Considerable attention has been focused on the cryopreservation of semen and estrus induction in dog, as consequence of poor productivity caused by long anestrus period, in order to enhance the productivity of youngs and to preserve the breeds. The objectives of this study were to develop a treatment protocol for estrus induction. Fifty infertilie dogs (age 2∼3 years) were selected for the study and divided into three different estrus induction treatment groups. Group 1: dogs (n=15) were given clomifane (0.1 mg/kg) orally for five days at 12 hr intervals. Group 2: dogs (n=15) were given bromocriptine (50 /kg) orally for five days at 12 hr intervals, followed by single injection intravenously of 500 IU GnRH (Group 3, n=20) when pro-estrus occurred. After being treated, the dogs were evaluated for the rates of estrus induction and time interval lapses from treatment to beginning of the pro-estrus. The estrus induction rates were significantly (P<0.05) higher in both group 2 (9/15, 73.3%) and group 3 (16/20, 80.0%) than that of group 1 (9/15, 60.0%), but did not differ in the groups 2 and 3. No differences were observed in the time interval lapses from treatment to beginning of the pro-estrus in group 2 (7.7 1.2 days) and group 3 (6.9 2.0 days), but significantly (P<0.05) shorter than that of group 1 (9.5 2.1 days). In conclusion, the estrus induction rate of dogs treated with a combination of GnRH and bromocriptine was more effective than use of clomifene or bromocriptine only.

Intracytoplasmic Sperm Injection (ICSI) has been widely used fur both human infertility and basic research. However, the high incidence of chromosomal abnormality is severe problem in cattle. Various oocyte activation stimuli, therefore, were compared by assessment of developmental capacity and chromosome analysis. Motile sperm selected by Percoll-density gradient were treated with 5 mM dithiothreitol (DTT) and injected into an oocyte matured fur 24 h. Eggs were then allocated into 5 treatment groups. Group 1 (control), sperm injection was performed without any further activation stimuli to the oocytes. Group 2 (handled control), sham injection was performed without sperm. In Group 3, oocytes exposed to 5 (M ionomycin for 5 min at 39(C. Group 4. ionomycine + 1.9 mM demethylaminopurine (DMAP, 3 h) and Group 5, ionomycine + 3 h culture in Ml99 + DMAP. Cleavage and the later development rate in Groups 1, 2 and 3 were significantly (P<0.05) lower than those in Groups 4 and 5. The incidence of chromosomal abnormality in the embryos treated directly with DMAP after ionomycine was relatively higher than in the embryo of Group 3 h, delayed DMAP treatment. From this results DMAP caused to be arrested the release of the 2nd polar body, resulting in changes of chromosomal pattern. Therefore, the time interval between ionomycin and DMAP is a crucial role in bovine ICSI.