PSXIII-19 - The influence of weaning age and biocholine supplementation to post-weaning growth and reproductive development in Brangus heifers

This experiment was conducted to determine the effect of earlier weaning in addition to biocholine supplementation on age at puberty of Brangus heifers. Brangus calves were randomized and divided into three weaning ages groups, at 30 (Hyper-early weaning; HW), 75 (Early weaning; EW) and 180 days (Conventional weaning; CW). Then, calves were supplemented using the additive Biocholine (BIO) or not (CON). Animals were subjected to puberty induction and transrectal ultrasonography was performed to assess the ovarian activity and the presence of corpus luteum to determine heifer puberty. We also evaluated the body weight (BW; Kg), hip height (HH; cm), thoracic perimeter (TP; cm) and BW:HH ratio during the experimental period. BIO group showed higher ADG ( >226g/day) when the animals were exposed to ryegrass pasture compared to CON (P < 0.05). We observed an interaction between weaning x biocholine and CW-BIO heifers showed greater HH more compared to CW-CON (P < 0.05). Overall, animals that have reached puberty at day 8 after puberty induction showed 331.0±23.14kg BW, 122.0±2.58cm HH and 165.4±3.45cm TP and 2.7±0.14 BW:HH. At the time of ovulation detection, the heifers from the HW group had 32.1kg BW, 3.93cm HH and 0.18cm BW:HH greater compared to CW (P < 0.05). The BIO supplementation together with ryegrass pasture, led to an increase in ADG weight throughout the evaluated period. We concluded that HW heifers showed an adequate body development throughout the experimental period until puberty appearance at the same age as others weaned groups.