奶牛亚临床酮症的研究进展

Research Advances on Subclinical Ketosis in Dairy Cows

酮症是高产奶牛在泌乳前期的常见病。根据有无临床症状将酮症分为临床酮症(clinical ketosis,CK)和亚临床酮症(subclinical ketosis,SCK)。酮症会导致奶牛血液或牛奶中酮体浓度增加,目前主要通过检测血液中β-羟丁酸(BHBA)浓度高低来对酮症进行诊断。CK对奶牛的影响比较明显,因此更能引起牧场主的关注。而奶牛患有SCK后不表现出临床症状,往往容易被牧场主忽视。SCK如同CK和奶牛围产期其他疾病一样是造成奶牛经济和福利损失的主要原因之一。SCK大大增加了奶牛产后相关疾病的风险,如CK、真胃移位、胎衣不下、乳房炎和子宫炎等,另外患有SCK的奶牛生产性能大幅度下降(泌乳性能降低、繁殖性能变差、淘汰率增加),给牧场的发展带来了不可估量的损失。SCK可能在未被发现的时候就已经开始对生产性能产生影响,而且它对生产性能的影响与CK引起的影响相当,但是由于缺乏临床症状而不被牧场重视。作者在这篇综述中将着重介绍奶牛SCK的最新研究进展,这不仅有助于进一步了解奶牛酮症的发病机理及SCK对生产力的不利影响,并且可提供针对SCK的不同检测方法和可行的预测方法来帮助牧场进行早期诊断,减少因SCK造成的奶牛福利和经济损失。

Ketosis is a common disease of high-yield cows in early lactation,and classified as clinical ketosis(CK)and subclinical ketosis(SCK)by the clinical symptoms.Ketosis results in an increase ofβ-hydroxybutyric acid(BHBA)levels in blood and milk.At present,blood BHBA levels are used for the diagnosis of ketosis.CK has a significant impact on the performance of cows,so it attracts the attention of farmers.However,the symptoms of cows suffering from SCK are not obvious and often overlooked by farmers.Like CK and other transition diseases,SCK is also one of the main causes of economic and welfare losses in dairy cows.SCK increases the risk of production-related disorders,such as clinical ketosis,displacement abomasum,retained placenta,lameness,mastitis,and metritis,while reduced animal performance(lower milk production,poor reproductive performance,increased cull rates).SCK may start to affect production even before it is detected,causing huge financial losses in the dairy industry.Notably,the financial losses caused by SCK are more than CK,which are always underestimated by farmers.This review highlights the latest research advances in SCK in dairy cows,which will provide insight into the pathogenesis of ketosis and the adverse effects of SCK on productivity in dairy cows.In addition,early detection and prediction of SCK is presented to decrease the loss of animal welfare and the economy in dairy industry.