Received: 21-05-2020 / Accepted: 01-07-2020
The study was designed to determine the effects of estrus induction method combined fixed-time artificial insemination (FTAI) in dairy cows. This study was conducted on 17 sixteen-month-old prepubertal heifers and 34 repeat breeder cows in Vinh Phuc province between July and November 2019. Hormones therapy and progesterone device were used to induce estrus and performed artificial insemination during 14-18 hours after finish the treatment. Pregnancy diagnosis was performed from 60 days after FTAI date. The results have indicated that the insemination rate and the conception rate were 100% (51/51 cows) and 37.25% (19/51 cows), respectively. Regarding the non-pregnant group, the estrus resumption proportion was 96.87% (31/32 cows). In conclusion, the significant effects of estrus synchronization and fixed-time artificial insemination (FTAI) were proved to increase the insemination rate and to promote cow to return to the normal physiological estrus cycle, although the first service conception rate was not high after treatment.