Each silicone rubber implant contains 43.9 mg estradiol and is coated with not less than 0.5 mg of oxytetracycline powder as a local antibacterial. For SQ ear implantation in steers and heifers only for increased rate of weight gain in suckling and pastured growing steers; for improved feed efficiency and increased rate of weight gain in confined steers and heifers. Do not use in veal calves.