Peripartal changes of estrone, progesterone and prostaglandin in the water buffalo

The peripheral blood plasma concentration of estrone, progesterone and 15-keto-13, 14-dihydroprostaglandin F2alpha (PGF2alpha metabolite) were determined by radioimmunoassay techniques during the peripartal period in 5 buffalo cows belonging to a river type breed. Estrone levels started to increase from below 200 pg/ml about 15 days prior to parturition, and reached high concentrations (400-750 pg/ml) during the last 5 days of pregnancy. The estrone concentration decreased to baseline levels after delivery. The concentration of progesterone fluctuated between 800 and 2000 pg/ml until 15 days before calving and showed a gradual increase during the last 15 days of pregnancy. The progesterone levels declined abruptly on the day of calving and remained below 100 pg/ml for up to 60 days post-partum. Increased levels of the prostaglandin metabolite were recorded from 15 days prior to parturition with further increases occurring during the last 3 days of pregnancy. PGF2alpha metabolite levels declined gradually after parturition, reaching base line levels 15-20 days after calving.