Estrus was induced and the therapeutic effect was examined with 25mg of PGF2$alpha$ intramuscular injection and 3mg of PGF2$alpha$ intraovarian injection to Holstein and Simmental cows which were raised in the large size stockfarms and the dairy farms, and were diagnosed to anestrus. The results obtained were summarized as follows: 1. The estrus inducing effect observed in the cows treated by PGF2$alpha$ was 83.3% with 25/30 heads in the intramuscular injection group, and 86.7% with 26/30 heads in the intraovarian injection group. 2. Average duration from PGF2$alpha$ administration to the onest of estrus was 2.7 day in the intramuscular injection group, and 2.6 days in the intraovarian injection group. 3. In status of estrus in the cows treated by PGF2$alpha$, vigorous estrus was 12.0%, normal estrus 60.0% and silent estrus was 28.0% in the intramuscular injection group, and vigorous estrus was 15.4%, normal estrus 61.5%, and silent estrus 23.1% in the intraovarian injection group. 4. Conception rate in the cows induced to estrus was 64.0% in the intramuscular injection group and 65.4% in the intraovarian injection group.