---
kind: "section"
citation: "21 C.F.R. § 522.460"
title: "21"
number: "522.460"
heading: "Cloprostenol."
url: "https://uscodex.org/cfr/21/522.460"
---

# §522.460. Cloprostenol.

- (a) **Specifications.** Each milliliter of solution contains cloprostenol sodium equivalent to:
  - (1) 125 micrograms (µg) of cloprostenol; or
  - (2) 250 µg of cloprostenol.
- (b) **Sponsors.** See sponsors in [§ 510.600(c)](/cfr/21/510.600.md?p=c) of this chapter.
  - (1) **No.** 000061 for use of product described in [paragraph (a)(1)](#a-1) of this section as in paragraphs [(c)(1)(i)](#c-1-i) and (c)(2) of this section.
  - (2) **No.** 000061 for use of product described in [paragraph (a)(2)](#a-2) as in paragraphs [(c)(1)(ii) through (viii)](#c-1-ii..c-1-viii) and (c)(2) of this section.
  - (3) **No.** 068504 for use of product described in [paragraph (a)(2)](#a-2) as in paragraphs [(c)(1)(ii) through (vii)](#c-1-ii..c-1-vii), [(c)(1)(ix)](#c-1-ix), and (c)(2) of this section.
- (c) **Conditions of use in cattle—**
  - (1) **Amount and indications for use.**
    - (i) Administer 375 µg by intramuscular injection to induce abortion in pregnant feedlot heifers from 1 week after mating until 4 1/2 months of gestation.
    - (ii) Administer 500 µg by intramuscular injection for unobserved or non-detected estrus in beef cows, lactating dairy cows, and replacement beef and dairy heifers.
    - (iii) Administer 500 µg by intramuscular injection for treatment of pyometra or chronic endometritis in beef cows, lactating dairy cows, and replacement beef and dairy heifers.
    - (iv) Administer 500 µg by intramuscular injection for treatment of mummified fetus in beef cows, lactating dairy cows, and replacement beef and dairy heifers.
    - (v) Administer 500 µg by intramuscular injection for treatment of luteal cysts in beef cows, lactating dairy cows, and replacement beef and dairy heifers.
    - (vi) Administer 500 µg by intramuscular injection for abortion of beef cows, lactating dairy cows, and replacement beef and dairy heifers from 1 week after mating until 5 months of gestation. Not for use in heifers placed in feedlots.
    - (vii) Administer 500 µg by intramuscular injection as a single injection regimen or double injection regimen with a second injection 11 days after the first injection, for estrus synchronization in beef cows, lactating dairy cows, and replacement beef and dairy heifers.
    - (viii) For use with gonadorelin acetate to synchronize estrous cycles to allow for fixed time artificial insemination (FTAI) in lactating dairy cows: administer to each cow 86 µg gonadorelin by intramuscular injection, followed 6 to 8 days later by 500 µg cloprostenol by intramuscular injection, followed 30 to 72 hours later by 86 µg gonadorelin by intramuscular injection. Gonadorelin acetate as provided in [§ 522.1077(a)(1)](/cfr/21/522.1077.md?p=a-1) of this chapter.
    - (ix) **For use with gonadorelin to synchronize estrous cycles to allow for FTAI in lactating dairy cows—** administer to each cow by intramuscular injection, followed 6 to 8 days later by 500 µg cloprostenol by intramuscular injection, followed 30 to 72 hours later by gonadorelin by intramuscular injection. Gonadorelin as provided in [§ 522.1077(a)(1) through (3)](/cfr/21/522.1077.md?p=a-1..a-3) of this chapter.
  - (2) **Limitations.** Federal law restricts this drug to use by or on the order of a licensed veterinarian.

## Notes

### Amendments

[79 FR 16185, Mar. 25, 2014, as amended at 85 FR 4208, Jan. 24, 2020; 88 FR 84700, Dec. 6, 2023]

### Authority

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

### Source

Source: 40 FR 13858, Mar. 27, 1975, unless otherwise noted.

### Amendments

[79 FR 16185, Mar. 25, 2014, as amended at 85 FR 4208, Jan. 24, 2020; 88 FR 84700, Dec. 6, 2023]