阴阳离子平衡对泌乳前期热应激奶牛血液生化指标的影响

研究不同水平日粮阴阳离子平衡对泌乳前期热应激奶牛血液生化指标的影响,随机将32头奶牛分为4组,日粮阴阳离子平衡(DCAB)分别为对照185 mEq/kgDM、试验Ⅰ组243 mEq/kgDM、试验Ⅱ组317 mEq/kgDM、试验Ⅲ组442 mEq/kgDM)。结果表明:(1)增加DCAB水平可以提高血液的pH值及HCO3-浓度,降低CO2分压,差异均不显著(P>0.05),唯有试验Ⅲ组TCO2下降显著(P<0.05)。(2)随着DCAB水平的增加,血清ALP增加(P>0.05)、血清CK降低(P>0.05);试验Ⅰ组血清TALT高于对照组,其他试验组均低于对照组(P>0.05)。(3)试验Ⅱ组血清Na+、K+浓度最高,Na+组间差异显著(P<0.05);血清Cl-浓度随着DCAB的增加而降低,差异不显著(P>0.05);血清Ca2+呈二次曲线变化,差异不显著(P>0.05)。(4)试验组T3含量均高于对照组,试验组血清COR、T4含量均低于对照组,试验Ⅰ、Ⅱ组血清PRL含量高于对照组,而试验Ⅲ组则降低,差异均不显著。(5)试验Ⅰ、Ⅱ组血清GLU分别比对照组含量增加,而试验Ⅲ组则显著下降(P<0.05)。试验Ⅰ、Ⅱ组血清BUN含量比对照组增加显著(P<0.05),试验Ⅲ组则低于对照组0.78%,其中试验Ⅰ组血清BUN最高。综合DCAB对血液缓冲能力、激素和酶水平等方面考虑,在泌乳前期DCAB为275 meq/kgDM时饲喂效果较好。

Effects of Dietary Cation Anion Balance on Blood Biochemical Parameters of Heat Stressed Early Lactation Dairy Cows

To study the effects of DCAB on blood biochemical parameters of heat stressed early lactation dairy cows 32 cows in early lactation were selected respectively,and assigned randomly into 4 groups(DCAB of the control group was 185 mEq/kgDM,that of the test groupⅠwas 243 mEq/kgDM,that of the test groupⅡwas 317 mEq/kgDM,and that of group Ⅲ was 442 mEq/kgDM).The main results showed as follows:(1) increasing dietary cation-anion(DCAB) can increase blood pH levels,and HCO3-concentration and reduce the CO2 partial pressure,the difference was not significant(P>0.05),TCO2 of group Ⅲ significantly decreased(P<0.05).(2)With the increasing in the level of DCAB levels,serum ALP increased(P>0.05),serum CK decreased(P>0.05);serum TALT was higher than in group Ⅰ,but lower in the other test groups than in the control group(P>0.05).(3) Serum Na+,K+ concentrtions in test group Ⅱ were the highest,Na+ concentrtions were significantly different(P<0.05) in the group;serum Cl-concentration decreased as DCAB increased,the difference was not significant;serum Ca2+ changed in a quadratic curve,the difference was not significant(P>0.05).(4) T3 contents in the experimental groups were higher,but serum COR,T4 levels were lower than in the control group,serum PRL levels in test group Ⅰ,Ⅱwere higher,but lower in group Ⅲ,the differences were not significant.(5)Serum GLU in test groups Ⅰ,Ⅱ increased,but decrese significantly in group Ⅲ(P<0.05).Serum BUN levels in test groups Ⅰ,Ⅱ significantly increased compared with the control group(P<0.05),that in group Ⅲ was 0.78% lower than that in the control group,serum BUN was the highest in groupⅠ.Considering the blood buffering capacity,hormone and enzyme levels,DCAB at the level of 275 meq/kgDM had good effect in the early lactation stage.