Effects of different crude feed composition on rumen microflora and rumen fermentation parameters of dairy cows in mid-to-late lactation
This experiment was conducted to investigate the effects of replacing high quality alfalfa hay with oat hay combined with rumen lysine and methionine additives on rumen microbial flora and parasite composition,abundance and rumen fermentation parameters of dairy cows,so as to reduce the dependence of dairy cows on alfalfa and achieve precise feeding and fine feeding.Forty-five healthy Holstein dairy cows in mid-to-late lactation were divided into 3 groups with 15 cows per group(15 replicates per group and 1 cow per replicate)according to the principle of similar milk yield,parity and lactation days,and fed TMR composed of three different crude feedstocks,respectively.High quality alfalfa hay was partially replaced by oat hay combined with rumen lysine and methionine additives in test group 1,alfalfa hay in test group 2 and oat hay in test group 3.The pre-experimental period lasted for 7 days and the experiment lasted for 56 days.The results showed as follows:(1)At the phylum level,the main bacteroidetes in rumen fluid of dairy cows in the three experimental groups were Bacteroidetes,Firmicutes and Fibrinobacteria.The rumen abundance of Firmicutes in alfalfa group was significantly higher than that in oat group(P＜0.05),but there was no significant difference between rumen amino acid group and alfalfa group(P＞0.05).Compared with alfalfa group,rumen amino acid group and oat group had a tendency to increase the abundance of Bacteroidetes.At the genus level,the abundances of Prevotella were the highest,compared with alfalfa group,the abundances of Prevotella in rumen amino acid group and oat group had an increasing trend,but did not reach a significant level(P＞0.05).The abundance of Vibrio butyricum in alfalfa group was the highest,which was significantly higher than that in oat group(P＜0.05),but there was no significant difference between rumen amino acid group and alfalfa group(P＞0.05).The rumen protozoa of dairy cows mainly belonged to the subphylum cilium,and there was no significant difference among experimental groups(P＞0.05).(2)Ruminal fluid pH of cows in the three experimental groups were all within the normal range.The concentration of NH3-N in rumen amino acid group and alfalfa group was significantly higher than that in oat group(P＜0.01).The MCP concentration in alfalfa group was the lowest,and that in oat group was significantly higher than that in alfalfa group(P＜0.01).The yield of TVFA,acetic acid,propionic acid,butyric acid and valeric acid in rumen amino acid group was superior to that in alfalfa group and oat group(P＜0.01),and the TVFA yield in rumen amino acid group was significantly superior to that in alfalfa group and oat group(52.71％and 37.05％higher than that in alfalfa group and oat group,respectively).Acetic acid production in rumen amino acid group was significantly increased by 52.32％and 41.04％compared with that in alfalfa group and oat group(P＜0.01).The yield of propionic acid in rumen amino acid group＞oat group＞alfalfa group,rumen amino acid group and oat group was significantly higher than that in alfalfa group(P＜0.01),rumen amino acid group was significantly higher than that in oat group(P＜0.05);The yield of butyric acid in rumen amino acid group was significantly higher than that in alfalfa group and oat group(P＜0.05);The yield of valerate in rumen amino acid group was significantly higher than that in alfalfa group(P＜0.01),and significantly different from that in oat group(P＜0.05).In conclusion,the comprehensive evaluation showed that the TMR diet with oat hay combined with lysine and methionine additives replacing part of high quality alfalfa hay could stabilize rumen microflora,ensure good rumen fermentation,appropriately reduce the quality of hay,lysine and methionine supplement protein deficiency.The formula of low alfalfa diet could be popularized and applied in production.
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万方数据
维普
