1. (a) Specifications. Each pellet contains 12, 18, or 20 milligrams (mg) zeranol.
2. (b) Sponsor. See 000061 in § 510.600(c) of this chapter.
3. (c) Related tolerances. See § 556.760 of this chapter.
4. (d) Conditions of use—(1) Beef cattle—(i) Amount. 36 mg zeranol (one implant consisting of 3 pellets, each pellet containing 12 mg zeranol) per implant dose.
5. (ii) Indications for use.(A) For increased rate of weight gain and improved feed efficiency in growing beef steers and heifers fed in confinement for slaughter.
6. (B) For increased rate of weight gain in beef calves 2 months of age or older, in growing beef steers and heifers on pasture (stocker, feeder, and slaughter), and in growing beef steers and heifers in a dry lot.
7. (iii) Limitations. Implant pellets subcutaneously only. Not approved for repeated implantation (reimplantation) with this or any other cattle ear implant within a single production phase as safety and effectiveness have not been evaluated. Do not use in beef calves less than 2 months of age, dairy calves, and veal calves because effectiveness and safety have not been evaluated. A withdrawal period has not been established for this product in preruminating calves. Do not use in replacement beef heifers after weaning or in bulls, dairy cows, or replacement dairy heifers.
8. (2) Feedlot lambs—(i) Amount. 12 mg zeranol (one implant consisting of 1 pellet containing 12 mg zeranol) per implant dose.
9. (ii) Indications for use. For increased rate of weight gain and improved feed conversion.
10. (iii) Limitations. Implant subcutaneously in ear only. Do not use in breeding animals. Do not implant animals within 40 days of slaughter. 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.
11. (3) Steers fed in confinement for slaughter—(i) Amount. 72 mg zeranol (one implant consisting of 6 pellets, each pellet containing 12 mg zeranol) per implant dose.
12. (ii) Indications for use. For increased rate of weight gain and improved feed efficiency.
13. (iii) Limitations. Implant subcutaneously in ear 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.
14. (4) Pasture cattle (slaughter, stocker, feeder steers, and heifers)—(i) Amount. 138 mg zeranol (one implant consisting of 7 pellets, each of 6 pellets containing 20 mg zeranol and a seventh pellet containing 18 mg zeranol) per implant dose.
15. (ii) Indications for use. For increased rate of weight gain.
16. (iii) Limitations. Implant subcutaneously in ear 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.

[59 FR 19639, Apr. 25, 1994; 60 FR 26360, May 17, 1995, as amended at 62 FR 61625, Nov. 19, 1997; 64 FR 46840, Aug. 27, 1999; 67 FR 6867, Feb. 14, 2002; 70 FR 6764, Feb. 9, 2005; 88 FR 55566, Aug. 16, 2023; 91 FR 5301, Feb. 6, 2026]