饲粮精粗比对空怀母牛体况、繁殖激素分泌及血浆生化指标的影响

Effects of Dietary Concentrate to Forage Ratio on Body Condition,Reproductive Hormone Secretion and Plasma Biochemical Indices of Empty-Breasted Cows

本试验旨在研究饲粮精粗比对空怀母牛体况、繁殖激素分泌及血浆生化指标的影响。采用完全随机设计,将90头体况相近、年龄相近且体况偏瘦的空怀母牛[(387.2±22.6)kg]平均分为3组,分别饲喂高精粗比饲粮(精粗比65∶35,HCD组)、中精粗比饲粮(精粗比50∶50,MCD组)及低精粗比饲粮(精粗比35∶65,LCD组)。预试期15 d,正试期60 d。结果表明:在正试期第60天时,MCD组和HCD组母牛的体重和体况评分高于LCD组,但差异不显著(P>0.05);MCD组和HCD组母牛的平均日增重(ADG)和体况变化均显著高于LCD组(P<0.05);LCD组母牛的发情率显著低于其他2组(P<0.05)。在正试期第30天时,HCD组和MCD组母牛的血清促黄体素(LH)浓度显著高于LCD组(P<0.05);MCD组母牛的血清雌二醇(E_(2))浓度显著高于LCD组(P<0.05)。在正试期第45天时,HCD组和MCD组母牛的血清LH、促卵泡素(FSH)和E_(2)浓度均显著高于LCD组(P<0.05)。MCD组血清LH和FSH浓度在发情时达到最高,且显著高于LCD组(P<0.05)。在正试期第20天时,HCD组和MCD组母牛的血浆葡萄糖含量均显著高于LCD组(P<0.05);在正试期第40天时,HCD组母牛的血浆葡萄糖和甘油三酯含量均显著高于LCD组(P<0.05),HCD组和MCD组母牛的血浆尿素氮含量显著低于LCD组(P<0.05);在正试期第60天时,HCD组和MCD组母牛的血浆葡萄糖含量显著高于LCD组(P<0.05),HCD组母牛的血浆甘油三酯含量显著高于其他2组(P<0.05),MCD组母牛的血浆尿素氮含量显著低于LCD组(P<0.05),且有低于HCD组的趋势。上述结果表明,提高饲粮精料比可改善体况偏瘦空怀母牛的能量和蛋白质代谢水平,进一步改善母牛体况,且可有效地促进母牛机体内繁殖相关激素的分泌并缩短发情间隔。

This experiment was conducted to investigate the effects of dietary concentrate to forage ratio on body condition,reproductive hormone secretion and plasma biochemical indices of empty-breasted cows.This experiment adopted a completely random design method,and equally divided 90 empty-breasted cows[(387.2±22.6)kg]with similar body condition,similar age,and thin body condition into 3 groups.Cows in the 3 groups were fed high concentrate to forage ratio diet(concentrate to forage ratio=65∶35,HCD group),medium concentrate to forage ratio(concentrate to forage ratio=50∶50,MCD group)and low concentrate to forage ratio diet(concentrate to forage ratio=35∶65,LCD group).The pre-test period was 15 days,and the trial period was 60 days.The results showed as follows:on the 60th day of the trial period,the body weight and body condition score of the cows in the MCD and HCD groups were higher than those in the LCD group,but the difference was not significant(P>0.05);the average daily gain(ADG)and the body condition changes of the cows in the MCD and HCD groups were significantly higher than those in the LCD group(P<0.05);the estrus rate of the cows in the LCD group was significantly lower than that in the other two groups(P<0.05).On the 30th day of the trial period,the serum lutropin(LH)concentration of the cows in the HCD and MCD groups was significantly higher than that in the LCD group(P<0.05);the serum estradiol(E_(2))concentration of the cows in the MCD group was significantly higher than that in the LCD group(P<0.05).On the 45th day of the trial period,the serum LH,follicle-stimulating hormone(FSH)and E_(2) concentrations of the cows in the HCD and MCD groups were significantly higher than those in the LCD group(P<0.05).Serum LH and FSH concentrations in the MCD group reached the highest in estrus,and were significantly higher than those in the LCD group(P<0.05).On the 20th day of the trial period,the plasma glucose content of the cows in the HCD and MCD groups was significantly higher than that in the LCD group(P<0.05);on the 40th day of the trial period,the plasma glucose and triglyceride contents of the cows in the HCD group were significantly higher than those in the LCD group(P<0.05).The plasma urea nitrogen content of the cows in the HCD and MCD groups was significantly lower than that in the LCD group(P<0.05);on the 60th day of the trial period,the plasma glucose content of the cows in the HCD and MCD groups was significantly higher than that in the LCD group(P<0.05),and the plasma triglyceride content of the cows in the HCD group was significantly higher than that in the other two groups(P<0.05),and the plasma urea nitrogen content of the cows in the MCD group was significantly lower than that in the LCD group(P<0.05),and lower than that in the HCD group.The above results indicate that increasing the ratio of dietary concentrate to forage can improve the energy and protein metabolism of lean and empty cows,further improve the cow’s body condition,and can effectively promote the secretion of reproductive hormones in the cow’s body and shorten the estrus interval.