日粮中添加不同处理及水平的VA对奶牛泌乳性能及乳中VA含量的影响

[目的]通过饲养试验,研究不同处理及添加剂量的维生素A对奶牛乳品质及乳中维生素A含量的影响。[方法]采用2×2随机试验设计,按照体重、泌乳量及胎次相近的原则,将24头奶牛随机分为4组,每组6头。各组在基础日粮中添加不同处理及水平的维生素A。[结果]奶牛日粮中维生素A的添加量由110 IU/kg BW提高至165 IU/kg BW,有明显减缓泌乳中后期奶牛日产奶量的下降及提高乳中维生素A含量的趋势,但其效果不如添加相同剂量的过瘤胃保护维生素A微胶囊。与未处理维生素A组相比,日粮中添加1101、65IU/kg BW过瘤胃保护维生素A微胶囊可以明显增加泌乳中后期奶牛的日产奶量,提高乳中维生素A含量,尤以165 IU/kg BW过瘤胃保护维生素A组的效果明显。[结论]奶牛饲喂过瘤胃保护维生素A能够有效提高奶牛的日产奶量,增加乳中维生素A浓度,增加日粮中维生素A的添加剂量也有增加奶牛生产性能及乳中维生素A的趋势。

Effect of Different Treatments and Levels of VA on Milk Performance and VA Content in Milk

[Objective] The experiment was conducted to study the influence of different treatments and levels of VA in dairy cows diet on the milk performance and the content of VA in milk.[Method] The experiment was a 2×2 factorial arrangement.24 dairy cows which were similar in weight and milk performance were randomly divided into 4 groups,with 6 per group.Different groups were added the different treatments and levels of VA.[Result]The adding level of VA in diet from 110 IU/kg BW to 165 IU/kg BW had a tendence of effect on increasing the milk yield and VA in milk,but the effect was lower than the group of adding ruminal protected VA.Supplement of microcapsules of ruminal protected VA(110 and 165 IU/kg BW,respectively)in diet could significantly increase milk yield and VA in milk.And the effect of the group of 165 IU/kg BW ruminal protected VA was better than that of the group of 110 IU/kg BW ruminal protected VA.[Conclusion] Ruminal protected VA fed in diet of dairy cows could effectively improve the milk yield and raise the VA content in milk.And increasing adding level of VA had the same tendence.