---
kind: "section"
citation: "21 C.F.R. § 558.305"
title: "21"
number: "558.305"
heading: "Laidlomycin propionate potassium."
url: "https://uscodex.org/cfr/21/558.305"
---

# §558.305. Laidlomycin propionate potassium.

- (a) **Specifications.** Type A medicated articles containing 50 grams laidlomycin propionate potassium per pound.
- (b) **Sponsor.** See No. 054771 in [§ 510.600(c)](/cfr/21/510.600.md?p=c) of this chapter.
- (c) **Tolerances.** See [§ 556.346](/cfr/21/556.346.md) of this chapter.
- (d) **Special considerations.**
  - (1) Laidlomycin propionate potassium Type B liquid medicated feeds may be manufactured from dry laidlomycin propionate potassium Type A medicated articles. The Type B liquid medicated feeds must have a pH of 6.0 to 8.0, dry matter of 62 to 75 percent, and bear appropriate mixing directions as follows:
    - (i) **For liquid feeds stored in recirculating tank systems—** Recirculate immediately prior to use for no less than 10 minutes, moving not less than 1 percent of the tank contents per minute from the bottom of the tank to the top. Recirculate daily as described even when not used.
    - (ii) **For liquid feeds stored in mechanical, air, or other agitation type tank systems—** Agitate immediately prior to use for not less than 10 minutes, creating a turbulence at the bottom of the tank that is visible at the top. Agitate daily as described even when not used.
  - (2) **The expiration date of the Type B liquid medicated feed is 21 days after date of manufacture.** The expiration date for the dry Type C medicated feed made from the Type B liquid medicated feed is 7 days after date of manufacture.
  - (3) Labeling for all Type B medicated feeds (liquid and dry) and Type C medicated feeds containing laidlomycin propionate potassium shall bear the following statements:
    - (i) **Do not allow horses or other equines access to feeds containing laidlomycin propionate potassium.**
    - (ii) **The safety of laidlomycin propionate potassium in unapproved species has not been established.**
    - (iii) **Not for use in animals intended for breeding.**
- (e) **Conditions of use.** It is used in growing beef steers and heifers fed in confinement for slaughter as follows:
- (f) Laidlomycin propionate potassium may also be used in combination with chlortetracycline as in [§ 558.128](/cfr/21/558.128.md).

## Notes

### Amendments

[59 FR 18297, Apr. 18, 1994, as amended at 60 FR 53509, Oct. 16, 1995; 62 FR 9929, Mar. 5, 1997; 63 FR 27845, May 21, 1998; 66 FR 46706, Sept. 7, 2001; 68 FR 13839, Mar. 21, 2003; 68 FR 42590, July 18, 2003; 69 FR 30198, May 27, 2004; 79 FR 13545, Mar. 11, 2014; 81 FR 95005, Dec. 27, 2016; 86 FR 14823, Mar. 19, 2021; 91 FR 20343, Apr. 16, 2026; 91 FR 33072, June 3, 2026]

### Authority

Authority: 21 U.S.C. 354, 360b, 360ccc, 360ccc-1, 371.

### Source

Source: 40 FR 13959, Mar. 27, 1975, unless otherwise noted.

### Amendments

[59 FR 18297, Apr. 18, 1994, as amended at 60 FR 53509, Oct. 16, 1995; 62 FR 9929, Mar. 5, 1997; 63 FR 27845, May 21, 1998; 66 FR 46706, Sept. 7, 2001; 68 FR 13839, Mar. 21, 2003; 68 FR 42590, July 18, 2003; 69 FR 30198, May 27, 2004; 79 FR 13545, Mar. 11, 2014; 81 FR 95005, Dec. 27, 2016; 86 FR 14823, Mar. 19, 2021; 91 FR 20343, Apr. 16, 2026; 91 FR 33072, June 3, 2026]