AN ASSESSMENT OF DIFFERENCES IN THE RUMINAL DEGRADABILITY AND INTESTINAL DIGESTIBILITY OF CRUDE PROTEIN IN BREWER’S GRAINS AND MAIZE DRAFF

The submitted thesis aims to assess the diff erences between the ruminal degradability and intestinal digestibility of crude protein contained in brewer’s grains (BG) and maize draff (AMG). The eff ectiveness of ruminal degradability was tested using the “in sacco” method on 3 dry Holstain cows fi tted with rumen cannulas. The dynamics of ruminal degradability of crude protein (CP) was detected a er 0, 4, 8, 16, and 24 hours of samples incubation in the rumen. The intestinal digestibility of crude protein undegradable in the rumen was determined using the “mobile bag” method on 3 dry Holstain cows fi tted with duodenal cannulas. The crude protein degradability of BG was detected in the abovementioned hours (%): 4.06; 18.16; 32.40; 38.56, and 50.70; crude protein degradability of AMG: 42.04; 63.56; 84.47; 85.16, and 87.19. The eff ectiveness of rumen degradability of BG crude protein at the rate of passage of rumen content 6 % per hour was calculated at 35.33 % and that of AMG, at 76.29 %. Intestinal digestibility of BG crude protein and dry matter at the rate of passage of intestinal content 6 % per hour was calculated at 79.41 % and 22.84 %, respectively, and that of AMG, at 57.01 % and 11.33 %, respectively. The diff erences between the indicators of both feedstuff s were signifi cant (P < 0.05). The results show that BG are mostly a source of crude protein with higher intestinal digestibility than AMG.