Wischral A, Verreschi I T, Lima S B, Hayashi L F, Barnabe R C
Department of Veterinary Medicine, Universidade Federal Rural de Pernambuco, Rua Manoel de Medeiros, S/N, 52171-900, Dois Irmaos, Recife, Pernambuco, Brazil.
Anim Reprod Sci. 2001 Sep 15;67(3-4):181-8. doi: 10.1016/s0378-4320(01)00119-1.
Retained foetal membranes in cattle is one of the most common complications associated to the reduction in milk yield and impaired fertility in dairy cattle. In order to determine some endocrine mechanisms controlling parturition and delivery of foetal membranes, plasma concentrations of steroids and prostanoids were determined in 20 healthy Holstein cows. Samples were taken within the interval of 5 days pre-parturition to 12h after calving. Progesterone (P4) levels were similar in cows with (PR) and without (NPR) placental retention. While the estradiol-17beta (E2) peak at parturition was lower in PR than in NPR cows, cortisol levels were greater in PR cows 12 and 24h pre-parturition. The Prostaglandin F2alpha metabolite (PGFM) levels were higher at parturition in NPR compared with the PR group, but 12h later, these levels in the PR group increased so that concentrations were greater as compared with NPR cows. The Prostaglandin E2 metabolite (PGEM), 24, 48 and 72 h pre-parturition, were higher in PR cows. However, the PGFM:PGEM ratio was greater in cows up NPR at all time when included, indicating the importance of higher levels of Prostaglandin F2alpha (PGF2alpha) than Prostaglandin E2 (PGE2) for normal placental delivery. In conclusion, placental retention was related to both estrogen and PGF2alpha deficiency, which may be a consequence of metabolic stress leading to PGE2 and maternal cortisol synthesis before parturition.
奶牛胎膜残留是与产奶量下降和繁殖力受损相关的最常见并发症之一。为了确定一些控制分娩和胎膜排出的内分泌机制，对20头健康的荷斯坦奶牛测定了类固醇和前列腺素的血浆浓度。在分娩前5天至产后12小时的时间段内采集样本。有胎盘残留（PR）和无胎盘残留（NPR）的奶牛孕酮（P4）水平相似。虽然PR奶牛分娩时的雌二醇-17β（E2）峰值低于NPR奶牛，但PR奶牛在分娩前12小时和24小时的皮质醇水平更高。与PR组相比，NPR组分娩时前列腺素F2α代谢物（PGFM）水平更高，但12小时后，PR组的这些水平升高，因此与NPR奶牛相比浓度更高。PR奶牛在分娩前24、48和72小时的前列腺素E2代谢物（PGEM）水平更高。然而，在纳入的所有时间点，NPR奶牛的PGFM:PGEM比值更高，表明较高水平的前列腺素F2α（PGF2α）比前列腺素E2（PGE2）对正常胎盘排出更为重要。总之，胎盘残留与雌激素和PGF2α缺乏有关，这可能是分娩前代谢应激导致PGE2和母体皮质醇合成的结果。
