| Popis: |
Relationships between circulating progesterone profiles and those of the luteotrophic hormones luteinising hormone (LH) and prolactin were examined at different times of day in two groups of 19 and 18 Greyface ewes in a high level of body condition (H; condition score ≥3.5) or moderate level of condition (M; condition score 2.5/2.75). These levels of body condition were maintained from 4 weeks before mating at a synchronised oestrus until slaughter at approximately 5 weeks post mating. On day 10 post mating, blood samples were collected at 20-min intervals during two periods of 6 h during the day (10:00–16:00) and night (22:00–04:00). All samples were assayed for progesterone, LH and prolactin. There were no significant effects of level of body condition on mean ovulation rates, pregnancy rates and ova wastage rates or on progesterone, LH and prolactin profiles. Mean progesterone concentrations were lower during the day than at night (3.2 vs. 3.6 ng ml−1; P |
