Department of Clinical Sciences, Faculty of Veterinary Medicine, Shahid Bahonar University of Kerman, Kerman, Iran.
College of Veterinary Medicine, Oklahoma State University, Stillwater, OK, USA.
Theriogenology. 2021 Apr 1;164:36-41. doi: 10.1016/j.theriogenology.2021.01.016. Epub 2021 Jan 27.
Previous observational studies have produced strong evidence that metritis alone has an impact on reproductive performance in dairy cows; but few studies have examined the combined effect of metritis and other postpartum diseases on reproduction performance in dairy cows. Information on the combined effects of postpartum diseases on fertility in dairy cows can have practical herd-health management implications. The objective of the study reported here was to examine the observed and expected combined effects of metritis and other postpartum diseases (retained fetal membranes (RFM), clinical hypocalcemia, left displaced abomasum, clinical mastitis, lameness) on time to conception and rate of conception failure in first-lactation cows up to 150 days postpartum. The study was conducted on two commercial dairy herds in Iran. Median number of days to conception was higher in 30 cows affected with metritis and RFM (90 days), compared to 287 healthy cows (57 days), 16 cows affected with RFM alone (60 days) or 44 cows affected with metritis alone (60 days), after controlling for herd and calving month (p < 0.05). In cows affected with metritis and RFM, the rate of conception failure was 3.8 times greater than that of healthy cows, after controlling for study herd and calving month (hazard ratio = 3.8; 95% CI = 2.3, 6.6; p < 0.01); this observed combined effect on conception failure was two times higher than the expected combined effect based on adding or multiplying absolute independent excesses due to metritis or RFM. In addition, we observed an interaction effect between metritis and lameness on conception failure, after controlling for herd, calving month, and RFM; but study results were inconclusive. In this study, the observed combined effect of metritis and RFM on time to conception and rate of conception failure was far in excess, compared to that in cows exposed to metritis or RFM alone. Attending veterinarians or farm managers can consider this information when making breeding and culling decisions on dairy farms.
先前的观察性研究已经提供了强有力的证据，表明单纯的子宫炎会对奶牛的繁殖性能产生影响；但很少有研究探讨子宫炎和其他产后疾病对奶牛繁殖性能的综合影响。关于产后疾病对奶牛繁殖力综合影响的信息对牧场的健康管理具有实际意义。本报告研究的目的是检验子宫炎和其他产后疾病（胎衣不下（RFM）、临床低血钙症、真胃左方变位、临床乳腺炎、跛行）对初产奶牛产后 150 天内配种时间和配种失败率的观察到的和预期的综合影响。该研究在伊朗的两个商业奶牛场进行。在控制了牛群和产犊月份后，患有子宫炎和 RFM 的 30 头牛（90 天）的配种时间中位数高于 287 头健康牛（57 天）、16 头仅患有 RFM 的牛（60 天）或 44 头仅患有子宫炎的牛（60 天）（p < 0.05）。在患有子宫炎和 RFM 的奶牛中，在控制了研究牛群和产犊月份后，配种失败率是健康奶牛的 3.8 倍（风险比=3.8；95%置信区间=2.3，6.6；p < 0.01）；这种观察到的对配种失败的综合影响比基于添加或乘以子宫炎或 RFM 的绝对超额独立过剩的预期综合影响高两倍。此外，我们在控制了牛群、产犊月份和 RFM 后，观察到子宫炎和跛行对配种失败的交互作用，但研究结果尚无定论。在本研究中，与单独接触子宫炎或 RFM 的奶牛相比，子宫炎和 RFM 对配种时间和配种失败率的观察到的综合影响要大得多。在做出奶牛场的繁殖和淘汰决策时，兽医或农场经理可以考虑这些信息。
