Abstract
The incidence of retained fetal membranes (RFM) in Holstein cows from records of 1695 calvings in southern Osaka, and plasma levels of certain hormones and vitamins in cows calving during January and March were determined. The RFM incidence was significantly higher (P<0.02) in winter (January and February) and early summer (June and July) than in other seasons (spring and autumn). Daily changes in plasma concentrations of progesterone, estrone and estradiol were similar between two groups with RFM and without RFM (NRFM). Progesterone decreased from a few days before parturition, whereas estrone and estradiol increased from 10-6 days to 4 days before parturition, and decreased near parturition in both groups. While there was no difference between groups in changes in vitamin A, the RFM group had a lower level of β-carotene than the NRFM group near parturition. These results indicated that lower concentrations of plasma β-carotene were associated with the higher RFM incidence in dairy cows in winter.
