Plasma concentrations of 13, 14-dihydro-15-keto-prostaglandin F2alpha, progesterone and cortisol during periparturient period in yaks (Poephagus grunniens L.).

An attempt was made to determine plasma concentrations of, 13, 14-dihydro-15-keto-prostaglandin F(2alpha) (PGFM), cortisol and progesterone during periparturient period in yak. Plasma PGFM level showed an increasing trend beginning day 5 prior to parturition (0.48 +/- 0.14 ng/ml) and increased steeply thereafter to reach a peak level (17.16 +/- 1.31 ng/ml) on the day of parturition. The levels, then, declined sharply on day 1 postpartum to reach 1.20 +/- 0.40 ng/ml and thereafter declined gradually over the days to reach 0.28 +/- 0.09 ng/ml on day 20 postpartum and this level was maintained with fluctuation within narrow limits thereafter till conclusion of the blood sampling on day 90 post-calving. The plasma progesterone concentration on days 7 and 6 before parturition was high (2.10 +/- 0.10 and 2.12 +/- 0.10 ng/ml, respectively). The level then decreased gradually and abrupt fall was observed 1-2 days before parturition and became basal on day of parturition (0.24 +/- 0.04 ng/ml). This basal level was maintained till the end of the blood sampling on day 90 postpartum. Plasma cortisol level showed an increasing trend beginning day 2 prior to parturition (2.36 +/- 0.65 ng/ml) and increased steeply thereafter to reach a peak level (26.65 +/- 5.28 ng/ml) on the day of parturition. The levels, then, declined gradually over the days and touched 2.36 +/- 0.25 ng/ml on day 3 postpartum and this level was maintained with fluctuation within narrow limits thereafter till day 7 post-calving.