Effects Of Sweet Sorghum Silage On The Performance,blood Biochemical Indexes And Rumen Function Of Dairy Cows

In this study,Holstein cows in the middle stage of lactation were chose as the experimental animals to study the effects of replacement of 0%,25%and 50%whole corn silage in dairy cow diets with sweet sorghum silage on the production performance,dairy quality,blood biochemical indexes,rumen fermentation parameters and rumen microbial structure of cows under the condition of energy and nitrogen balance.Thirty health Holstein cows were randomly divided into three groups with 10 dairy cows and fed different proportion[0%(control group),25%(trial 1),and 50%(trial 2)]of corn silage in diets were replaced with equivalent the sweet sorghum silage.The pretrial lasted for 10 d,and the trial lasted for 50 d.The test results are as follows:(1)The replacement of whole corn silage with sweet sorghum silage had no significant effects on milk protein rate,milk fat rate,lactose rate,milk urea nitrogen,total solids,milk cell number and other lactation performance,but had significant effect on milk yield(P<0.01)(2)In terms of blood biochemical indexes,sweet sorghum had no significant effects on serum concentrations of total protein,total cholesterol,glucose,glutamate transaminase,alanine transaminase,calcium and phosphorus(P>0.05),but had significant effects on serum albumin,urea nitrogen and triglycerides(P<0.05).(3)In terms of rumen fermentation parameters,sweet sorghum had no significant effects on rumen pH value,acetic acid,propionic acid,butyric acid,isobutyric acid,valeric acid,iso-valeric acid and total volatile fatty acids(P>0.05).However,it had a significant effect on the ratio of acetic acid to propionic acid and the ratio of valeric acid in total volatile fatty acids(P<0.05).(4)16S rDNA sequencing was conducted.The results showed that sweet sorghum had no significant effect on the Alpha diversity of rumen microorganisms(P>0.05).Analysis at the level of phylum showed that Firmicutes,Bacteroidetes,Proteobacteria and Patescibacteria were the dominant phyla.Bray-curtis distance was used for clustering,and a cluster map was drawn.It was found that the control group and the trial 1 was the same cluser,and the trila 2 was another cluster.In summary,the whole corn silage can be replaced with the sweet sorghum silage,and the optimum proportion was 50%under this experimental conditions.