---
kind: "section"
citation: "21 C.F.R. § 520.90c"
title: "21"
number: "520.90c"
heading: "Ampicillin boluses."
url: "https://uscodex.org/cfr/21/520.90c"
---

# §520.90c. Ampicillin boluses.

- (a) **Specifications.** Each bolus contains ampicillin trihydrate equivalent to 400 milligrams of ampicillin.
- (b) **Sponsor.** See No. 054771 in [§ 510.600(c)](/cfr/21/510.600.md?p=c) of this chapter.
- (c) **Related tolerances.** See [§ 556.40](/cfr/21/556.40.md) of this chapter.
- (d) **Conditions of use in nonruminating calves—**
  - (1) **Amount.** 5 milligrams per pound of body weight twice daily not to exceed 4 days.
  - (2) **Indications for use.** Oral treatment of bacterial enteritis (colibacillosis) caused by E. coli.
  - (3) **Limitations.** Treated calves must not be slaughtered for food during treatment and for 7 days after the last treatment. Federal law restricts this drug to use by or on the order of a licensed veterinarian.

## Notes

### Amendments

[57 FR 37322, Aug. 18, 1992, as amended at 58 FR 61016, Nov. 19, 1993; 60 FR 55659, Nov. 2, 1995; 79 FR 28818, May 20, 2014. Redesignated and amended at 85 FR 18118, Apr. 1, 2020]

### Authority

Authority: 21 U.S.C. 360b.

### Source

Source: 40 FR 13838, Mar. 27, 1975, unless otherwise noted.

### Amendments

[57 FR 37322, Aug. 18, 1992, as amended at 58 FR 61016, Nov. 19, 1993; 60 FR 55659, Nov. 2, 1995; 79 FR 28818, May 20, 2014. Redesignated and amended at 85 FR 18118, Apr. 1, 2020]