21 CFR § 520.1120b - Haloxon boluses.

---
identifier: "/us/cfr/t21/s520.1120b"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "21 CFR § 520.1120b - Haloxon boluses."
title_number: 21
title_name: "Food and Drugs"
section_number: "520.1120b"
section_name: "Haloxon boluses."
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: "520"
part_name: "ORAL DOSAGE FORM NEW ANIMAL DRUGS"
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. 360b."
regulatory_source: "40 FR 13838, Mar. 27, 1975, unless otherwise noted."
cfr_part: "520"
---


# 520.1120b Haloxon boluses.

(a) *Specifications.* Each bolus contains 10.1 grams of haloxon.

(b) *Sponsor.* See No. 000061 in § 510.600(c) of this chapter.

(c) *Related tolerances.* See § 556.310 of this chapter.

(d) *Conditions of use in cattle*—(1) *Amount.* Administered one bolus per 500 pounds body weight (35 to 50 milligrams per kilogram of body weight). Retreat in 3 to 4 weeks.

(2) *Indications for use.* For control of gastrointestinal roundworms of the genera *Haemonchus, Ostertagia,* *Trichostrongylus,* and *Cooperia.*

(3) *Limitations.* Do not treat dairy animals of breeding age or older. Do not treat within 1 week of slaughter.

[40 FR 13838, Mar. 27, 1975, as amended at 44 FR 61591, Oct. 29, 1979; 46 FR 48642, Oct. 2, 1981; 61 FR 8873, Mar. 6, 1996; 62 FR 61625, Nov. 19, 1997; 78 FR 28822, May 20, 2014]