Plasma progesterone in alpaca (Lama pacos) during pregnancy, parturition and early postpartum

Plasma progesterone concentration during pregnancy and the early postpartum period was measured by radioimmunoassay in five alpacas (Lama pacos), of the Huacaya breed, whose pregnancy length had a mean of 344.8 +/- 4.4 days. Concentration of progesterone increased (P < 0.001) from low premating values (0.11 +/- 0.06 nmol/l) to greater values at 30 days of pregnancy (8.05 +/- 1.13 nmol/l) and remained high up to 2 months of pregnancy. A slight transitory decline was observed between 3 to 7 months. Concentration of plasma progesterone dropped markedly during the 72 h before parturition especially, at the day of parturition.