Evaluation of Revalor® implants for stocker-finishing steers

Abstract

Revalor® implants (containing trenbolone acetate plus estradiol) were evaluated in a grazing-finishing system using steers with a known previous implant history. Grazing gains were not improved by either Ralgro® or Revalor implants, suggesting that previously implanted steers may not respond to implants during a later growing phase. During the finishing phase, steers implanted with Revalor gained 5.4 to 8.0% faster (P<.05) than steers implanted with Synovex-S®. Gain efficiency in the finishing period was improved 4.8% (P<.10) for steers receiving no pasture implant and a Revalor implant during the finishing phase (0R), compared with steers receiving Ralgro/Synovex (RS) or Revalor/Revalor (RR) implants in the pasture/feedlot phases. Steers implanted with RR had larger (P<.05) ribeye areas than RS steers, with 0R steers intermediate. However, RR steers had a 20 percentage unit reduction (P<.05) in carcasses reaching the choice grade compared to RS steers. Revalor can improve steer feedlot performance, but multiple implantation may reduce quality grade.