The aim of the present study was to best the efficiency of estrous induction in. the premature, metestrous and anestrous bitches.
The estrus was induced with prostaglandin :F₂α, estradiol-17β, pregnant mare serum gonadotropin(PMSG) and human chorionic gonadotropin(HCG) in the treatment A, and with PMSG and HCG in the treatment B. Day 0 was the first day of estrone injection in the treatment A and the day of PMSG injection in the treatment B. Twenty three of the twenty six bitches were laparotomized under general anesthesia between 11 and 18 days after onset of behavioral estrus, whereas three bitches were not laparotomized and remained until parturition. Ovarian responses were evaluated with the tota1 number of corpora lutea or ovulation sites. The uterine horns were flushed with phosphate-buffered saline added heat treated canine serum(10%), the flushing media was collected into watch glass and the ova were examined under stereomicroscope.
The results obtained were as follows:
1. Standing estrus was observed on the day 17.7±1.5 after injection of estrone in the treament A, but ovarian responses were not detectable.
2. Standing estrus was observed on the day 12.2±0.2 after injection of PMSG in the treatment B and 14 of 17 bitches showed ovarian responses. Ova were recovered in 9 of the 14 bitches.
3. Ovarian responses were observed in one of the three premature bitches, two of the three metestrous bitches and all of the 11 anestrous bitches. The average number of the ova collected from 9 bitchs were 12.2±1.4
4. Three bitches in the treatment B exhibited behavioural estrus and all of them were mated with fertile male dog, resulting the pregnancy in only tine bitch. The pregnant bitch gave the birth of two pups.
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