21 CFR § 522.840 - Estradiol.
(a) Specifications. Each silicone rubber implant contains 25.7 or 43.9 milligrams (mg) estradiol and is coated with not less than 0.5 mg oxytetracycline powder.
(b) Sponsor. See No. 058198 in § 510.600(c) of this chapter.
(c) Related tolerances. See § 556.240 of this chapter.
(d) Conditions of use. For implantation in steers and heifers as follows:
(1) Amounts and indications for use—(i) 25.7-mg extended-release implant. Insert one implant for increased rate of weight gain for up to 200 days in beef steer calves 2 months of age and older; for increased rate of weight gain for up to 200 days in growing beef steers and heifers on pasture (stocker, feeder, and slaughter); and for increased rate of weight gain and improved feed efficiency for up to 200 days in growing beef steers and heifers fed in confinement for slaughter.
(ii) 43.9-mg extended-release implant. Insert one implant for increased rate of weight gain for up to 400 days in beef steer calves 2 months of age and older; for increased rate of weight gain for up to 400 days in growing beef steers and heifers on pasture (stocker, feeder, and slaughter); and for increased rate of weight gain and improved feed efficiency for up to 400 days in growing beef steers and heifers fed in confinement for slaughter.
(2) Limitations. For subcutaneous ear implantation only. Not approved for repeated implantation (reimplantation) with this or any other cattle ear implant within each separate production phase (beef steer calves 2 months of age and older, growing beef steers on pasture (stocker, feeder, and slaughter), growing beef steers and heifers fed in confinement for slaughter). Safety and effectiveness following reimplantation have not been evaluated. Do not use in beef calves less than 2 months of age, dairy calves, and veal calves. A withdrawal period has not been established for this product in pre-ruminating calves. Do not use in dairy cows or in animals intended for subsequent breeding. Use in these cattle may cause drug residues in milk and/or in calves born to these cows.