558.342—Melengestrol.

(a) Specifications. (1) Dry Type A medicated articles containing 100 or 200 milligrams (mg) melengestrol acetate per pound.

(2) Liquid Type A medicated article containing 500 mg melengestrol acetate per pound.

(b) Approvals. See sponsors in § 510.600(c) of this chapter for use as in paragraph (e) of this section.

(1) No. 000009 for use of products described in paragraph (a) of this section.

(2) No. 021641 for use of product described in paragraph (a)(2) of this section.

(d) Special considerations. (1) Type B or C medicated feeds may be manufactured from melengestrol acetate liquid Type A articles or Type B or C medicated feeds which have a pH of 4.0 to 8.0 and bear appropriate mixing directions as follows:

(i) For liquid feeds stored in recirculating tank systems: Recirculate immediately prior to use for no less than 10 minutes, moving not less than 1 percent of the tank contents per minute from the bottom of the tank to the top. Recirculate daily as described even when not used.

(ii) For liquid feeds stored in mechanical, air, or other agitation type tank systems: Agitate immediately prior to use for not less than 10 minutes, creating a turbulence at the bottom of the tank that is visible at the top. Agitate daily as described even when not used.

(2) A physically stable melengestrol acetate liquid Type B or C feed will not be subject to the requirements for mixing directions prescribed in paragraphs (c)(1) of this section provided it has a pH of 4.0 to 8.0 and contains a suspending agent(s) sufficient to maintain a viscosity of not less than 300 centipoises per second for 3 months.

(3) Combination Type B or C medicated feeds containing lasalocid must be labeled in accordance with § 558.311(d)(5) of this chapter.

(4) Liquid combination Type B or C medicated feeds containing melengestrol acetate and lasalocid must be manufactured in accordance with § 558.311(d) of this chapter.

(5) Combination Type B or C medicated feeds containing monensin must be labeled in accordance with § 558.355(d) of this chapter.

(6) Liquid combination Type B or C medicated feeds containing melengestrol acetate and monensin must be manufactured in accordance with § 558.355(f)(3)(i) of this chapter.

(7) Liquid combination Type B or C medicated feeds containing melengestrol acetate and tylosin must be manufactured in accordance with § 558.625(c) of this chapter.

(8) Liquid melengestrol acetate may not be mixed with oxytetracycline in a common liquid feed supplement.

(e) Conditions of use— (1) Cattle.

Melengestrol acetate in mg/head/day	Combination in mg/head/day	Indications for use	Limitations	Sponsor
(i) 0.25 to 0.5		Heifers fed in confinement for slaughter: For increased rate of weight gain, improved feed efficiency, and suppression of estrus (heat).	Administer 0.5 to 2.0 pounds (lb)/head/day of medicated feed containing 0.125 to 1.0 mg melengestrol acetate/lb to provide 0.25 to 0.5 mg melengestrol acetate/head/day.	000009, 021641
(ii) 0.5		Heifers intended for breeding: For suppression of estrus (heat).	Administer 0.5 to 2.0 lb/head/day of Type C feed containing 0.25 to 1.0 mg melengestrol acetate/lb to provide 0.5 mg melengestrol acetate/head/day. Do not exceed 24 days of feeding.	000009, 021641
(iii) 0.25 to 0.5	Lasalocid 100 to 360	Heifers fed in confinement for slaughter: As in paragraph (e)(1)(i) of this section.	Add at the rate of 0.5 to 2.0 lb/head/day a medicated feed (liquid or dry) containing 0.125 to 1.0 mg melengestrol acetate/lb to a feed containing 10 to 30 grams (g) of lasalocid per ton; or add at the rate of 0.5 to 2.0 lb/head/day a medicated feed (liquid or dry) containing 0.125 to 1.0 mg melengestrol acetate plus 50 to 720 mg lasalocid/lb to a ration of nonmedicated feed to provide 0.25 to 0.5 mg melengestrol acetate and 100 to 360 mg lasalocid/head/day.Lasalocid provided by No. 046573 in § 510.600(c) of this chapter.	000009, 021641
(iv) 0.25 to 0.5	Lasalocid 100 to 360 plus tylosin 90.	Heifers fed in confinement for slaughter: As in paragraph (e)(1)(i) of this section; and for reduced incidence of liver abscesses caused by Fusobacterium necrophorum and Actinomyces (Corynebacterium) pyogenes.	To administer 0.25 to 0.5 mg melengestrol acetate plus 100 to 360 mg lasalocid plus 90 mg tylosin/head/day:1. Add 0.5 to 2.0 lb/head/day of a liquid or dry medicated feed containing 0.125 to 1.0 mg melengestrol acetate/lb to a medicated feed containing 10 to 30 g lasalocid and 8 to 10 g tylosin per ton; or 2. Add 0.5 to 2.0 lb/head/day of a liquid or dry medicated feed containing 0.125 to 1.0 mg melengestrol acetate plus 50 to 720 mg lasalocid/lb to 4.5 to 18 lb of a dry medicated feed containing 10 to 40 g tylosin per ton; or 3. Add 0.5 to 2.0 lb/head/day of a dry pelleted medicated feed containing 0.125 to 1.0 mg melengestrol acetate (from a dry Type A article), 50 to 720 mg lasalocid, and 45 to 180 mg tylosin/lb to a ration of nonmedicated feed. Lasalocid provided by No. 046573 and tylosin as tylosin phosphate by No. 000986 in § 510.600(c) of this chapter. 021641
(v) 0.25 to 0.4	Monensin 50 to 360	Heifers fed in confinement for slaughter: As in paragraph (e)(1)(i) of this section.	Add at the rate of 0.5 to 2.0 lb/head/day a medicated feed (liquid or dry) containing 0.125 to 0.80 mg melengestrol acetate/lb to a feed containing 5 to 30 g monensin per ton; or add at the rate of 0.5 to 2.0 lb/head/day a medicated feed (liquid or dry) containing 0.125 to 0.80 mg melengestrol acetate plus 25 to 720 mg monensin/lb to a nonmedicated feed to provide 0.25 to 0.40 mg melengestrol acetate and 50 to 360 mg monensin/head/day. Monensin provided by No. 000986 in § 510.600(c) of this chapter.	021641
Code of Federal Regulations 453
(vi) 0.25 to 0.4	Monensin 50 to 360	Heifers fed in confinement for slaughter: As in item paragraph (e)(1)(i) of this section; and for the prevention and control of coccidiosis due to Eimeria bovis and E. zuernii.	Add at the rate of 0.5 to 2.0 lb/head/day a medicated feed (liquid or dry) containing 0.125 to 0.80 mg melengestrol acetate/lb to a feed containing 10 to 30 g monensin per ton; or add at the rate of 0.5 to 2.0 lb/head/day a medicated feed (liquid or dry) containing 0.125 to 0.80 mg melengestrol acetate plus 25 to 720 mg monensin/lb to a nonmedicated feed to provide 0.25 to 0.40 mg melengestrol acetate and 0.14 to 0.42 mg monensin/lb body weight, up to 360 mg monensin/head/day. Monensin provided by No. 000986 in § 510.600(c) of this chapter.	021641
(vii) 0.25 to 0.5	Monensin 50 to 360 plus tylosin 60 to 90	Heifers fed in confinement for slaughter: As in paragraph (e)(1)(i) of this section; for the prevention and control of coccidiosis due to E. bovis and E. zuernii; and for reduced incidence of liver abscesses caused by Fusobacterium necrophorum and Actinomyces (Corynebacterium) pyogenes.	To administer 0.25 to 0.50 mg melengestrol acetate to 50 to 360 mg monensin plus 60 to 90 mg tylosin/head/day:1. Add 0.5 to 2.0 lb/head/day of a liquid or dry medicated feed containing 0.125 to 1.0 mg melengestrol acetate/lb to a medicated feed containing 5 to 30 g monensin and 8 to 10 g tylosin per ton; or 2. Add 0.5 to 2.0 lb/head/day of a liquid or dry medicated feed containing 0.125 to 1.0 mg melengestrol acetate plus 25 to 720 mg monensin per pound to 4.5 to 18 lb of a dry medicated feed containing 10 to 40 g tylosin per ton; or 3. Add 0.5 to 2.0 lb/head/day of a liquid or dry medicated feed containing 0.125 to 1.0 mg melengestrol acetate, 25 to 600 mg monensin, and 45 to 180 mg tylosin/lb to a ration of nonmedicated feed. Monensin and tylosin as tylosin phosphate provided by No. 000986 in § 510.600(c) of this chapter.	000009, 021641
Code of Federal Regulations 454
(viii) 0.25 to 0.5	Oxytetracycline 75	Heifers fed in confinement for slaughter: As in paragraph (e)(1)(i) of this section; and for reduction of liver condemnation due to liver abscesses.	Add at the rate of 0.5 to 2.0 lb/head/day a medicated feed (liquid or dry) containing 0.125 to 1.0 mg melengestrol acetate/lb per pound to a feed containing 6 to 10 g oxytetracycline per ton; or add at the rate of 0.5 to 2.0 lb/head/day a dry medicated feed containing 0.125 to 1.0 mg melengestrol acetate plus 37.5 to 150 mg oxytetracycline/lb to provide 0.25 to 0.5 mg melengestrol acetate and 75 mg oxytetracycline/head/day.Oxytetracycline as provided by No. 066104 in § 510.600(c) of this chapter.	000009
(ix) 0.25 to 0.5	Tylosin 60 to 90	Heifers fed in confinement for slaughter: As in paragraph (e)(1)(i) of this section; and for reduced incidence of liver abscesses caused by F. necrophorum and Actinomyces (Corynebacterium) pyogenes.	To administer 0.25 to 0.5 mg melengestrol acetate with 60 to 90 mg tylosin/head/day:1. Add 0.5 to 2.0 lb/head/day of a liquid or dry medicated feed containing 0.125 to 1.0 mg melengestrol acetate/lb to a medicated feed containing 8 to 10 g tylosin per ton; or 2. Add 0.5 to 2.0 lb/head/day of a liquid or dry medicated feed containing 0.125 to 1.0 mg melengestrol acetate/lb to 4.5 to 18 pounds of a dry medicated feed containing 10 to 40 g tylosin per ton; or 3. Add 0.5 to 2.0 lb/head/day of a liquid or dry medicated feed containing 0.125 to 1.0 mg melengestrol acetate (from a dry Type A article) plus 45 to 180 mg tylosin/lb to a ration of nonmedicated feed. Tylosin as tylosin phosphate provided by No. 000986 in § 510.600(c) of this chapter.	000009, 021641
Code of Federal Regulations 455
(x) 0.25 to 0.5	Monensin 50 to 480.	Heifers fed in confinement for slaughter: As in paragraph (e)(1)(i) of this section; and for the prevention and control of coccidiosis due to Eimeria bovis and E. zuernii.	Add at the rate of 0.5 to 2.0 lb/head/day a medicated feed (liquid or dry) containing 0.125 to 1.0 mg melengestrol acetate/lb to a feed containing 10 to 40 g of monensin per ton to provide 0.25 to 0.5 mg melengestrol acetate/head/day and 0.14 to 0.42 mg monensin/lb body weight, depending on severity of coccidiosis challenge, up to 480 mg monensin/head/day.Monensin provided by No. 000986 in § 510.600(c) of this chapter.	000009
(xi) 0.25 to 0.5	Monensin 50 to 480, plus tylosin 60 to 90	Heifers fed in confinement for slaughter: As in paragraph (e)(1)(i) of this section; for the prevention and control of coccidiosis due to Eimeria bovis and E. zuernii; and for reduction of incidence of liver abscesses caused by Fusobacterium necrophorum and Arcanobacterium pyogenes.	Feed continuously as sole ration (liquid or dry) at a rate of 0.5 to 2.0 lb/head/day to provide 0.25 to 0.5 mg/head/day melengestrol acetate; 0.14 to 0.42 mg monensin/lb body weight/day, depending on the severity of the coccidiosis challenge, up to 480 mg/head/day; and 60 to 90 mg/head/day tylosin. The melengestrol acetate portion of this Type C medicated feed must be mixed into a complete feed containing 10 to 40 g/ton monensin and 8 to 10 g/ton tylosin in the amount of complete feed consumed by an animal per day.Monensin and tylosin phosphate provided by No. 000986 in § 510.600(c) of this chapter.	000009

(2) Melengestrol may also be used with:

(i) Ractopamine as in § 558.500 of this chapter.

(ii) Zilpaterol as in § 558.665 of this chapter.

Code of Federal Regulations

[42 FR 28535, June 3, 1977]

Code of Federal Regulations

Editorial Note: For Federal Register citations effecting § 558.342 , see the List of CFR Section Affected, which appears in the Finding Aids section of the printed volume and at www.fdsys.gov.