Effects of Steroid Implants on the Tenderness of Beef

All cattle in the suckling through finishing phases of production respond to implants. In feedlot cattle, implants have been reported to improve ADG by 15 to 25% and feed efficiency by 10 to 15%. The resulting increase in saleable carcass and the associated benefits in feed efficiency make a regular, systematic implant program profitable for the producer. Recent research with anabolic steroid implants has demonstrated that growth occurs normally as a result of concomitant increases in bone, muscle, and fat, with proportions of these components staying relatively the same, but increased absolute amounts being deposited. In addition, feeding implanted(I)cattle longer so that they may reach physiological endpoint has been shown to compensate for decreased marbling, allowing I cattle to grade similarly to non-implanted(NI)cattle. Nonetheless, I cattle would be heavier at the same physiological endpoint, which could have both positive and negative effects on marketing schemes. The producer can adjust implant strategies to fit variable market conditions, including high vs low diet costs, live BW restrictions, carcass weight restrictions, and so on. By understanding how steroid implants work, coupled with knowledge of growth physiology, cattle genetics, and the market, a producer can use these tools to fit many different feeding and economic scenarios. There has been concern in the industry that androgenic implants, used alone or in combination with estrogenic implants, might decrease marbling or affect other palatability factors. Based on the data we reviewed, the currently available growth-promoting implants have limited, if any, effects on tenderness of beef as determined by Warner-Bratzler shear force(WBS)or taste panel evaluation of tenderness. Further research should be conducted to evaluate the effects of growth-promoting implants on calpain and calpastatin activities in muscle.