蛋氨酸羟基类似物异丙酯对奶牛产奶性能和血清生化指标的影响

选择24头健康荷斯坦奶牛进行配对,随机分为两组,每组12头.对照组仅饲喂基础日粮,试验组在饲喂基础日粮的同时,从产前21 d开始在日粮中添加20 g·d-1蛋氨酸羟基类似物异丙酯(HMBi),产后添加量根据配方设定为30 g·d-1.结果表明:与对照组相比,试验组奶牛每天的产奶量提高了6.83 kg(P0.05),牛奶中的乳蛋白率升高了0.14个百分点(P0.05),体细胞数下降了26.80万个·m L-1(P0.01).产前14 d时,试验组奶牛血清中的球蛋白含量和尿素氮浓度升高,免疫球蛋白G(IgG)含量降低(P0.05);产后14 d时,试验组血清中的总胆固醇浓度降低(P0.01);产后70 d时,试验组奶牛血清中的总胆固醇浓度也降低(P0.05).结论:在日粮中添加HMBi可以提高奶牛的产奶量,改善血清生化指标,促进机体的脂代谢;同时提高牛奶的乳蛋白含量,有效降低体细胞数.

Effects of 2-hydroxy-4-( methylthio) butanoic acid isopropyl ester on production performance and serum parameters in dairy cows

To evaluate effects of 2-hydroxy-4-( methylthio) butanoic acid isopropyl ester ( HMBi) on milk yield and composition and serum biochemical indicators of dairy cow, 24 Holstein cows were randomized into 2 groups, with the control fed with basal diet only and the treatment group fed with diet containing 20 g?d-1 HMBi ( 21 days before parturition ) and 30 g?d-1 HMBi ( 80 days after parturition) . The trial lasted from 21 days before parturition to 80 days after parturition. Results showed that milk yield from the treatment group increased by 6.83 kg?d-1( P>0.05) compared with the control. Milk protein content increased by 0.14% ( P<0.05) and somatic cell counts ( SCC) decreased ( P<0.01) . Fourteen days before parturition, globulin and urea nitrogen levels increased while immunoglobulin G (IgG) level decreased (P<0.05). Furthermore, total cholesterol level reduced from 14th day (P<0.01) and 70th day ( P<0.05) after parturition. To summarize, HMBi addition improves milk yield and protein, serum globulin and urea nitrogen while decreases milk SCC and serum IgG.