DCAB对热应激奶牛产奶量和乳成分的影响

Effects of DCAB on Milk Yield and Composition of Heat-stressed Cows

为研究日粮阴阳离子平衡(DCAB)对泌乳期热应激奶牛生产性能的影响,选取试验奶牛64头,分为8组,每组8头,日粮DCAB分别为泌乳前期:A1组(DCAB为185 mEq/kgDM)、B1组(DCAB为243mEq/kgDM)、C1组(DCAB为317mEq/kgDM)、D1组(DCAB为442mEq/kgDM);泌乳中后期:A2组(DCAB为83mEq/kgDM)、B2组(DCAB为172mEq/kgDM)、C2组(DCAB为217 mEq/kgDM)、D2组(DCAB为357 mEq/kgDM)。结果表明:在一定范围内增加日粮DCAB,能提高泌乳前期奶牛的产奶量,各组间差异不显著(P>0.05),B1组奶牛产奶量较高,乳蛋白、乳密度显著高于其他组(P<0.05);日粮高DCAB水平能显著增加泌乳中后期热应激奶牛的产奶量(P<0.05),乳蛋白含量随DCAB增加呈二次变化,差异显著(P<0.05),乳脂肪随DCAB的增加而增加,D2组显著高于其他试验组(P<0.05)。综合产奶量和乳成分分析,泌乳前期日粮DCAB为243 mEq/kgDM、泌乳中后期日粮DCAB为217 mEq/kgDM时能提高奶牛的产奶性能,利于奶牛机体健康和生产高质量牛奶。

Sixty four cows were divided into eight groups to study the effects of DCAB on performance of heat-stressed cows in different lactating periods. Four groups were for early lactating cows： group A1 （ DCAB, 185 mEq/kgDM ）, groupB1 （ DCAB, 243 mEq/kgDM ）, group C 1 （DCAB, 317 mEq/kgDM ）, group D1 （ DCAB, 442 mEq/kgDM ） ; the other four groups were for late lactating cows： group A2 （DCAB, 83 mEq/kgDM ）, group B2 （DCAB, 172 mEq/kgDM ）, group C2 （DCAB, 217 mEq/kgDM ）, group D2 （DCAB, 357 mEq/kgDM ）.The results indicated that, for early lactating cows, within a certain range , the increase of DCAB level could improve milk production , there were no significant differences between groups（P〉0.05 ）, the milk protein and milk density in group B 1 were significantly higher than those in other groups（P〈0.05 ） ; for late lactating cows, the diets with high DCAB levels could significantly increase the milk yield（P〈0.05 ） and milk protein（P〈0.05 ）, milk fat in the D2 group was higher than those in the other groups（P〈0.05 ）.It was concluded that the suitable DCAB levels for the early and late lactating cows were 243 mEq/kgDM and 217 mEq/kgDM respectively.