Levels of Prostaglandins and Angiotensin in Retained Placenta of Cattle

The aim of this study is to explore the endocrine mechanisms of placenta retention. Endocrine factors play a role in the manifestation of placenta retention in dairy cows. Prostaglandin E causes relaxation of smooth muscle in the non-pregnant uterus and uterus placenta angiotensin can regulate placenta prolactin release, regulate steroid and prostaglandin synthesis, modulate placenta blood pressure, stimulate uterine smooth muscle contraction. To investigate the relationship between placenta retention and placental prostaglandins and angiotensin, 10 cows did not release the fetal membranes within 12 h after parturition and served as the retained placenta group and 10 cows in that group which released their fetal membranes within 12 h, served as the health group. Levels of these endocrine factors in retained placenta were measured with ELISA and compared with those in normal placentas. Results showed that retained placenta had significantly lower levels of prostaglandins and angiotensin II (p<0.01). This observation suggests that the lower levels of Prostaglandins (PGE2) and angiotensin II may participate in the development of placenta retention.