Section 522.1940 - Progesterone and estradiol benzoate(a)Specifications -(1)Each implant consists of progesterone and estradiol benzoate.(i) 100 mg progesterone and 10 mg estradiol benzoate (one implant consisting of four pellets, each containing 25 mg progesterone and 2.5 mg estradiol benzoate).(ii) 200 mg progesterone and 20 mg estradiol benzoate (one implant consisting of eight pellets, each containing 25 mg progesterone and 2.5 mg estradiol benzoate).(2)Each implant consists of progesterone and estradiol benzoate and tylosin tartrate.(i) 100 mg progesterone, 10 mg estradiol benzoate, and 29 mg tylosin tartrate (one implant consisting of four pellets, each containing 25 mg progesterone and 2.5 mg estradiol benzoate, and one pellet containing 29 mg tylosin tartrate).(ii) 200 mg progesterone, 20 mg estradiol benzoate, and 29 mg tylosin tartrate (one implant consisting of eight pellets, each containing 25 mg progesterone and 2.5 mg estradiol benzoate, and one pellet containing 29 mg tylosin tartrate).(b)Sponsors. See sponsors in § 510.600(c) of this chapter for use as in paragraph (c) of this section:(1) No. 054771 for use as in paragraphs (e)(1)(i)(A), (e)(1)(ii), (e)(2)(i)(A), (B), (C), and (e)(2)(ii) of this section.(2) No. 058198 for use as in paragraphs (e)(1)(i)(A), (e)(1)(i)(B), (e)(1)(ii), and (e)(3) of this section.(c)Related tolerances. See §§ 556.240 and 556.540 of this chapter.(d)Special considerations. Labeling of implants described in paragraphs (a)(2)(i) and (a)(2)(ii) for use in paragraphs (e)(1)(i)(B), (e)(1)(ii), (e)(3)(i), and (e)(3)(ii) of this section shall bear the following: "Federal law restricts this drug to use by or on the order of a licensed veterinarian."(e)Conditions of use - (1)Beef calves 45 days of age and older and weighing up to 400 lbs - (i)Amounts and indications for use.(A) An implant containing 100 mg progesterone and 10 mg estradiol benzoate as described in paragraph (a)(1)(i) of this section for increased rate of weight gain.(B) An implant containing 100 mg progesterone, 10 mg estradiol benzoate, and 29 mg tylosin tartrate as described in paragraph (a)(2)(i) of this section for increased rate of weight gain.(ii)Limitations. Implant pellets subcutaneously in ear only. Other than when used as described in (e)(2)(i)(B) of this section, the implant as described in paragraph (a)(1)(i) of this section is not approved for repeated implantation (reimplantation). The implant as described in paragraph (a)(2)(i) of this section is not approved for repeated implantation (reimplantation) with this or any other cattle ear implant. Do not use in beef calves less than 45 days of age, dairy calves, and veal calves because effectiveness and safety have not been evaluated. 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 calves born to these cows.(2)Growing beef steers fed in confinement for slaughter -(i)Amounts and indications for use.(A) An implant containing 200 mg progesterone and 20 mg estradiol benzoate as described in paragraph (a)(1)(ii) of this section for increased rate of weight gain and improved feed efficiency.(B) An implant containing 200 mg progesterone and 20 mg estradiol benzoate as described in paragraph (a)(1)(ii) of this section for increased rate of weight gain in a reimplantation program where an implant as described in paragraph (a)(1)(i) of this section is the first implant and an implant as described in paragraph (a)(1)(ii) of this section is administered approximately 70 days later.(C) An implant containing 200 mg progesterone and 20 mg estradiol benzoate as described in paragraph (a)(1)(ii) of this section for increased rate of weight gain in a reimplantation program where an implant as described in paragraph (a)(1)(ii) of this section is the first implant and an implant as described in paragraph (a)(1)(ii) of this section is administered approximately 70 days later.(ii)Limitations. Implant pellets subcutaneously in ear only. Other than when used as described in paragraphs (e)(2)(i)(B) or (C) of this section, the implant described in paragraph (a)(1)(ii) of this section is not approved for repeated implantation (reimplantation) with any other cattle ear implant in growing beef steers and heifers fed in confinement for slaughter 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. 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 calves born to these cows.(3)Growing beef steers weighing 400 lbs or more -(i)Amounts and indications for use. An implant containing 200 mg progesterone, 20 mg estradiol benzoate, and 29 mg tylosin tartrate as described in paragraph (a)(2)(ii) of this section for increased rate of weight gain and improved feed efficiency.(ii)Limitations. The implant as described in paragraph (a)(2)(ii) of this section is not approved for repeated implantation (reimplantation) with this or any other cattle ear implant. 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. 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 calves born to these cows.89 FR 42358, May 15, 2024 81 FR 48702, 7/26/2016; 87 FR 17946, 3/29/2022; 88 FR 55566, 8/16/2023; 89 FR 42358, 5/15/2024