Implant Strategies for Yearling Steers

Various implant strategies were compared in heavy yearling steers fed for 98 days. Implant treatments included control (nonimplanted), 722 (72 mg zeranol), 36TBA (36 mg zeranol plus 140 mg trenbolone acetate [TBA]), 72TBA (72 mg zeranol plus TBA) and ETBA (20 mg estradiol-200 mg progesterone plus TBA). The 72-mg zeranol dosage represents two implants in one site. Combinations of implants were administered, one in each ear. Implanting increased (P\u3c.05) ADG and DM1 and decreased (P\u3c.05) feed/gain values. Among implanted steers, no differences (P\u3e.10) in ADG or DM1 were observed. Feed/gain was lower (P\u3c .05) for zeranol-TBA combinations than the 72-mg zeranol treatment. Carcasses were heavier and rib eye area was greater (P\u3c.05) in the 72TBA than 36TBA treatment. Kidney-pelvic-heart fat was lower (P\u3c.05) when the ETBA combination was used