Veterinary Medicine School, Faculty of Agrarian Sciences, University of Antioquia. One Health Veterinary Research and Innovation - OHVRI Group. Calle 70 No. 52-21, Medellín, Colombia.
Veterinary Medicine School, Faculty of Agrarian Sciences, University of Antioquia. One Health Veterinary Research and Innovation - OHVRI Group. Calle 70 No. 52-21, Medellín, Colombia.
Prev Vet Med. 2020 Dec;185:105202. doi: 10.1016/j.prevetmed.2020.105202. Epub 2020 Nov 5.
Infertility is a common consequence of cows suffering from postpartum uterine diseases. Diseases from a uterine origin in early lactation affect both uterine and ovarian tissues decreasing the probability of pregnancy. The objective of the present study was to determine the impact of clinical metritis, clinical endometritis, and subclinical endometritis on days open in cows from high-altitude tropical dairy herds. A single cohort longitudinal study was conducted from January 2018 to February 2019, which included 248 cows enrolled from five commercial high-altitude tropical dairy herds in the northern region of the Department of Antioquia, Colombia. A directed acyclic graph was used to identify minimal sufficient adjustment sets for each exposure variable of interest. Based on the directed acyclic graph, three models (one for each of clinical metritis, clinical endometritis, and subclinical endometritis) were proposed to assess the impact of postpartum uterine diseases on days open. The time at risk was defined as the days elapsed from calving until pregnancy (event or censure). Observations were right-censored if cows were either culled, dead, were lost to follow up, suffered a systemic illness that required the use of parenteral drugs, or if they were not pregnant at 210 postpartum days. Three Cox proportional hazards models were proposed to estimate the Hazard Ratios (HR) at any point in the follow-up period for each exposure variable. The hazard of pregnancy was significantly lower for cows with metritis (40 %; HR = 0.60; 95 % CI: 0.43 - 0.86), clinical endometritis (69 %; HR = 0.31; 95 % CI: 0.22 - 0.45), and subclinical endometritis (76 %; HR = 0.24; 95 % CI: 0.16 - 0.36) compared to their herd mates without these conditions. These results provide evidence of the negative impact of postpartum uterine diseases on time to pregnancy in grazing lactating dairy cows from high-altitude tropical herds.
奶牛产后子宫疾病是导致其不孕的常见原因。初乳期由子宫引起的疾病会影响子宫和卵巢组织，降低受孕的可能性。本研究的目的是确定临床子宫炎、临床子宫内膜炎和亚临床子宫内膜炎对高海拔热带奶牛场奶牛开产天数的影响。本研究于 2018 年 1 月至 2019 年 2 月进行了一项单队列纵向研究，包括来自哥伦比亚安蒂奥基亚省北部五个商业高海拔热带奶牛场的 248 头奶牛。使用有向无环图来确定每个感兴趣暴露变量的最小充分调整集。基于有向无环图，提出了三个模型（一个用于临床子宫炎、临床子宫内膜炎和亚临床子宫内膜炎）来评估产后子宫疾病对开产天数的影响。风险时间定义为从产犊到怀孕（事件或截尾）的天数。如果奶牛被淘汰、死亡、失去随访、患有需要使用静脉注射药物的全身性疾病，或者在产后 210 天仍未怀孕，则观察结果将被右删失。提出了三个 Cox 比例风险模型来估计随访期间任何时间点每个暴露变量的风险比（HR）。患有子宫炎的奶牛怀孕的风险显著降低（40%；HR=0.60；95%CI：0.43-0.86），临床子宫内膜炎（69%；HR=0.31；95%CI：0.22-0.45）和亚临床子宫内膜炎（76%；HR=0.24；95%CI：0.16-0.36）与无这些疾病的同群奶牛相比。这些结果提供了证据，证明了产后子宫疾病对高海拔热带牧场放牧泌乳奶牛怀孕时间的负面影响。
