乳牛产后血浆瘦素动态与亚临床酮病的相关分析

Analysis of relationship between dynamic changes of blood plasma leptin and occurrence of subclinical ketosis in dairy cows during parturition

对某奶牛场16头乳牛产前10d至产后56d血样的瘦素、酮体、葡萄糖、脂肪水平及其动态特征和相关性进行了检测。结果表明，血浆瘦素、血酮、血脂含量在不同乳牛和不同时间点之间均有显著差异。酮体在产后14～49d出现高峰，瘦素和血脂从产后第0d到产后第56d内逐渐升高。瘦素水平与血脂水平呈极显著正相关，血酮与血糖呈极显著负相关。亚临床酮病组乳牛的瘦素和血脂水平分别极显著或显著低于血酮正常组，其瘦素、血酮和血糖在试验期内的波动频率明显减少，跨度变长，瘦素在试验期内仅出现一个两端接近0、波峰不超过1．5ng／mL的波。证实，产后乳牛瘦素、血酮、血糖含量的低频率波动变化和产后8周内血浆瘦素跨时持久的单峰动态变化与乳牛亚临床酮病的发生有关。

Blood samples were collected from 16 cows on one dairy farm at 12 time points between day 10 before parturition and day 56 after parturition,and plasma concentrations and dynamic changes of leptin,ketone bodies, glucose and lipids, and correlation among them were analyzed. The concentrations of plasma glucose and lipids were determined by routine methods. There was significant difference in leptin, ketone bodies and lipids levels between cows and between time points. The leptin and lipids levels were gradually increased from day 0 or day 2 to day 56 postpartum,and there was a peak of ketone bodies level between day 14 and day 49. There was a significant positive correlation between leptin and lipids and a significant negative correlation between ketone bodies and glucose. The average levels of leptin and lipids were significantly lower in subclinical ketosis group than those in healthy group. The dynamic changes of leptin, ketone bodies and glucose in subclinical ketosis group displayed obviously lower frequency, longer span fluctuations than healthy cows, the leptin exhibited single wave with two sides near 0, and the peak was less than 1.5 ng/mL. It was concluded that both the low frequency changes of leptin, ketone bodies and glucose in cows postpartum and the occurrence of a single wave in leptin dynamic change within 8 weeks postpartum are associated with the development of subclinical ketosis.