Tenderness of Bos indicus influenced cattle as impacted by anabolic implants and gender



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Steers (n = 77) and heifers (n = 68) were assigned randomly to one of three treatment groups. Treatment groups were defined as: no implant, implanted twice with trenbolone acetate (Revalor S or H), or implanted twice with estrodial benzoate (Synovex S or H). Animals were fed to an estimated 10 mm backfat thickness and based on visual appraisal, were assigned a harvest date. Carcass characteristics, color space values, sarcomere length, fat and moisture determination, Warner-Bratzler shear force, and protein degradation were all measured. Implanted animals, as a whole, exhibited heavier hot carcass weights and larger ribeye areas than non-implanted animals. Animals implanted with Revalor displayed significantly lower marbling scores and lower yield grades than those from control or Synovex groups. The distribution of quality grades within treatment groups shifted, with implant groups displaying higher percentages of Select carcasses. Gender impacted percentage of extractable fat and marbling scores, with heifers displaying higher values than steers for both measurements. Both implant groups displayed higher (P < 0.05) Warner-Bratzler shear values following a 0- and 14-d aging periods. However, following the 21-d aging period, differences in tenderness were no longer present between non-implanted and implanted animals. Synovex treated animals displayed longer (P < 0.01) sarcomere lengths than control or Revalor. Differences (P < 0.001) in protein degradation were found between treatment groups. Across gender groups, the non-implanted cattle displayed the greatest amount of degradation (62%), followed by Synovex (48%,) and lastly Revalor (33%), all of which were different (P < .05) from each other. These results indicate that use of anabolic implants positively impacted lean muscle growth, yet was a detriment to quality. Also, tenderness was negatively impacted by the use of these compounds. However, this study found by aging product for at least 21 days, tenderness differences between implanted and non-implanted animals were significantly mitigated.