The causes of low fertility in dairy cattle are complex and multifactorial and may be due to compromised follicle development affecting oocyte quality, a suboptimal reproductive tract environment incapable of supporting normal embryo development, or a combination of both. Progesterone (P4) plays a key role in reproductive events associated with establishment and maintenance of pregnancy, through its effects on oocyte quality and its action on the uterine endometrium. Reduced P4 concentrations during growth of the ovulatory follicle are associated with lower fertility, and low concentrations of circulating P4 after ovulation have been associated with reductions in conceptus growth and elongation, decreased interferon-τ (IFNT) production, and lower pregnancy rates in cattle. In contrast, elevated concentrations of circulating P4 in the period immediately following conception have been associated with advancement of conceptus elongation, increased IFNT production, and, in some cases, higher pregnancy rates in cattle. Despite the potential beneficial effects of exogenous P4 supplementation on fertility, results of supplementation studies have been inconsistent. As part of the 2019 ADSA Reproduction Symposium, focusing on the etiology of pregnancy losses in dairy cattle, the aim of this review is to highlight recent findings from our group and others in relation to embryo-maternal interaction during bovine pregnancy establishment and the role of P4 in uterine biology and embryo development.

奶牛低生育力的原因是复杂的和多因素的，并且可能是由于卵泡发育受损而影响了卵母细胞的质量，不能支持正常胚胎发育的次优生殖道环境或两者的结合。孕酮（P4）通过对卵母细胞质量的影响及其对子宫内膜的作用，在与妊娠的建立和维持有关的生殖事件中起关键作用。排卵卵泡生长过程中P4浓度降低与生育能力降低有关，排卵后循环P4浓度低与观念发育和伸长减少，干扰素-τ（IFNT）产生减少以及牛的妊娠率降低有关。相反，受孕后立即升高循环中的P4浓度与延长受孕时间，增加IFNτ的产生以及在某些情况下牛的高妊娠率有关。尽管外源P4补充对生育有潜在的有益影响，但补充研究的结果却不一致。作为2019年ADSA繁殖专题讨论会的一部分，重点关注奶牛妊娠损失的病因学，本综述的目的是强调我们小组和其他研究人员最近关于牛妊娠建立过程中胚胎与母体相互作用以及胎粪的作用的发现。 P4在子宫生物学和胚胎发育中。牛的怀孕率更高。尽管外源P4补充对生育有潜在的有益影响，但补充研究的结果却不一致。作为2019年ADSA繁殖专题讨论会的一部分，重点关注奶牛妊娠损失的病因学，本综述的目的是强调我们小组和其他研究人员最近关于牛妊娠建立过程中胚胎与母体相互作用以及胎粪的作用的发现。 P4在子宫生物学和胚胎发育中。牛的怀孕率更高。尽管外源P4补充对生育有潜在的有益影响，但补充研究的结果却不一致。作为2019年ADSA繁殖专题讨论会的一部分，重点关注奶牛妊娠损失的病因学，本综述的目的是强调我们小组和其他研究人员最近关于牛妊娠建立过程中胚胎与母体相互作用以及胎粪的作用的发现。 P4在子宫生物学和胚胎发育中。