Effect of Sodium Bicarbonate on Rate of Passage and Degradation of Soybean Meal in Postpartum Dairy Cows

Open Access
Publisher Website
Google Scholar
Abstract
Effects of sodium bicarbonate on rate of passage and disappearance of soybean meal from the rumen were determined in a change-over experiment with 8 [Holstein] cows. Experimental diets containing 50 or 60% roughage were fed over 5 21-day periods with 4 cows per diet. Sodium bicarbonate at 1.0 and 2.5% (diet dry matter) were changed over in periods 2 and 4; periods 1, 3 and 5 served as control. Rate of passage of soybean meal was measured with chromium-mordanted soybean meal and rate of disappearance by nylon bag technique. Effects of diet were similar for all responses. Response to the 2 percents of buffer was similar for dry matter intake, milk yield, milk fat and protein. Percent buffer fed was associated positively with ruminal pH and with disappearance of N from nylon bags. The 0, 1 and 2.5% of buffer resulted in turonver rates of mordanted soybean meal of 8.22, 9.80 and 10.52% per h, but degradation of protein remained relatively constant at 36.0, 38.4 and 38.2%. The influence of rate of passage on ruminal degradability is discussed.