内源酶激活剂对泌乳后期奶牛生产性能和饲料消化率的影响

Effects of an endogenous activator on production performance and feed digestibility of dairy cows in late lactation

为研究内源酶激活剂对华南地区泌乳后期奶牛产奶量、乳成分和饲料消化率的影响,试验选取60头胎次(2胎)、泌乳天数[(212.99±3.84)d]、日均产奶量[(23.18±0.67)kg]相近的中国荷斯坦奶牛,随机分为2组,对照组前后饲喂2种基础日粮(基础日粮1和2),试验组在2种基础日粮中添加60 g/d·头内源酶激活剂,预试期7 d,日粮转换过渡期5 d,每种基础日粮添加试验的正式期为14 d,正式期共计28 d。结果表明:泌乳后期奶牛随着泌乳天数的增加产奶量呈现下降趋势,相比试验前1周,基础日粮2+激活剂第2周的产奶量下降达到显著水平(P <0.05),添加内源酶激活剂对产奶量无提升作用(P> 0.05);同时,添加内源酶激活剂可一定程度上提高泌乳后期奶牛的乳脂和乳蛋白率,提高日粮氮的泌乳转化效率,降低乳中尿素氮含量,降低体细胞数,提高奶牛饲料消化率,但这些影响效应均未达到显著水平(P> 0.05)。综上,内源酶激活剂可一定程度上改善泌乳后期奶牛的乳成分,提高饲料的消化率。

The purpose of this study was to study the effects of an endogenous activator on milk yield,milk composition and feed digestibility of dairy cows in late lactation period in south China.A total of 60 Chinese Holstein cows with similar parity(second-parity),lactation day [(212.99±3.84)d] and average daily milk yield [(23.18±0.67)kg] were randomly divided into two groups(control and experimental groups).The control group was fed for two basic diets(diet 1 and 2).The experimental group was fed for two basic diets plus 60 g/d·head of the endogenous activator.Pre-trial period was 7 days.Transition period of the two diets was 5 days.Formal test of the additional trial for each basic diet was 14 days,and the two formal tests were 28 days.The results showed that milk production of dairy cows in the late lactation stage showed a decreasing trend with increasing lactation days.Compared with the first one week of the test,milk production of the basic diet 2 plus the activator in the second week was significantly decreased(P < 0.05).The activator of endogenous enzymes had no effect on milk production(P > 0.05).At the same time,the activator of endogenous enzymes could improve the milk fat and milk protein rate of dairy cows at the later stage of lactation,increase the lactation conversion efficiency of dietary nitrogen,reduce the urea nitrogen content in milk,reduce the number of somatic cells,and improve the feed digestibility of dairy cows,but these effects did not reach statistical significance(P > 0.05).In conclusion:an endogenous activator could improve milk composition and feed digestibility of dairy cows in late lactation period,but its mechanism of function in dairy cows was complex,so its effects were not significant.