책임운영기관 농촌진흥청 국립축산과학원 (로고)

Background: Hanwoo cattle farmers aim to improve calf production and reproductive efficiency. Recovery of the reproductive tract postpartum is a critical factor influencing the postpartum period and conception of breeding cows. This study aimed to precisely analyze the recovery process of the reproductive tract in primiparous Hanwoo postpartum and to establish recovery criteria.Methods: Ten primiparous Hanwoo cows were used in this study. After parturition, estrus was examined daily using visual observations and estrus detection patches.Ovarian recovery, cervical diameter, and uterine horn diameter were examined using ultrasonography four times per week.Results: The analysis revealed that the first estrus occurred at 19.1 ± 6.5 days postpartum, the first ovulation at 27.1 ± 4.5 days, and the first normal estrus cycle at 39.2 ± 6.4 days. The ovulation rate during the first estrus was 40%. A normal estrus cycle occurred in 11.1% of patients at the first ovulation. The cervix diameter recovered to 42.0 ± 3.5 mm and the uterine horn diameter to 34.4 ± 7.1 mm by 24 days postpartum, with the difference in uterine horn diameter recovering to 2.6 ± 1.2 mm by 31 days postpartum.Conclusions: This study can aid in determining the optimal breeding time for postpartum primiparous Hanwoo cow and provide foundational data for Hanwoo breeding studies.