ANABOLIC IMPLANT EFFECTS ON STEER PERFORMANCE, CARCASS TRAITS, SUBPRIMAL YIELDS, AND LONGISSIMUS MUSCLE PROPERTIES

Crossbred steers (n = 140; 353 kg) were implanted as follows: (C) cont rol, no implant; (S) Synovex-S(R) (20 mg estradiol benzoate + 200 mg p rogesterone); (R) Revalor(R) (20 mg estradiol + 140 mg trenbolone acet ate [TEA]; international dosage); (ST) S + finaplix-S(R) (140 mg TEA); (STT) S + finaplix-S with finaplix-S reimplanted on d 58. Steers were harvested after 119 to 126 d on feed. Left sides of 40 carcasses were fabricated into boneless subprimals for two s.c. fat levels: 2.5 and .64 cm. Steers administered an estrogen (estradiol benzoate or estradi ol) plus TEA gained more rapidly (P < .05) than C or S steers. Feed ef ficiency was improved (P < .05) with an estrogen plus TEA. No differen ces (P > .05) were noted among treatments for carcass s.c. fat thickne ss, percentage internal fat, or lean color.