Quality Evaluation Of Whole Plant Corn And Corn Stalk And Its Effect On The Growth Performance And Rumen Microbial Community Of Beef Cattle

The objective of this study was to investigate the differences in silage quality and degradation characteristics in the rumen of whole plant corn and corn stalk silage with or without silage additives,and to study the growth performance,economic benefits,apparent digestibility of nutrients and rumen microbial community of beef cattle through feeding experiments.The experiment was divided into three parts,the first test,the quality of the whole plant corn and corn stalk silage and its degradation characteristics in the rumen;the second experiment,the effect of the whole plant corn and corn stalk silage on the growth performance,economic benefits and the apparent digestibility of feed nutrients of beef cattle;Experiment 3,Effects of whole plant corn and corn stalk silage on rumen microflora community of beef cattle.The main results of the test are as follows;Exp.1: After silage was completed,sample were taken for quality analysis.The results showed that:(1)Adding silage additives had no significant difference on the PH value and lactic acid content of whole plant corn and corn stalk silage(P>0.05);The content of NDF and ADF in whole plant corn silage was significantly reduced after the addition of silage additive(P<0.05),and the content of DM and CP increased(P>0.05).Thus the silage quality of whole plant corn silage was improved.(2)To some extent,used the silage additives increased the effective degradation rate of DM,CP,NDF and ADF in the rumen of whole plant corn and corn stalk silage,but the difference was no significant(P>0.05).The effective degradation rate of DM and CP in whole plant corn silage and inoculated whole plant corn silage was significantly higher than that of corn stalk silage and inoculated corn stalk silage(P<0.05),but the effective degradation rate of NDF and ADF was not significant(P>0.05).(3)The 72 h degradation rate of whole plant corn silage and inoculated whole plant corn silage DM was significantly higher than that of corn stalk silage and inoculated corn stalk silage(P>0.05),but the whole plant corn silage and inoculated whole plant corn silage,corn stalk silage and inoculated corn stalk silage had no significant differences(P>0.05).There was no significant difference in the degradation rates of CP,NDF and ADF at 72 h(P>0.05).kg)and similar ages(about 18 months of age)were randomly assigned to 4 treatment groups,6 repetitions per treatment group,each repeate 5 beef cattle according to varitty,body weight and age as much as possible,using complete random single factorial design.The whole plant corn silage(WS),inoculated whole plant corn silage(LWS),corn stalk silage(CS)and inoculated corn stalk(LCS)were fed respectively.The results of beef feefing test shaowed that:(1)Among the treatment groups average daily dry matter intake had no significant difference(P>0.05);compared with CS group,average daily gain,F/G in LCS group decreased,but the difference was not significant(P>0.05);the average daily gain in WS and LWS group significantly increased(P<0.05),F/G significantly decreased(P<0.05).(2)Compared with CS and LCS group,DM,OM,CP,ADF and NDF apparent digestibility were significantly increased in WS and LWS group(P<0.05);The use of silage additive has no significant difference in the apparent digestibility of all the nutrients of the whole plant corn and corn stalk silage group(P>0.05).(3)The serum TC content in LWS was lower than that in LCS(P<0.05),and the other serum biochemical indexes were not significantly different among all the treatment groups(P>0.05).(4)The LWS had the highest average daily profit,which was slightly higher than WS,and the average daily profit of LWS increased by 51.66 % and 50.62% respectively,compared with CS and LCS group.Exp.2: A total of 120 Simmental hybrids with disease-free,similar body weights(about 450Exp.3: Microbial diversity and composition of rumen microorganism were systematically analyzed,The results showed that: The abundance index(ACE and Chao index)and diversity index(Simpson)of each treatment group had no significant difference(P<0.05),compared with the CS and LCS group,the diversity index(Shannon index)of WS and LWS group increased significantly(P<0.05);At the phylum level,Bacteroidetes,Firmicutes,and Proteobacteria were the three dominant strains of each treatment group,and the relative abundance of thick-walled bacteria in the CS group was significantly lower than that in the WS and LCS groups(P<0.05),not significantly different from LWS(P>0.05).The relative abundance of Proteobacteria was the highest in CS group,and it was significantly different from the other three groups(P<0.05).There was no significant difference between WS group and LWS group(P>0.05),which was significantly lower than that of LCS group(P<0.05).At the genus level,Prevotella was the dominant genus of each treatment group,and the relative abundance of Prevotella in each treatment group was not significantly different(P>0.05).