EFFECT OF BUFFER ADDITION TO HIGH GRAIN TOTAL MIXED RATIONS ON RUMEN PH, FEED-INTAKE, MILK-PRODUCTION, AND MILK-COMPOSITION

Lactating Holstein cows (n = 56) were fed high grain TMR in three feed ing experiments to determine the effects of two rumen buffers on feed intake, milk production, and milk composition. The basal diet in Exper iment 1 was 40% grass silage, 12% whole cottonseed, and 48% concentrat e with treatments of 1) control (no added buffer), 2) 1.5% of dietary DM as Alkaten(R), and 3) 1.5% of dietary DM as Rumen 8(R). In Experime nt 2, diets consisted of 12% corn and sun-flower silage, 20% whole cot tonseed, and 68% concentrate with treatments as in Experiment 1. The d iets in Experiment 3 were identical to those in Experiment 2, except t hat buffers were increased to 2.2% of dietary DM. The DMI was greater for cows fed buffered diets than control diets in Experiments 2 and 3. Milk production was unaffected by treatment. Milk fat percentage was unaffected by diet in Experiment 1 and averaged 3.8%. Milk fat depress ion was alleviated for cows fed buffered diets in Experiments 2 and 3. No differences in rumen fluid pH or molar percentage of VFA were sign ificant among treatments.