奶牛酮病早期预警指标的确立与评估

Establishment and Evaluation of Early Prediction Warning on Ketosis in Dairy Cows

为了早期预测奶牛酮病的发生，在黑龙江省东、西部2个集约化牛场（均有250多头泌乳牛）随机选取产前15—2d，分娩当天，产后2—15d的奶牛为试验动物。通过检测试验牛血浆中葡萄糖（Glu）、β-羟丁酸（BHBA）和游离脂肪酸（NEFA）的浓度，了解产后奶牛酮病发生状况；通过检测试验牛产前和产后各肝功指标，阐明奶牛围产期肝功指标与酮病间的关系以及对产后酮病发生风险的预警作用。结果表明：酮病发病率在东部牧场为40％，在西部牧场为45．16％；两牧场产后奶牛的血浆谷草转氨酶（AST）、NEFA和BHBA的水平均显著高于产前奶牛并与酮病呈显著正相关，血浆Glu水平显著低于产前奶牛并与酮病呈显著的负相关。根据受试者工作特征曲线（ROC）分析确定了东部牧场的预警值为产前血浆AST〉69．5U／L、G1u〈4．16mmol／L、NEFA〉0．25mmol／L、BHBA〉0．32mmol／L。西部牧场预警值为血浆AST〉68．0U／L、Glu〈3．97mmol／L、NEFA〉0．27mmol／L、BHBA〉0．43mmol／L。结果显示，奶牛产前血浆NEFA、Glu、AST和BHBA指标超过预警值可作为奶牛发生酮病的早期风险预测依据。

To predict early the occurrence of ketosis in dairy cow, the test was conducted in two intensive dairy farms that owned more than 250 lactating cows. All tested cows were randomly selected at d 15 to d 2 prepartum, parturition, and d 2 to d 15 postpartum in East and West Farm. Plasma concentration of Glu, BHBA and NEFA was detected to assess the prevalence of ketosis. TP, ALB, GLO, ALT, AST, and CHE in plasma were determined to reveal the relationship between ketosis and liver functions and its early warning effect on ketosis. The results showed that the incidence of ketosis in East herd was 40.00% and in West herd was 45.16%. The concentration of BHBA, NEFA and AST in plasma from cows postpartum was significantly higher than those of cows prepartum and a significantly positive correlation between plasma concentration of BHBA, NEFA and AST and ketosis. Plasma concentration of glucose was significantly lower after calving in two herds and a significantly negative correlation between plasma Glu concentration and ketosis. According to ROC analysis, risk prediction thresholds of ketosis in East herd were 〉69.5 U/L for AST, 〈4.16 mmol/L for Glu, 〉0.25 mmol/L for NEFA, 〉0.32 mmol/L for BHBA. Of in West herd were 〉68.0 U/L for AST, 〈3.97 mmol/L for Glu, 〉0.27 mmol/L for NEFA, 〉0.40 mmol/L for BHBA. Conclusions obtained that plasma concentration of BHBA, NEFA, Glu and AST over thresholds before parturition could be considered as early risk prediction warning basis of ketosis.