Ruminal Degradation of Dried Brewers Grains, Wet Brewers Grains, and Soybean Meal

A series of trials was conducted to determine the ruminal degradation of nitrogenous compounds and dry matter of soybean meal, wet brewers grains, and dried brewers grains. In situ and in vitro estimates of degradation were positively correlated but yielded different absolute values for measures of ruminal degradation. Ruminal digestion of protein, predicted from in situ data, was 42, 73, and 83% for brewers dried grains, brewers wet grains, and soybean meal. Drying of wet grains at either 50 or 150°C increased resistance to ruminal digestion equally. Measurements of flow of dry matter and nitrogen of feed origin to the duodenum were made in vivo for diets containing either brewers dried grains or soybean meal. Negative apparent digestibility of nitrogen in the rumen for a 13% crude protein, brewers dried grains ration indicates the potential for using a nonprotein nitrogen supplement with this ration. Resistance to digestion of nitrogen from brewers dried grains occurred only in the rumen. Amino acid patterns delivered to the small intestine and digestion of duodenal contents were similar for diets containing brewers dried grains or soybean meal.