奶牛亚临床酮病对乳房炎发病情况和抗氧化功能的影响

The Influence of sub-clinical ketosis on the incidence and pathogen of mastitis in dairy cows

为研究奶牛亚临床酮病与乳房炎的关系以及血液中的酮体成分对奶牛抗氧化功能的影响,以156头健康荷斯坦奶牛为试验动物(SCC<200 000/mL),共筛选亚临床酮病奶牛69头(1.0 mmol/L≤BHBA<2.6 mmol/L)作为试验组,根据年龄、胎次、产奶量、泌乳天数配对的69头奶牛作为对照组(血液BHBA<1.0 mmol/L),监测乳房炎发病情况并在各组中选取12头奶牛检测血液酮体水平和抗氧化指标。结果表明亚临床酮病奶牛试验期间乳房炎的发病率为43.48%,对照组试验期间乳房炎的发病率为31.88%,但差异不显著(P>0.05);试验组奶牛乳房炎高发期为分娩后3～6周,对照组奶牛乳房炎发病时间为分娩后5～8周,亚临床酮病发病后1～3周内为乳房炎的高发期,占试验组奶牛乳房炎总发病比例的73.33%,试验组和对照组病原菌的组成无显著差异(P>0.05);试验组奶牛血液中T-AOC显著低于对照组(P<0.05),GSH-PX活力、MDA和NO显著高于对照组(P<0.05),血液ACAC浓度与GSH-PX活力呈显著正相关(P<0.05,r=0.595),ACAC浓度与NO呈显著正相关(P<0.05,r=0.655),T-AOC与MDA呈显著负相关(P<0.05,r=0.533)。结果表明奶牛亚临床酮病可以导致乳房炎的发病率升高,但不是主要影响因素,亚临床酮病对乳房炎病原体构成无影响;外周血酮体水平升高导致机体总抗氧化能力的降低并引起机体脂质过氧化反应;谷胱甘肽过氧化物酶在发挥抗氧化功能时具有一定的抵抗力和自我调节能力。

Abstract：In order to find the relationship between subclinical ketosis and mastitis and check the influence of the ketone body on antioxidant. The experimental animals were 156 Holstein cows （SCC（200 000/mL）which deliveryed within 7 weeks. There were 69 subclinical ketosis cows（1.0 mmol/L≤serum BHBA（2. 6 mmol/L）in the test group. The control group was corresponding to the test group according to age, parity,milk yield and days in milk （serum BHBA（1.0 mmol/L）. The incidence of mastitis and the variety of mastitis pathogen were recorded. Twelve cows from each group were tested for ketone bodies and antioxidant. The result indicated that the incidence of masti- tis in the test group was 43. 48% ,while the control group was 31.88%. But the difference was not significant. Mastitis of test group mainly occurred during the third to sixth week after parturition, while the control group mainly occurred during fifth to eighth week after parturition. Occurrence of mastitis delayed one to three weeks later compared with subclinical ketosis,and 73.33% occurred three weeks after parturition. There was no different in the construction of the mastitis pathogen（P〉0.05）. The level of T-AOC in the serum of test group was significantly lower than the control group（P〈0.05）. But the levels of GSH-PX, MDA and NO in the serum of test group was significantly higher than the control group（P〈0.05）. The correlation of ACAC and GSH-PX was significant positive（P〈0.05）. There was also a significant positive correlation between ACAC and NO level（P〈0.05）. The correlation of T-AOC and MDA showed significant negative（P〈0.05）. The result shows that subclinical ketosis can cause mastitis but not a major factor. Blood ketone bodies may influence the antioxidant and lead to oxidative stress in dairy cows. There were resistance and self-regulation capability of the GSH-PX playing an antioxidant function.