21 CFR § 520.2345c - Tetracycline boluses.

---
identifier: "/us/cfr/t21/s520.2345c"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "21 CFR § 520.2345c - Tetracycline boluses."
title_number: 21
title_name: "Food and Drugs"
section_number: "520.2345c"
section_name: "Tetracycline 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"
---


# 520.2345c Tetracycline boluses.

(a) *Specifications.* Each bolus contains 500 milligrams of tetracycline (as the hydrochloride).

(b) *Sponsor.* See No. 054771 in § 510.600(c) of this chapter.

(c) *Related tolerances.* See § 556.720 of this chapter.

(d) *Conditions of use. Calves*—(1) *Amount.* 10 milligrams per pound of body weight per day in divided doses.

(i) *Indications for use.* Control and treatment of bacterial enteritis (scours) caused by *E. coli* and bacterial pneumonia caused by *Pasteurella* spp., *Hemophilus* spp., and *Klebsiella* spp.

(ii) *Limitations.* Administer orally for 3 to 5 days; do not slaughter animals for food within 14 days of treatment; use as sole source of tetracycline.

(2) *Amount.* 10 milligrams per pound of body weight per day in two divided doses.

(i) *Indications for use.* Treatment of bacterial pneumonia caused by organisms susceptible to tetracycline, bacterial enteritis caused by *E. coli,* and salmonella organisms susceptible to tetracycline.

(ii) *Limitations.* Administer orally for not more than 5 days; do not slaughter animals for food within 12 days of treatment; use as sole source of tetracycline.

[57 FR 37328, Aug. 18, 1992, as amended at 67 FR 78355, Dec. 24, 2002; 79 FR 28831, May 20, 2014; 81 FR 67151, Sept. 30, 2016]