The effects of PGF2α on the conception rate and the plasma levels of estradiol-17β and progesterone of anestrus Cheju mares were investigated at the breeding and non-breeding seasons.
The results obtained from this studies are as follows;
1. The durations of the estrus and diestrus after PGF₂α treatment persisted shorter than control cycle (p<0.05), but ovulation time was fast.
2. The levels of estradiol-17β and progesteron before PGF₂α treatment showed 103.8pg/㎖, 8.0ng/㎖ in breeding season and 72.8pg/㎖, 4.7ng/㎖ in non-breeding season, respectively.
3. The levels of estradiol-17β rose to 115.4∼154.0pg/㎖, and 90.8∼27.0pg/㎖ from 2nd to 6th day after the treatment of PGF₂α, in breeding and non-breeding seasons, respectively, while progesterone level dropped to 1ng/㎖ with the sign of estrus and at 8th day rose in breeding season (p<0.05).
4. Of thirty anestrus mares investigated for PGF₂α administration, 87.5% showed estrus on an average of 3.8 days after treatment and the conception rate was 62.5% in breeding season, but the estrus and conception rates dropped 40% and 20% in non-breeding season, respectively.
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