After the induction of estrus by the PGFF2$alpha$-GTH combination on the 118 repeat breeder cow during of 6-13 days of the estrus cycle, the effects of GTH, antibiotics, antibiotics-GTH combination were compared. The results of this study, the following conclusion were obtained: 1. The rate of estrus was reduced the administration of GTH before the administration of PGF2$alpha$. 2. The rate of ovulation delayed was 24.6% in the group with the administration GTH, but 34.1% without the administration GTH. Duration of ovulation was shortened by GTH. 3. The impregnation induction by the administration of PGF2$alpha$, PGF2$alpha$-antibiotics, PGF2$alpha$-GTH-antibiotics were 41.7%, 69.5%, 55.6% and 80.8% respectively injection in the uterus was more effective than the administration. Before or after the A.I., the above combination was most effective. 4. In antibiotics sensitivity test in vitro of the intravagina bacteria, 5.0%, 12.7% and 60.0% of bacteria were sensitive to Penicilline, Streptomycin and Gentamicin respectively.