An assessment of differences in the ruminal degradability and intestinal digestibility of crude protein in brewer's grains and maize draff

Abstract

The submitted thesis aims to assess the differences between the ruminal degradability and intestinal digestibility of crude protein contained in brewer’s grains (BG) and maize draff (AMG). The effectiveness of ruminal degradability was tested using the “in sacco” method on 3 dry Holstain cows fitted with rumen cannulas. The dynamics of ruminal degradability of crude protein (CP) was detected after 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 fitted with duodenal cannulas. The crude protein degradability of BG was detected in the above-mentioned 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 effectiveness 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 differences between the indicators of both feedstuffs were significant (P < 0.05). The results show that BG are mostly a source of crude protein with higher intestinal digestibility than AMG.