[Code of Federal Regulations] [Title 21, Volume 6] [Revised as of April 1, 2001] From the U.S. Government Printing Office via GPO Access [CITE: 21CFR558.342] [Page 418-421] TITLE 21--FOOD AND DRUGS CHAPTER I--FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES--(Continued) PART 558--NEW ANIMAL DRUGS FOR USE IN ANIMAL FEEDS--Table of Contents Subpart B--Specific New Animal Drugs for Use in Animal Feeds Sec. 558.342 Melengestrol acetate. (a) Approvals. Dry Type A medicated articles containing 100 or 200 milligrams per pound or liquid Type A article containing 500 milligrams per pound to 000009 in Sec. 510.600(c) of this chapter. (b) Related tolerances. See Sec. 556.380 of this chapter. [[Page 419]] (c) 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 Type B or C 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 Type B or C 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 positionally 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. (d) Conditions of use. It is used for heifers as follows: (1) Amount. Melengestrol acetate, 0.25 to 0.50 milligram per head per day. (i) Indications for use. For increased rate of weight gain, improved feed efficiency, and suppression of estrus (heat). (ii) Limitations: Heifers being fed for slaughter; administer 0.5 to 2.0 pounds per head per day of medicated feed containing 0.125 to 1.0 milligram of melengestrol acetate per pound to provide 0.25 to 0.50 milligram of melengestrol acetate per head per day. Melengestrol acetate as provided by No. 000009 in Sec. 510.600(c) of this chapter. (2) Amount: Melengestrol acetate, 0.25 to 0.40 milligram per head per day, plus monensin (as monensin sodium), 50 to 360 milligrams per head per day. (i) Indications for use. For increased rate of weight gain, improved feed efficiency, and supression of estrus (heat). (ii) Limitations: Heifers being fed in confinement for slaughter. Add at the rate of 0.5 to 2.0 pounds per head per day a medicated feed (liquid or dry) containing 0.125 to 0.80 milligram of melengestrol acetate per pound to a feed containing 5 to 30 grams of monensin per ton; or, add at the rate of 0.5 to 2.0 pounds per head per day a medicated feed (liquid or dry) containing 0.125 to 0.80 milligram of melengestrol acetate plus 25 to 720 milligrams of monensin per pound to a nonmedicated feed to provide 0.25 to 0.40 milligram of melengestrol acetate and 50 to 360 milligrams of monensin per head per day. The liquid medicated feeds must be manufactured in accordance with Sec. 558.355(f)(3)(i). Melengestrol acetate and monensin as provided by Nos. 000009 and 000986, respectively, in Sec. 510.600(c) of this chapter. (3) Amount. Melengestrol acetate, 0.25 to 0.50 milligram per head per day in combination with lasalocid (as lasalocid sodium), 100 to 360 milligrams per head per day. (i) Indications for use. For increased rate of weight gain, improved feed efficiency, and suppression of estrus (heat). (ii) Limitations. Heifers being fed in confinement for slaughter. The liquid medicated feeds are required to be manufactured in accordance with Sec. 558.311(d). Add at the rate of 0.5 to 2.0 pounds per head per day a medicated feed (liquid or dry) containing 0.125 to 1.0 milligram of melengestrol acetate per pound to a feed containing 10 to 30 grams of lasalocid per ton; or, add at the rate of 0.5 to 2.0 pounds per head per day a medicated feed (liquid or dry) containing 0.125 to 1.0 milligram of melengestrol acetate plus 50 to 720 milligrams of lasalocid per pound to a ration of nonmedicated feed to provide 0.25 to 0.5 milligram of melengestrol acetate and 100 to 360 milligrams of lasalocid per head per day. Melengestrol acetate and lasalocid as provided by Nos. 000009 and 063238, respectively, in Sec. 510.600(c) of this chapter. (4) Amount. Melengestrol acetate, 0.25 to 0.50 milligram per head per day, plus tylosin (as tylosin phosphate), 90 milligrams per head per day. (i) Indications for use. For increased rate of weight gain, improved feed efficiency, suppression of estrus (heat), [[Page 420]] and reduced incidence of liver abscesses. (ii) Limitations. Heifers being fed in confinement for slaughter. Melengestrol acetate and tylosin as provided by Nos. 000009 and 000986, respectively, in Sec. 510.600(c) of this chapter. To administer 0.25 to 0.50 milligram of melengestrol acetate with 90 milligrams of tylosin per head per day: (A) Add 0.5 to 2.0 pounds per head per day of a liquid or dry medicated feed containing 0.125 to 1.0 milligram of melengestrol acetate per pound to a medicated feed containing 8 to 10 grams of tylosin per ton; or (B) Add 0.5 to 2.0 pounds per head per day of a liquid or dry medicated feed containing 0.125 to 1.0 milligram of melengestrol acetate per pound to 4.5 to 18 pounds of a dry medicated feed containing 10 to 40 grams of tylosin per ton; or (C) Add 0.5 to 2.0 pounds per head per day of a dry medicated feed containing 0.125 to 1.0 milligram of melengestrol acetate (from a dry Type A article) plus 45 to 180 milligrams of tylosin per pound to a ration of nonmedicated feed. (5) Amount. Melengestrol acetate, 0.25 to 0.50 milligram per head per day, plus monensin (as monensin sodium) at 50 to 360 milligrams per head per day, plus tylosin (as tylosin phosphate), 90 milligrams per head per day. (i) Indications for use. For increased rate of weight gain, improved feed efficiency, suppression of estrus (heat), and reduced incidence of liver abscesses. (ii) Limitations. Heifers being fed in confinement for slaughter. The liquid medicated feeds are required to be manufactured in accordance with Sec. 558.355(f)(3)(i). Melengestrol acetate as provided by No. 000009 and monensin and tylosin as provided by No. 000986 in Sec. 510.600(c) of this chapter. To administer 0.25 to 0.50 milligram of melengestrol acetate to 50 to 360 milligrams of monensin plus 90 milligrams of tylosin per head per day: (A) Add 0.5 to 2.0 pounds per head per day of a liquid or dry medicated feed containing 0.125 to 1.0 milligram of melengestrol acetate per pound to a medicated feed containing 5 to 30 grams of monensin and 8 to 10 grams of tylosin per ton; or (B) Add 0.5 to 2.0 pounds per head per day of a liquid or dry medicated feed containing 0.125 to 1.0 milligram of melengestrol acetate plus 25 to 720 milligrams of monensin per pound to 4.5 to 18 pounds of a dry medicated feed containing 10 to 40 grams of tylosin per ton; or (C) Add 0.5 to 2.0 pounds per head per day of a dry medicated feed containing 0.125 to 1.0 milligram melengestrol acetate (from a dry Type A article), 25 to 600 milligrams of monensin, and 45 to 180 milligrams of tylosin per pound to a ration of nonmedicated feed. (6) Amount. Melengestrol acetate, 0.25 to 0.50 milligram per head per day, plus lasalocid (as lasalocid sodium), 100 to 360 milligrams per head per day, and tylosin (as tylosin phosphate), 90 milligrams per head per day. (i) Indications for use. For increased rate of weight gain, improved feed efficiency, suppression of estrus (heat), and reduced incidence of liver abscesses. (ii) Limitations. Heifers being fed in confinement for slaughter. The liquid medicated feeds are required to be manufactured in accordance with Sec. 558.311(d). Lasalocid, melengestrol acetate, and tylosin as provided by Nos. 000009, 000986, and 063238 respectively, in Sec. 510.600(c) of this chapter. To administer 0.25 to 0.50 milligram of melengestrol acetate plus 100 to 360 milligrams of lasalocid plus 90 milligrams of tylosin per head per day: (A) Add 0.5 to 2.0 pounds per head per day of a liquid or dry medicated feed containing 0.125 to 1.0 milligram of melengestrol acetate per pound to a medicated feed containing 10 to 30 grams of lasalocid and 8 to 10 grams of tylosin per ton; or (B) Add 0.5 to 2.0 pounds per head per day of a liquid or dry medicated feed containing 0.125 to 1.0 milligram of melengestrol acetate plus 50 to 720 milligrams of lasalocid per pound to 4.5 to 18 pounds of a dry medicated feed containing 10 to 40 grams of tylosin per ton; or (C) Add 0.5 to 2.0 pounds per head per day of a dry pelleted medicated feed containing 0.125 to 1.0 milligram of melengestrol acetate (from a dry Type [[Page 421]] A article), 50 to 720 milligrams of lasalocid, and 45 to 180 milligrams of tylosin per pound to a ration of nonmedicated feed. (7) Amount. 0.5 milligram per head per day. (i) Indications for use. For suppression of estrus (heat). (ii) Limitation. Heifers intended for breeding. Do not exceed 24 days of feeding. Administer 0.5 to 2.0 pounds per head per day of Type C feed containing 0.25 to 1.0 milligram of melengestrol acetate per pound to provide 0.5 milligram of melengestrol acetate per head per day. Melengestrol acetate as provided by No. 000009 in Sec. 510.600(c) of this chapter. (8) Amount. Melengestrol acetate, 0.25 to 0.5 milligram per head per day, plus oxytetracycline, 75 milligrams per head per day. (i) Indications for use. For increased rate of weight gain, improved feed efficiency, suppression of estrus (heat), and reduction of liver condemnation due to liver abscesses. (ii) Limitations. Heifers fed in confinement for slaughter. Add at the rate of 0.5 to 2.0 pounds per head per day a medicated feed (liquid or dry) containing 0.125 to 1.0 milligram of melengestrol acetate per pound to a feed containing 6 to 10 grams of oxytetracycline per ton; or add at the rate of 0.5 to 2.0 pounds per head per day a dry medicated feed containing 0.125 to 1.0 milligram of melengestrol acetate plus 37.5 to 150 milligrams of oxytetracycline per pound to provide 0.25 to 0.5 milligram of melengestrol acetate and 75 milligrams of oxytetracycline per head per day. Liquid melengestrol acetate may not be mixed with oxytetracycline in a common liquid feed supplement. Melengestrol acetate as provided by 000009, oxytetracycline by 000069, in Sec. 510.600(c) of this chapter. [42 FR 28535, June 3, 1977, as amended at 46 FR 18967, Mar. 27, 1981; 49 FR 39842, Oct. 11, 1984; 50 FR 1843, Jan. 14, 1985; 50 FR 16228, Apr. 25, 1985; 51 FR 7398, Mar. 3, 1986; 51 FR 36222, Oct. 9, 1986; 52 FR 2685, Jan. 26, 1987; 52 FR 33804, Sept. 8, 1987; 53 FR 27959, July 26, 1988; 55 FR 31828, Aug. 6, 1990; 57 FR 5053, Feb. 12, 1992; 59 FR 41241, Aug. 11, 1994; 60 FR 11028, Mar. 1, 1995; 62 FR 8373, Feb. 25, 1997; 62 FR 14304, Mar. 26, 1997; 63 FR 27845, May 21, 1998; 63 FR 41191, Aug. 3, 1998; 63 FR 66018, Dec. 1, 1998]