In this study, pregnancy per timed-AI was 44.2% for pre- and peripubertal (RTS ¼ 1, 2, and 3) and 61.9% for pubertal (RTS ¼ 4 and 5) heifers. Therefore, we concluded that the RTS system used in the present study was useful in estimating puberty
status and provided similar results regarding its effects on fertility compared with previous reports.