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Objective The objective was to compare the effects of 4 implant management strategies involving long-duration implants on growth performance and dietary NE use of calf-fed Holstein steers. Materials and Methods A total of 192 calves were used in a 335-d experiment. Treatments were as follows: S1S1 = Synovex ONE (200 mg of trenbolone acetate and 28 mg of estradiol benzoate; Zoetis Animal Health, New York, NY) on arrival and Synovex ONE on d 168; S1SP = Synovex ONE on arrival and Synovex Plus (200 mg of trenbolone acetate and 28 mg of estradiol benzoate; Zoetis Animal Health) on d 224; SCE = Synovex C (100 mg of progesterone and 28 mg of estradiol benzoate; Zoetis Animal Health) on arrival and Encore (43.9 mg of estradiol; Elanco Animal Health, Greenfield, IN) on d 112; and SCS1 = Synovex C on arrival and Synovex ONE on d 112. Results and Discussion Steers implanted with Synovex ONE on arrival had greater (P Implications and Applications Implant strategies that incorporate long-acting implants to avoid terminal implantation when animals have greater days on feed did not improve calf-fed Holstein steer growth performance. Indeed, using a noncoated hormonal implant during the late finishing phase (implantation at 224 d on feed) increased overall peNEg, representing greater efficiency on cattle growth performance. |
