Origin and characterisation of preovulatory follicles of hyperstimulated oestrous cycles in goats.
The origin and evolution of preovulatory follicles (POF) in 9 hyperstimulated (polyovulatory) Serrana goats were characterised. After oestrus synchronisation and detection, transrectal ovarian ultrasonography was performed daily during two complete oestrous cycles. Blood samples were taken every 4 h during 24 h after oestrus detection for preovulatory LH peak and twice a week for plasma progesterone determinations. The interovulatory interval of 14 oestrous cycles with double ovulations was 21.1 +/- 0.3 days. The onset of ovulatory follicular wave occurred 4 days (-3.9 +/- 0.3 days, n = 14) prior to the ovulation day (day 0) with a POF size of 6.9 +/- 0.2 mm (n = 28). In goats with ovulations in both ovaries (78.6%), the emergence of the first POF occurred earlier (-4.1 +/- 0.3 days) than the second POF (-3.3 +/- 0.2 days, n = 11, P < 0.05). No differences in the total number of follicles > or = 2 mm were found between the day of POF emergence (4.3 +/- 0.4) and the day before ovulation (3.5 +/- 0.3, P > 0.05). These results showed the existence of a delay between the emergence of first and second POF and suggest a weak dominance effect in goats with double ovulations.
Simões
J
J
CECAV, University of Trás-os-Montes e Alto Douro, Apartado 1013, 5001-811 Vila Real, Portugal. jsimoes@utad.pt
Mascarenhas
R
R
D000818:Animals; D030762:Estrous Cycle / Q000502:physiology*; D004973:Estrus Synchronization; D005260:Female; D006041:Goats / Q000502:physiology*; D007986:Luteinizing Hormone / Q000097:blood; D006080:Ovarian Follicle / Q000502:physiology*; D010060:Ovulation / Q000502:physiology*; D010061:Ovulation Detection / Q000379:methods / Q000662:veterinary; D011374:Progesterone / Q000097:blood
D011374:Progesterone; D007986:Luteinizing Hormone