Effects Of Bacillus Megateriumm On Performance,Rumen Fermentation And Biochemical Parameters Of Dairy Cows

In this experiment,in situ technique was used to study the effects of Bacillus megateriumm on performance,rumen fermentationand and biochemical parameters of Chinese Holstein dairy cows.24 Holstein cows with similar milk yield,day in milk and parity were used and divided into 4 treatments with a randomized block design. Bacillus megateriumm,at doses of O(control), 5,10 and 15g/d were reached in the total mixed ration,respectively. The experiment was conducted over a period of 11 weeks,including 2 weeks for adaptation and 9 weeks for data collection. The results were showed as follows:1.Effects of Bacillus megateriumm on production performance,milk quality nutrition and digestibility of dairy cows. The results showed as follows,4% FCM yield was the highest in 15g/d group.significantly higher than in the control group(P<0.05);Milk fat percentage was the highest in lOg/d group,significantly higher than in the control group(P<0.05);Milk protein percentage was the highest in lOg/d group,significantly higher than in the control group(P<0.05);Lactose percentage percentage was the lowest in lOg/d group,significantly lower than in the control group(P<0.05);Milk urea nitrogen concentration in 5-15g/d group was significantly higher than in the control group(P<0.05);The digestibility of NDF in 15g/d was significantly higher than in the control group(P<0.05);there were no significant differences between other experimental groups and control group in Milk yield,feed efficiency and Milk total olids percentage(P>0.05).2.Effects of Bacillus megateriummne supplementation on rumen fermentation, microprotein synthesis,and bacterial abundance. The results indicated that,rumen pH in 10g/d were significantly higher than in the control group(P<0.05);Acetate content was the lowest in10g/d,significantly lower than in the control group(P<0.05);Propionate content was the highest inlOg/d,significantly higher than in the control group(P<0.05);Acetate:propionate ratio was the lowest inlOg/d,significantly lower than in the control group(P<0.05);Protozoa protein content in10g/d group were higher than in the control group(P<0.05);there were no significant differences between other experimental groups and control group in NH3-N,TVF and butyrate(P>0.05);Firmicutes inl5g/d were higher than in the control group (P<0.05),Fibrobacter in lOg/d were higher than in the control group (P<0.05),Succiniclasticum in 5g/d and 15g/d were higher than in the control group (P<0.05),Pseudobutyrivibrio in 10-15g/d were higher than in the control group (P<0.05).3.Effects of Bacillus megateriumm on serum biochemical and nitrogen biochemical of dairy cows. The results showed as follows:Total protein content in5-10g/d group were higher than in the control group(P<0.05);ALB content in5g/d group were higher than in the control group (P<0.05);GLOB content was the lowest in the control group(P<0.05); ALT content was the highest in 15g/d(P<0.05); BUN content in 5g/d and 15g/d were higher than in the control group (P<0.05);Faeces BUN content inl5g/d group was lower than in the control group(P<0.0.5);Faeces NH3-N content in lOg/d was lower than in the control group(P<0.05);BUN Of urin content in 15g/d was lower than in the control group(P<0.05).Conclusion:The results of this study indicated that 10-15g/d Bacillus megaterium could improve production performance,rumen fermentation and improving the metabolism of blood nutrients and reducing the loss of N.