日粮阴阳离子平衡对高温环境中奶牛生产性能和血液指标的影响

Effects of Dietary Cation-anion Balance on Performance and Blood Biochemical Parameters of Dairy Cows in Hot Environment

选择泌乳前期奶牛15头,随机分成3组,每组5头,采用3×3重复拉丁方设计,分别饲喂3种不同日粮阴阳离子平衡(DCAB)的日粮,其中对照组A(DCAB为83meq/kgDM),B组(DCAB为275meq/kgDM),C组(DCAB为425meq/kgDM),研究DCAB对高温环境中奶牛生产性能和血清生化特性的影响。结果表明:(1)DCAB显著影响泌乳奶牛的血气指标,与对照组相比B组和C组血清的pH值显著增加(P<0.05)。血液中的HCO3-浓度和CO2总量)随着DCAB的增加而显著降低(P<0.05)。血液中的)随着DCAB的增加而显著增加。血液中的CO2分压(PCO2(TCO2)随着DCAB的增加而增加(P<0.05)。(2)血清中雌激素(E2)的浓度随着DCAB的)和O2饱和度(SATO2O2分压(PO2增加而显著增加。血清中的肌酸磷酸激酶(CK)随着DCAB的增加而降低,与对照组相比B组和C组奶牛血清中的CK分别降低了29.1%(P<0.01)和25.2%(P<0.01)。血清中的碱性磷酸酶(ALP)和谷丙转氨酶(GTP)受DCAB影响不显著。(3)DCAB对热应激奶牛的生产性能具有显著影响。275meq/kgDM组的产奶量及4%标准乳产量分别比对照组提高10%(P<0.05)和10.1%(P<0.05)。DCAB对奶牛的乳脂率和乳蛋白率无显著影响。从对血液缓冲能力、激素和酶水平及生产性能等方面考虑,在泌乳前期当DCAB为275meq/kgDM时饲喂效果最佳。

15 cows in early lactation were selected respectively in a replicated 3×3 Latin square design,and were assigned randomly into 3 groups, each with 5 replicates to study the effects of dietary cation-anion balance(DCAB) on performance and blood biochemical parameters of them in hot enviroment.Treatments involved the control group A(basal diet:with a DCAB of 83 meq/kg DM),B(with a DCAB of 275 meq/kg DM),C(with a DCAB of 325 meq/kg DM).The main results showed as follows:(1)DCAB remarkably influenced the blood gas parameters.The blood pH of B and C groups increased significantly compared with the control group (P<0.05) .Increased DCAB caused a increase in HCO_3^- and total CO_2(T_(CO_2)) concentrations in blood.Increased DCAB reduced partial pressure of carbon dioxide(P_(CO_2)) in blood significantly(P<0.05).Partial pressure of oxygen(P_(O_2)) and oxygen saturation(SAT_(O_2)) concentrations in blood increased with increased DCAB.(2)Blood serum estradiol(E_2) concentration increased linearly with increased DCAB.Increased DCAB decreased creatine kinase(CK) in serum significantly.Increased DCAB had no significant effects on alkaline phosphatase(ALP) and glutamic-pyruvic transaminase enzyme(GTP) in serum.(3)Increased DCAB affected production performance significantly.The milk yield and 4% fat corrected milk yield of 275 meq/kgDM group increased 10%(P<0.05)and 10.1%(P<0.05) compared with the control group respectively.Increased DCAB had no significant effects on milk fat percentage and milk protein percentage.As blood buffer capacity,hormone and enzyme of blood serum were concerned,the diet with a DCAB of 275 meq/kgDM in early lactation had the best effect.