Evaluation of Two Grass-Based Implants in a Short Season Summer Grazing Management Practice

Implants are a cost-effective tool to aid in growth enhancement in beef cattle. Implants are heavily used in feedlot systems, with moderate to high usage in grazing systems. Each implant has different payout characteristics, generally as a result of varying coating technologies. A new grass-based implant has come on the market with a long-duration payout window. The objective of this study was to evaluate two implants in stocker steers on a double-stocked 90 d grazing season. The two implants were Revalor®-G (REV; Merck Animal Health, Summit, NJ) and Synovex® One Grass (SYN; Pfizer Animal Health, New York NY) which should have a quick payout and extended payout, respectively. Steers (n = 241) were weighed with an overnight shrink prior to turnout, midpoint, and end of grazing period. At initial weigh date steers were implanted with respective implants and assigned to one of seven pastures in a completely randomized block design with pasture as block. Within each pasture cattle on both implants grazed together. Performance was evaluated for total gains, gains in the first ½ of the season, and in the second ½ of the grazing season. Average daily gain was not different (P = 0.35) based on implant type (1.16 ± 0.02 kg/d for REV and 1.13 ± 0.02 kg/d for SYN). Total BW gain was not different (P = 0.72; 100.95 ± 2.27 kg for REV vs 99.63 ± 2.27 lb for SYN). Additionally, BW gain and ADG were similar (P > 0.43) between implants in both the early grazing (first 44 d) and late grazing season (d 45 – 90). Overall, cattle performance was similar regardless of coating technology in implants in a short duration grazing period with stocker steers. Cost is a factor in selecting implants in this management system. The SYN implant costs $4.95/animal while REV costs $1.38/implant. Due to similar performance and the lower cost of the implant, Revelor®-G provides the more economical implant strategy for a double stock 90 d grazing system found in the Flint Hills of Kansas.