Hormonal Milieu Around Parturition in Buffaloes (Bubalus bubalis)1

Radioimmunological measurements of prostaglandin F2 alpha, 13,14-dihydro-15-keto-PGF2 alpha (PGFM), estradiol-17 beta, progesterone, prolactin and luteinizing hormone (LH) were carried out in peripheral plasma around parturition in Murrah buffaloes. The PGF2 alpha concentration fluctuated before parturition and a peak was observed 1 day prior to parturition. PGFM, estradiol-17 beta and prolactin concentration increased gradually over the last 7 days with a significant peak (P less than 0.001) 1 day before parturition. The progesterone level declined gradually and an abrupt fall occurred 1-2 days before parturition. The estradiol-17 beta and prolactin concentrations declined to basal concentrations 1-2 days post partum, whereas PGF2 alpha and PGFM remained higher than basal concentrations. The LH concentration remained low without any significant variation. The progesterone concentration was negatively correlated with PGF2 alpha (r = 0.7039; P less than 0.05), PGFM (r = -0.8322; P less than 0.01) and estradiol-17 beta (r = -0.8896; P less than 0.001) before parturition.