日粮添加纤维素酶对奶牛生产性能、乳成分及瘤胃发酵的影响OA

This study explored the effects of dietary cellulase supplementation on production performance,milk composition,and rumen fermentation in dairy cows.We selected 160 similar healthy Holstein cows,randomly dividing them into four groups(four replicates,10 cows each).The control group got a basal diet;the other three got the basal diet plus cellulase at 1 g/kg,1.5 g/kg,and 2 g/kg.The experiment included a 7-day pre-trial and a 30-day formal trial.Results:1)When dairy cows were supplemented with cellulase at concentrations of 1 g/kg,1.5 g/kg,and 2 g/kg,in comparison to the control group,their dry matter intake exhibited reductions of 6.28％,11.08％,and 11.40％correspondingly,and these reductions were statistically significant(P<0.05).Concurrently,the average daily milk production of the dairy cows rose by 3.49％,3.98％,and 6.53％respectively,and the milk-to-feed ratio also significantly increased of 10.00％,17.86％,and 19.29％respectively,with all these changes demonstrating significant differences(P<0.05).2)Compared to the control group,dietary supplementation with cellulase at doses of 1 g/kg,1.5 g/kg,and 2 g/kg resulted in an increase in milk fat percentage,although the difference was not significant(P>0.05).Additionally,no significant changes were observed in milk protein percentage and lactose percentage among the groups(P>0.05).3)When dairy cows were given cellulase in their diet at 1 g/kg,1.5 g/kg,and 2 g/kg,rumen levels of total volatile fatty acids and propionic acid rose significantly compared to the control group(P<0.05).Meanwhile,acetic acid and ammonia nitrogen levels in the rumen dropped significantly(P<0.05),and the acetic acid-to-propionic acid ratio also decreased significantly(P<0.05).Conclusion:Dietary supplementation with an appropriate amount of cellulase exerts certain positive effects on the production performance,milk composition,and rumen fermentation of dairy cows.In this experiment,the most pronounced effects were observed at a supplementation dose of 2 g/kg.