中文摘要：

试验旨在研究不同日粮阴阳离子差（DCAD）对喀斯特地区围产期奶牛体内代谢、健康状况及泌乳性能的影响。将30头荷斯坦经产干奶牛按照随机区组设计分为3组：对照组、试验1组和试验2组,其DCAD水平分别为＋81、＋20和-32 mmol.kg-1DM。结果表明：尿液pH随DCAD水平的降低而显著降低（P〈0.05）;试验2组血浆Ca、Cl水平显著高于对照组（P〈0.05）;血浆Na、K、P,葡萄糖、尿素氮浓度差异不显著（P〉0.05）;试验1组和试验2组低血钙、胎衣不下发生率较对照组低;各组奶牛对DMI、奶产量和奶成分影响不大（P〉0.05）。结果提示,在喀斯特地区围产期奶牛日粮中添加阴离子盐是可行的,可引起奶牛体内代偿性轻度代谢酸中毒,增加血Ca水平,有利于改善健康状况,对奶牛产后泌乳性能影响不大。

英文摘要：

The objective of this study was to evaluate the body metabolism,health status and subsequent lactation performance of periparturient cows fed diets with varying cation-anion difference（DCAD） in Karst area.Thirty Holstein multiparious cows were randomly assigned to 3 blocks of 10 cows and were fed 1 of 3 diets with DCAD at ＋81,＋20,and-32 mmol·kg-1 DM for control,treatment 1 and treatment 2,respectively.The results showed that feeding of lower DCAD reduced urine pH among 3 DCAD treatments（P0.05）.Plasma Ca and Cl levels were higher in treatment 2（P0.05） compared with control.Dietary treatments did not alter plasma Na,K,and P,and glucose and urea nitrogen concentrations（P0.05）.Cows fed treatment 1 and treatment 2 had lower incidence of hypocalcemia and retained placenta over those fed control.Dry matter intake,milk yield and compositions were unaffected by dietary treatment（P0.05）.It is suggested that anionic salts supplementation in the dry-off diet for cows in Karst area is appropriate which may lead to mild metabolic acidosis,increase blood Ca level and improve health status,with non-significant impact on lactation performance.