本研究旨在评估细胞学子宫内膜炎(CYTO)的发生,子宫内膜的无症状炎症,第一次人工授精(AI)在挪威红牛产后。Further,评估了CYTO表现的危险因素及其对生殖成功和晚期胚胎丢失的影响。该研究共纳入了位于116群的1,648头母牛。主要是自发发情,子宫内膜细胞学样本采用细胞显像技术收集,在400倍放大倍数下计数总共300个代表性上皮细胞和多形核中性粒细胞(PMN)。记录通过Metricheck(Simcro)获得的阴道粘液和身体状况评分。在AI和21d后收集用于孕酮分析的牛奶样品。通过直肠触诊或妊娠相关糖蛋白分析诊断妊娠。基于接收者操作员特征曲线的构造,定义为CYTO的PMN的截止水平设置为3.0%,代表PMN发生影响妊娠结局的水平,敏感性(32.4%)和特异性(74.9%)的总和最高。建立了三个以羊群为随机因素的Logistic模型。第一个模型的结果是基于子宫内膜样本的CYTO的可能性,在第二次模型怀孕到第一次人工智能,在第三个模型胚胎丢失中。CYTO比例为28.0%(461/1,648)。首次AI的平均天数为71.7d(标准误差±0.7),首次AI的总体妊娠发生率为59.8%(866/1,449)。CYTO最初人工智能的可能性与人工智能人员有关,产卵到第一个AI间隔,阴道粘液的特点,样本中红细胞的数量,季节,和谷仓类型。CYTO阳性母牛的妊娠至第一次AI较低(比值比=1.51,置信区间=1.17-1.94)。影响第一次人工智能怀孕的其他因素是人工智能人员,测试日产奶量,谷仓类型,和第一次人工智能之前的产科条件或生育治疗。晚期胚胎丢失和流产的比例为8.6%(82/948)和2.8%(24/866),分别。晚期胚胎丢失与首次AI之前对生育障碍的治疗有关,但与CYTO无关。总的来说,我们的结果表明,即使挪威红牛在第一次AI时在子宫内膜中表现出相当高的CYTO患病率,它似乎对生殖性能没有重大影响。挪威红色育种计划几十年来一直强调生育和健康,遗传上有利的子宫免疫学可能是保留的机制之一。
The present study aimed to assess the occurrence of cytological endometritis (CYTO), a nonsymptomatic inflammation of the endometrium, at first artificial insemination (AI) postpartum in Norwegian Red cows. Further, risk factors for CYTO manifestation and its effect on reproductive success and late embryo loss were evaluated. In total 1,648 cows located in 116 herds were included in the study. On mainly spontaneous estrus, endometrial cytology samples were collected using a cytotape technique, and a total of 300 representative epithelial cells and polymorphonuclear neutrophils (PMN) were counted at 400× magnification. Vaginal mucus obtained by Metricheck (Simcro) and body condition score were recorded. Milk samples for progesterone analysis were collected at AI and 21 d later. Pregnancy was diagnosed by rectal palpation or analysis of pregnancy-associated glycoproteins. Based on the constructions of a receiver operator characteristics curve, the cut-off level for PMN defined as CYTO was set to 3.0%, representing the level at which the PMN occurrence affected pregnancy outcome, with the highest summation of sensitivity (32.4%) and specificity (74.9%). Three logistic models with herd included as random factor were constructed. The outcome for the first model was the likelihood for CYTO based on the endometrial samples, in the second model pregnancy to first AI, and in the third model embryo loss. The proportion of CYTO was 28.0% (461/1,648). The average interval in days to first AI was 71.7 d (standard error ± 0.7) and the overall pregnancy incidence to first AI was 59.8% (866/1,449). The likelihood for CYTO at first AI was associated with AI personnel, calving to first AI interval, vaginal mucus characteristics, amount of red blood cells in sample, season, and barn type. Pregnancy to first AI was lower in CYTO-positive cows (odds ratio = 1.51, confidence interval = 1.17-1.94). Other factors affecting pregnancy to first AI were AI personnel, test day milk yield, barn type, and obstetrical conditions or fertility treatments before first AI. The proportion of late embryo loss and abortion was 8.6% (82/948) and 2.8% (24/866), respectively. Late embryo loss was associated with treatment against fertility disorders before first AI, but not associated with CYTO. Overall, our results suggest that even if Norwegian Red cows show a fairly high prevalence of CYTO in the endometrium at first AI, it does not seem to have a major effect on the reproductive performance. The Norwegian Red breeding program has emphasized fertility and health for decades, and a genetically advantageous uterine immunology might be one of the preserved mechanisms.