低酸度酒精阳性乳奶牛血液及乳指标分析

Analysis of Milk and Blood Indexes from Cows with Low Acidity Alcohol Positive Milk

本试验旨在通过对低酸度酒精阳性乳奶牛的乳指标和血液指标分析,探究低酸度酒精阳性乳发生的原因,为低酸度酒精阳性乳的防控提供理论支持。选取内蒙古发生酒精阳性乳的某大型牧场,从平均泌乳天数(150~170d)、平均胎次(2~3胎)、平均日产奶量(30~35kg)相近的牛中,根据70%酒精测试和加州乳房炎测试(CMT)结果,挑选出酒精测试为阴性、CMT测试为阴性的牛只11头作为阴性组;酒精测试为阳性、CMT测试为阴性的11头牛只作为阳性组。随后对各组牛奶中的离子含量和肌酸激酶(CK)、乳酸脱氢酶(LDH)含量,奶牛血清中离子含量和抗氧化指标等进行检测。结果显示:阳性组牛只牛奶中的钾、镁、CK含量显著高于阴性组(P<0.05),阳性组牛只牛奶中的钙含量和pH值显著低于阴性组(P<0.05);阳性组牛只血清中的钾含量和MDA含量显著高于阴性组(P<0.05)。由此得出结论,在奶牛氧化应激的情况下,血液离子平衡发生变化、乳腺上皮细胞发生损伤,改变了乳腺上皮细胞对血液物质的吸收和代谢,导致牛奶中pH值降低,游离镁、钾的含量增加,从而降低了牛奶对酒精的稳定性。

The purpose of this experiment was to explore the causes of low acidity alcohol positive milk by studying the milk index and blood index analysis of cows with low acidity alcohol positive milk,and to provide theoretical support for the prevention and control of low acidity alcohol positive milk.In a large ranch with alcohol-positive milk in Inner Mongolia,cattle were selected according to the average lactation days(150~170d),average parity(2~3),average daily milk yield(30~35kg),70%alcohol test and California mastitis test(CMT).Finally,11 cows with negative alcohol test and negative CMT test were selected as the negative group,and 11 cows with positive alcohol test and negative CMT test were selected as the positive group.Then,the ion content and creatine kinase(CK)and lactate dehydrogenase(LDH)in milk were determined,and the serum ion content and antioxidant indexes were determined.Results showed that,the contents of potassium,magnesium and CK in milk in positive group were significantly higher than those in negative group(P<0.05),calcium content and pH value of cow milk in positive group were significantly lower than those in negative group(P<0.05);serum potassium content and MDA content in positive group were significantly higher than those in negative group(P<0.05).Oxidative stress affects the balance of blood ions,causes damage to mammary gland epithelial cells,and changes the absorption and metabolism of blood substances.This results in a decrease in the pH of the milk and an increase in the content of free magnesium and potassium,thus reducing the stability of the milk against alcohol.