Croushore William S, Ospina Paula A, Welch David C, Zawisza Daniel J, Nydam Daryl V
White Oak Veterinary Clinic, PC, 7631 Glades Pike, Berlin, PA 15530.
J Am Vet Med Assoc. 2013 Nov 1;243(9):1329-33. doi: 10.2460/javma.243.9.1329.
To estimate the sensitivity, specificity, likelihood ratios, and predictive values of blood β-hydroxybutyrate (BHB) concentrations in dairy cows immediately prior to surgical correction of left-displaced abomasum (LDA) for determining associations between BHB concentration and removal from the herd ≤ 30 days after surgery and to evaluate postsurgical risk of removal for cows with the BHB concentration that had highest sensitivity and specificity for predicting this outcome.
Prospective cohort study.
136 dairy cows with LDA diagnosed between 5 and 30 days in lactation (ie, days in milk).
Blood BHB concentration was measured immediately prior to surgery. All cows underwent surgical correction of LDA while standing. Follow-up information was obtained ≥ 30 days after surgery. Receiver operating characteristic curves were used to estimate a critical threshold value for BHB concentration that was associated with removal from the herd, and this value was used in Poisson regression to estimate risk ratio for the same outcome.
While controlling for parity in the model, cows with a BHB concentration < 1.2 mmol/L at the time of LDA surgery were 2.5 times as likely (95% confidence interval, 1.3 to 5.0) to be removed from the herd ≤ 30 days after surgery, compared with cows that had a BHB concentration ≥ 1.2 mmol/L.
Results indicated that blood BHB concentration in dairy cows undergoing surgical correction of LDA may potentially be a useful prognostic indicator for the likelihood of removal from the herd ≤ 30 days after surgery. Further research is needed to evaluate other risk factors that may be associated with this outcome.
评估在对左方变位真胃（LDA）进行手术矫正前，奶牛血液中β-羟基丁酸（BHB）浓度的敏感性、特异性、似然比和预测值，以确定BHB浓度与术后≤30天内从牛群中淘汰之间的关联，并评估对于预测该结果具有最高敏感性和特异性的BHB浓度的奶牛术后淘汰风险。
前瞻性队列研究。
136头在泌乳5至30天（即产奶天数）被诊断为LDA的奶牛。
在手术前立即测量血液BHB浓度。所有奶牛均在站立状态下接受LDA手术矫正。术后≥30天获取随访信息。采用受试者工作特征曲线来估计与从牛群中淘汰相关的BHB浓度临界阈值，并将该值用于泊松回归以估计相同结果的风险比。
在模型中控制胎次的情况下，与BHB浓度≥1.2 mmol/L的奶牛相比，LDA手术时BHB浓度<1.2 mmol/L的奶牛在术后≤30天从牛群中被淘汰的可能性高2.5倍（95%置信区间，1.3至5.0）。
结果表明，接受LDA手术矫正的奶牛血液BHB浓度可能是术后≤30天从牛群中被淘汰可能性的一个有用的预后指标。需要进一步研究以评估可能与该结果相关的其他风险因素。
