21 CFR § 558.58 - Amprolium and ethopabate.
---
identifier: "/us/cfr/t21/s558.58"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "21 CFR § 558.58 - Amprolium and ethopabate."
title_number: 21
title_name: "Food and Drugs"
section_number: "558.58"
section_name: "Amprolium and ethopabate."
chapter_name: "FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES"
subchapter_number: "E"
subchapter_name: "ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS"
part_number: "558"
part_name: "NEW ANIMAL DRUGS FOR USE IN ANIMAL FEEDS"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "21 U.S.C. 354, 360b, 360ccc, 360ccc-1, 371."
regulatory_source: "40 FR 13959, Mar. 27, 1975, unless otherwise noted."
cfr_part: "558"
---
# 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 and 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 and 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 4 to 50 | 2. Broiler chickens: As an aid in prevention of coccidiosis where severe exposure to coccidiosis from and is likely to occur; for improved feed efficiency | Feed as the sole ration from the time chickens are placed on litter until market weight. 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 coccidiosis. Bacitracin zinc as provided by No. 054771 in § 510.600(c) of this chapter | 054771 |
| (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 and is likely to occur; for increased rate of weight gain, improved feed efficiency | Feed continuously as the sole ration; as sole source of amproliumBambermycins 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]
For citations affecting § 558.58, see the List of CFR Sections Affected, which appears in the Finding Aids section of the printed volume and at