Implantation or Injectable Dosage Form New Animal Drugs; Withdrawal of Approval of NADAs; Estradiol Benzoate

The Food and Drug Administration (FDA) is amending the animal drug regulations that reflect approval of two new animal drug applications (NADAs) for a suspension implant of estradiol benzoate microspheres used in steers and heifers fed in confinement for slaughter for increased rate of weight gain and improved feed efficiency, and in suckling beef calves for increased rate of weight gain. In a notice published elsewhere in this issue of the Federal Register, FDA has withdrawn approval of the NADAs.