Implant program effects on performance and carcass quality of steer calves finished for 212 days

We compared the effects of seven implant treatments combining use of Ralgro (RAL), Synovex-S (SYN), and Revalor-S (REV) on performance and beef quality traits of crossbred steer calves (n = 560) finished for 212 d. A randomized complete block design was used to compare treatments consisting of 1) non-implanted control (CON); 2) RAL on d 0, SYN on d 60, and REV on d 130 (RALSYNREV); 3) RAL on d 0, REV on d 60, and REV on d 130 (RALREVREV); 4) SYN on d 30 and REV on d 130 (SYNREV); 5) REV on d 30 and REV on d 130 (REVREV); 6) REV on d 0, REV on d 75, and REV on d 150, 12.5% crude protein diet (REV3X-12.5); and 7) REV on d 0, REV on d 75, and REV on d 150, 14.5% crude protein diet (REV3X-14.5). All implant groups had higher ADG and gained more efficiently (ADG: feed intake) than the CON group. No distinct performance advantages were noted for particular implant schemes. Implant treatments did not (P > .05) affect dressing percentage, carcass weight, or KPH fat percentage. Fat thickness did not differ (P > .05) for implanted vs CON steers; however, REVREV, SYNREV, and RALREVREV steers produced fatter carcasses than did REV3X-12.5 and RALSYNREV steers. The REV3X-12.5 and REV3X-14.5 treatments increased longissimus muscle area compared with CON; longissimus muscle areas for all other treatments did not differ (P > .05) from CON. No reduction in percentage of Choice and Prime carcasses occurred with use of SYNREV or REVREV; however, all treatments receiving three successive implants had lower (P < .05) percentages of Choice and Prime carcasses than the CON group. Increasing dietary crude protein seemed to lessen the detrimental effect of three successive REV implants on percentages of Choice and Prime carcasses. Loin steaks from REVREV, REV3X-12.5, and REV3X-14.5 steers had higher (P < .05) shear force values than steaks from CON steers.