Site Feedback

Title 21

Displaying title 21, up to date as of 10/08/2026. Title 21 was last amended 10/06/2026.
New Finding Aids are now available on eCFR.gov. The Parallel Table of Authorities, Subject Index, and Agency-prepared Indexes are now online! Learn more
eCFR Content

The Code of Federal Regulations (CFR) is the official legal print publication containing the codification of the general and permanent rules published in the Federal Register by the departments and agencies of the Federal Government. The Electronic Code of Federal Regulations (eCFR) is a continuously updated online version of the CFR. It is not an official legal edition of the CFR.

Learn more about the eCFR, its status, and the editorial process.

§ 558.58 Amprolium and ethopabate.

(a) Specifications. Type A medicated articles containing:

(1) 25 percent amprolium and 8 percent ethopabate or 5 percent amprolium and 1.6 percent ethopabate;

(2) 25 percent amprolium and 0.8 percent ethopabate or 5 percent amprolium and 0.16 percent ethopabate.

(b) Sponsor. See No. 016592 in § 510.600(c) of this chapter.

(c) Related tolerances. See §§ 556.50 and 556.260 of this chapter.

(d) Special considerations. Do not use in Type B or Type C medicated feeds containing bentonite.

(e) Conditions of use. It is used in chicken feed as follows:

Amprolium and ethopabate in grams per ton Combination in grams per ton Indications for use Limitations Sponsor
(1) Amprolium 113.5 and ethopabate 3.6 Broiler chickens: As an aid in the prevention of coccidiosis Feed continuously as sole ration; as sole source of amprolium. Not for laying chickens 016592
(2) Amprolium 113.5 and ethopabate 36.3 Broiler chickens and replacement chickens: where immunity to coccidiosis is not desired: As an aid in the prevention of coccidiosis where severe exposure to coccidiosis from Eimeria acervulina, E. maxima, and E. brunetti is likely to occur Feed continuously as sole ration; as sole source of amprolium. Not for chickens over 16 weeks of age 016592
(3) Amprolium 113.5 and ethopabate 36.3 Bacitracin 4 to 50 1. Broiler chickens and replacement chickens: where immunity to coccidiosis is not desired; to aid in prevention of coccidiosis where severe exposure to coccidiosis from Eimeria acervulina, E. maxima, and E. brunetti is likely to occur; for increased rate of weight gain in broiler chickens raised in floor pens Feed as the sole ration from the time chickens are placed on litter until past the time when coccidiosis is ordinarily a hazard. Not for chickens over 16 weeks of age; do not feed to laying chickens; as sole source of amprolium; not for use as a treatment for outbreaks of coccidiosis. Bacitracin as bacitracin methylenedisalicylate as provided by No. 054771 in § 510.600(c) of this chapter 016592
(4) Amprolium 113.5 and ethopabate 36.3 Bacitracin (as feed grade bacitracin zinc) 4 to 50 2. Broiler chickens: As an aid in prevention of coccidiosis where severe exposure to coccidiosis from Eimeria acervulina, E. maxima, and E. brunetti is likely to occur; for improved feed efficiency Feed as the sole ration from the time birds are placed on litter until past the time when coccidiosis is ordinarily a hazard, up to 16 weeks of age. If losses exceed 0.5% in a 2-day period, obtain an accurate diagnosis and follow the instructions of your veterinarian or poultry pathologist. Do not feed to chickens producing eggs for human consumption. Not for chickens over 16 weeks of age. Do not feed as a treatment for outbreaks of coccidiosis. Do not change the litter while giving this feed unless absolutely necessary. Use as the sole source of amprolium. Do not use in feeds containing bentonite. Bacitracin zinc as provided by No. 054771 in § 510.600(c) of this chapter. 066104
(5) Amprolium 113.5 and ethopabate 36.6 Bambermycins 1 to 3 Broiler chickens: As an aid in the prevention of coccidiosis where severe exposure to coccidiosis from Eimeria acervulina, E. maxima, and E. brunetti is likely to occur; for increased rate of weight gain, improved feed efficiency Feed continuously as the sole ration; as sole source of amprolium
Bambermycins as provided by No. 016592 in § 510.600(c) of this chapter
016592
(6) Amprolium 227 and ethopabate 3.6 For broiler chickens and replacement chickens where immunity to coccidiosis is not desired; prevention of coccidiosis Not for laying chickens 016592

(f) Amprolium and ethopabate may also be used in combination with:

(1)-(2) [Reserved]

(3) Chlortetracycline as in § 558.128.

[41 FR 10990, Mar. 15, 1976]