The Influence Of Adding Rumen Bypass Fat On Production Performance,Biochemical Indexs And Hormones Of Holstein Dairy Cows

With the improvement of milk production, the reproductive performance of dairy cows declined. Energy is one of the main factors that affect the reproductive performance of dairy cows. This study was to investigate the effects of rumen bypass fat on the production performance, blood biochemical indexes and hormone of dairy cows, and to provide scientific evidence for improving the reproductive performance of dairy cows.Experiment 1 The effects of adding rumen bypass fat on the reproductive performance of postpartum dairy cowsThe 32 first lactation Holstein dairy cows which had the similar age, body weight, body condition were selected and divided into the control group and the experimental group(n=16 respectively) by pair principle. The control group was fed the basal diet, the experiment group was fed the basal diet plus rumen bypass fat 200g/head· days. The effects of adding rumen bypass fat on the productive performance of dairy cows were studied during the postpartum 15-70 days. The results showed that the dry matter intakes (DMI) of experiment group were lower than that of the control group (P>0.05); the body condition scores of the experiment group were significantly lower than that of the control group (P<0.05); the milk yields of the experiment group were higher 1.52 kg/day than that of the control group (P>0.05); the first breeding times of the experiment group were earlier 2.37 d than that the control group (P>0.05).Experiment 2 The effects of adding rumen bypass fat on serum biochemical indexes of postpartum dairy cowsThe experimental animal’s selection, grouping and feeding patterns were same as the experiment 1, the effects of adding rumen bypass fat on blood biochemical indexes of dairy cows were studied. The results showed that, compared with the control group, the concentration of the serum glucose and insulin of the experiment group increased (P>0.05), the serum β-hydroxybutyric acid concentration decreased (P>0.05). There was no effect on serum urea nitrogen concentration (P>0.05).Experiment 3 The effects of adding rumen bypass fat on the serum hormone concentrations of postpartum dairy cowsThe experimental animal’s selection, grouping and feeding patterns were same as the experiment 1, the effect of adding rumen bypass fat on the serum hormone concentration of postpartum dairy cows. The research results showed that the serum follicle-stimulating hormone (FSH) concentration of the experiment group had peak in postpartum 28 d and 56 d, the that of the control group in postpartum 42 and 56d; the serum luteinizing hormone(LH) concentration of the experiment group had peak in postpartum 35d and 56 d respectively, and that of the control group had a peak in postpartum 35d; the serum estrogen concentrations of the experiment group were significantly lower in postpartum 56～63 d than that of the control group (P<0.05), and there was no significant difference (P>0.05) in other time point; the concentrations of serum progesterone and prostaglandins of the experiment group were higher than that of the control group (P>0.05); the serum growth hormone concentrations of the experiment group were lower than that of the control group (P>0.05).In conclusion, adding 200 g rumen bypass fat in postpartum dairy cows diet may improve the cow body condition, increase the milk yield, shorten the breeding time, raise the serum concentration of glucose, insulin, follicle stimulating hormone, progesterone and prostaglandin, may alleviate negative energy balance and improve the reproductive performance of the postpartum dairy cows.