarbonate and sodium bicarbonate are equally effective in their buffering capacity in vivo. © 1989, American Dairy Science Association. All rights reserved.