Department of Population Medicine, University of Guelph, Guelph, ON, N1G 2W1, Canada.
Department of Population Medicine, University of Guelph, Guelph, ON, N1G 2W1, Canada.
Theriogenology. 2020 Jul 1;150:193-200. doi: 10.1016/j.theriogenology.2020.01.042. Epub 2020 Jan 20.
There is a high risk of clinical or subclinical reproductive tract disease in the postpartum period in dairy cows. An integrated process of adaptive events should occur synchronously, including a robust but well-regulated immune response in the uterus. Failure of this process may result in reproductive tract inflammatory disease. Up to half of postpartum dairy cows are affected by metritis, purulent vaginal discharge (PVD), or subclinical endometritis. After parturition there is damage to the birth canal, the superficial layer of the endometrium is naturally wounded, and essentially all dairy cows have bacterial contamination in the uterus. Neutrophils are the most abundant type of inflammatory cell and the main line of defence against infection in the uterus. A prompt influx of neutrophils is associated with uterine health. Avoidance of clinical disease (metritis and PVD) depends in large part on how effective the immune response is at limiting the burden and effects of bacterial pathogens, while the occurrence of subclinical endometritis is more a function of avoiding excessive or persistent inflammation. Glucose supply, hypocalcemia, lipid mobilization from body fat, ketosis, and the flux of pro-inflammatory cytokines influence immune response and change rapidly and variably among individual cows. Effective but well-regulated inflammatory response will be favoured by best management practices for transition cows, but specific interventions to modulate immune response to prevent uterine disease remain developmental.
奶牛产后的生殖道疾病存在较高的临床或亚临床风险。适应性事件的综合过程应该同步发生，包括子宫内强大但受调控的免疫反应。该过程的失败可能导致生殖道炎症性疾病。高达一半的产后奶牛会受到子宫炎、脓性阴道分泌物（PVD）或亚临床子宫内膜炎的影响。分娩后生殖道会受损，子宫内膜的浅层会自然受伤，而且基本上所有奶牛的子宫内都会有细菌污染。中性粒细胞是最丰富的炎症细胞类型，是子宫抗感染的主要防线。中性粒细胞的迅速涌入与子宫健康有关。避免临床疾病（子宫炎和 PVD）在很大程度上取决于免疫反应在限制细菌病原体的负担和影响方面的有效性，而亚临床子宫内膜炎的发生更多地取决于避免过度或持续的炎症。葡萄糖供应、低钙血症、体脂肪的脂动员、酮病和促炎细胞因子的流动都会影响免疫反应，而且在个体奶牛之间变化迅速且各不相同。过渡奶牛的最佳管理实践有利于产生有效的但受调控的炎症反应，但调节免疫反应以预防子宫疾病的具体干预措施仍在开发中。
