Nutritive Value of Wet Brewers Grains for Lactating Dairy Cows

Abstract

Forty Holstein cows of high potential for milk production were assigned prepartum to five rations of varying protein percent and source. Protein was 85, 100, and 118% of the requirements recommended by the National Research Council. Within 100 and 118%, supplemental protein was either wet brewers grains or soybean meal. Wet brewers grains constituted 15 and 30% of ration dry matter or approximately 25 and 50% of total intake of concentrate dry matter for the 100 and 118% rations. The trial was the first 140 days of lactation. Production and composition of milk were not different between percents and sources of supplemental protein. However, production was reduced slightly by the unsupplemented ration containing 85% of recommendation. Rumen ammonia nitrogen and urea nitrogen of blood plasma were correlated with intakes of ration protein and soluble nitrogen among all rations and within rations containing soybean meal but not within rations containing wet brewers grains. Calculated energy for wet brewers grains indicated total digestible nutrients of 78% and net energy for lactation of 1.76 Mcal/kg of dry matter. These are approximately 16% greater than those listed by National Research Council. © 1981, American Dairy Science Association. All rights reserved.