Effects of Different Proteins and Carbohydrates on Rumen Microbial Protein Degradation and Synthesis

摘要

Optimisation of diets in cows is essential to achieve the best possible performance from these animals. Here, researchers sought to investigate the effects of diet on ruminal microbial protein degradation and synthesis in cows. Three ruminally fistulated Chinese Yellow heifers were used in a 3x3 Latin square trial to study the kinetics of rumen degradation of corn stover. Three diets were formulated to contain corn plus soybean meal (diet 1), corn plus pig blood meal (diet 2) and wheat plus soybean meal (diet 3). Each heifer was allowed a 30 days adaptation following by a 7 day a rumen evacuation in situ during which rumen content was evacuated 0, 2, 4, 8, 16 or 24 h after feeding. Dry Matter (DM) intakes were similar for all diets. The result of rumen evacuation showed that rumen NH3-N pooling peaked 8 h after feeding for diets 1 and 3. Moreover, rumen Volatile Fatty Acid (VFA) pooling varied depending on DM retention for all 3 diets and rumen DM, Neutral Detergent Fibre (NDF) and Acid Detergent Fibre (ADF) poolings were lowest for diet 1 at 4, 8 and 16 h after feeding, respectively (p<0.05). Therefore, diet 1, containing corn plus soybean meal, resulted in low rumen DM, NDF and ADF pooling but high DM, NDF and ADF degradability in the rumen of Chinese Yellow heifers. These results shed light on ruminal processes and will aid in the development of optimal diets in cows.