Maternal serum progesterone concentration during pregnancy and lamb birth weight at parturition in Javanese Thin-Tail ewes with different litter sizes

摘要

Blood samples were taken from 38 Javanese Thin-Tailed ewes (body weight 20-22 kg, age 2-3 years) pregnant with 1, 2 or 3 fetuses at weekly intervals throughout pregnancy. There was no difference in serum progesterone concentration among ewes carrying 1, 2 and 3 fetuses during weeks 0-7 of pregnancy (5.3±0.3, 6.2±0.7 and 6.6±0.5 ng/ml respectively). However during weeks 8-20, ewes carrying 2 and 3 fetuses had higher progesterone concentrations than those carrying a single fetus (25.3±1.5 and 26.8±2.5 vs. 16.9±1.4 ng/ml respectively; P<0.01). Total lamb birth weight in ewes carrying 1, 2 and 3 fetuses was 1.9±0.1, 3.2±0.2 and 4.2±0.4 kg, respectively. Within the groups, ewes with higher mean serum progesterone concentration during the whole pregnancy gave birth to lambs with higher birth weights (r2 = 0.76, 0.42 and 0.46 for ewes carrying 1, 2 and 3 fetuses, respectively).