Short Communication: Evaluation of 2 implants for growing steers grazing tall-grass prairie when using intensive early stocking

ABSTRACT Commercial implants can have different coating technologies, carriers, and hormone amounts that result in different payout characteristics and effects on cattle growth. Therefore, the objective of this study was to evaluate 2 implants in stocker steers on a 90-d grazing season. Implants were Revalor-G (REV), which contains 40 mg of trenbolone acetate and 8 mg of estradiol, is uncoated, and has a cholesterol carrier, or Synovex One Grass (SYN), which contains 150 mg of trenbolone acetate and 21 mg of estradiol benzoate and has a porous polymer coating. Steers (n = 242) were weighed with an overnight shrink on d 0, 44, and 91. Steers were implanted on d 0 and assigned to 1 of 7 pastures in a completely randomized complete block design with pasture as block. Total gains and gains in each half of the grazing season were evaluated. Average daily gain was not different based on implant type ( P = 0.35; 1.16 kg/d for REV and 1.13 kg/d for SYN; SEM = 0.02) nor was total BW gain ( P = 0.65; 101 kg for REV vs. 100 kg for SYN; SEM = 2.3). Additionally, BW gain and ADG were not different between implants in both sections of the grazing period ( P ≥ 0.45). Overall, cattle performance was not different regardless of hormone amount and coating technology in implants in a short-duration grazing period with stocker steers, and these data do not support a price premium for SYN over REV in this grazing system.