Effects of supplementing different energy levels of concentrate feed on growth performance,rumen fermentation parameters,and serum biochemical indicators of Tianzhu white yak
The experiment explored the effects of supplementing different energy levels of concentrate feed on the serum biochemical indicators,growth performance,and ruminal fermentation parameters of Tianzhu white yak.The experiment was divided into two periods:The first period involved concentrate supplementation during the winter and spring grazing period,and the second period was the lush grass grazing period without supplementation.A total of 30 healthy male Tianzhu white yak calves,aged six months and weighing(46.62±4.37)kg,were selected and randomly divided into three groups with five replicates in each group and two yaks in each replicate according to a randomized block design.The control group was normally grazed without concentrate supplementation,while the experimental group Ⅰ and group Ⅱ were supplemented with concentrate feeds with metabolizable energy of 10.83 and 11.76 MJ/kg after grazing,respectively.The initial feeding amount of concentrate was 0.70 kg per head,with an increase of 0.05 kg every 15 days,and the final supplementation amount was 1.20 kg per head.The experimental period was 365 days,with a supplementation period of 150 days during the winter and spring,and a normal grazing period of 215 days.The results showed that cold-season supplementation increased the weight and weight gain of yaks at 11,12,and 18 months of age,and during the periods of 6～11 months and 12～18 months of age(P＜0.05),with group Ⅱ having higher weight and weight gain at all ages compared to group Ⅰ(P＜0.05).The Gompertz model fit better than the Bertalantty model for all groups,with the experimental groups having higher breakpoint weights and breakpoint months than the control group,and group Ⅱ having the highest breakpoint weight and month.The ruminal fluid acetic acid content,acetic acid/propionic acid ratio,and pH value in groups Ⅰ and Ⅱ were lower than in the control group(P＜0.05),while the concentrations of propionic acid,isobutyric acid,butyric acid,isovaleric acid,valeric acid,and ammonia nitrogen were higher than in the control group(P＜0.05),and the ammonia nitrogen concentration in the group Ⅱ was higher than that in the experimental group Ⅰ(P＜0.05).The serum glucose,total cholesterol,triglycerides,and total protein concentration in groups Ⅰ and Ⅱ were higher than in the control group(P＜0.05).The study indicates that cold-season supplementation with different energy levels of concentrate feed promoted the growth and development of yak calves,altered the ruminal fermentation patterns,and serum biochemical indicators,with the supplementation of concentrate feed with a metabolizable energy of 11.76 MJ/kg showing better results.
Tianzhu white yakweightgrowth curve modelrumen fermentation parametersserum biochemical indicators
万方数据
维普
