Effect of complexed trace minerals on cumulus-oocyte complex recovery and in vitro embryo production in beef cattle1,2.

The objective of this experiment was to evaluate the impact of complexed trace mineral supplementation on ovum pick-up (OPU) and in vitro embryo production in lactating beef cows. Thirty days prior to fixed-time artificial insemination (FTAI; day -30), 68 postpartum cows were stratified by BW, BCS, and parity before being randomly assigned to 10 pens of either a treatment (TRT; n = 5) or a control (CNT; n = 5) group. Each group received a weekly mineral supplement allotment of 1.

Pre- and post-weaning injections of bovine somatotropin to optimize puberty achievement of beef heifers.

The present study evaluated the growth and puberty attainment of heifers administered recombinant bovine somatotropin (bST) or saline injections during preweaning and/or postweaning. On day 0, 177 suckling Nellore heifers were stratified by initial age and body weight (BW) (80 ± 10 d; 97 ± 16 kg), and randomly assigned, in a 2 × 2 factorial design ( = 44 to 45 heifers/treatment), to receive s.c.