血液能量平衡指标对高产奶牛产后卵巢静止的影响

Effect of energy balance index on postpartum inactive ovary in high-producing dairy cows

本试验旨在确立能量平衡对奶牛产后卵巢静止的作用，为今后预防该病提供科学依据。从黑龙江省某集约化牛场随机选取产后14～21d奶牛80头（年龄2～4岁，胎次1～3次，泌乳量（34．82±9．51）kg／d），跟踪观测至产后60～90d，进行奶牛发情鉴定，结合B超观察与生殖激素检测从观测奶牛中选出卵巢静止与发情奶牛各16头。对2组奶牛产后14～21d和60～90d的血浆能量代谢及肝功能指标进行了统计比较。结果显示：产后60～90d卵巢静止奶牛血浆8-羟丁酸和游离脂肪酸含量高于发情奶牛（P〈0．05），血浆促卵泡素、雌二醇和孕酮浓度极显著低于发情奶牛（P〈0．01）；根据受试者工作特征曲线分析确定产后14～21d血浆β-羟丁酸〉0．69mmol／L、游离脂肪酸〉0．52mmol／L作为产后卵巢静止预警值，灵敏度和特异度分别为85．7％和83．30％，92．3％和86．70％，产后60～90d2项指标的预警值分别为0．42，0．17mmol／L。奶牛产后14～21d与60～90d血浆β-羟丁酸和游离脂肪酸浓度超过预警值，奶牛产后发生卵巢静止的风险会增大。

The objective of this study was to determine the role of energy balance in postpartum in- active ovary of the high-producing dairy cows, to provide a scientific basis for prevention of post- partum inactive ovary in the future. This experiment was conducted in an intensive dairy farm in Heilongjiang province. The experimental cows,2 to 4 years,1 to 3 parities,and milk（34.82±9.51） kg per day,were randomly selected at 14 d to 21 d postpartum and tracked until 60 to 90 d post- partum. The cows were assigned into two groups according to estrus diagnosis,B-scan images and concentration of the reproductive hormones, that is the inactive ovary group（T,n= 16）, and the healthy control group（C,n= 16）. Some parameters of energy balance and liver function were sta- tistically analyzed at 14 to 21 d and 60 to 90 d postpartum in two groups of cows. Results showed that plasma concentration of BHBA and NEFA in T group was significantly higher than that in C group. Plasma concentration of FSH,Ez and P4in T group was very significantly lower than that in C group. According to ROC analysis,risk prediction thresholds of inactive ovary at 14 to 21 d post- partum were more than 0.69 mmol/L for BHBA with 85.70/oo sensitivity and 92.3% specificity, and more than 0.52 mmol/L for NEFA with 83.3% sensitivity and 86. 7% specificity;at 60 to 90 d postpartum,the thresholds were more than 0.42 mmol/L for BHBA and 0. 17 mmol/L for NEFA. The results indicated that when plasma concentrations of BHBA and NEFA were over the thresholds at 14 to 21 d and at 60 to 90 d postpartum,the cows would get an increased risk of post- partum inactive ovary in high-producing cows.