Code of Federal Regulations Title 21. Food and Drugs § 21.522.840 Estradiol

(1) Amount. Insert one 25.7–mg implant every 200 days;  insert one 43.9–mg implant every 400 days.

(2) Indications for use. 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. No additional effectiveness may be expected from reimplanting in less than 200 days for the 25.7–mg implant or 400 days for the 43.9–mg implant.

(3) Limitations. For subcutaneous ear implantation in steers and heifers only. Safety and effectiveness have not been established in veal calves. A withdrawal period has not been established for this product in preruminating calves. Do not use in calves to be processed for veal.