§558.635. Virginiamycin.
21 C.F.R. § 558.635
Specifications. Type A medicated articles containing 10, 20, 50, or 227 grams virginiamycin per pound.
Sponsors. See No. 066104 in § 510.600(c) of this chapter.
Related tolerances. See § 556.750 of this chapter.
Special considerations.
Federal law restricts medicated feed containing this veterinary feed directive (VFD) drug to use by or on the order of a licensed veterinarian. See § 558.6 for additional requirements.
The expiration date of VFDs for virginiamycin medicated feeds must not exceed 6 months from the date of issuance. VFDs for virginiamycin shall not be refilled.
Not for use in breeding swine over 120 pounds.
Dilute Type A article with at least 10 pounds of a feed ingredient prior to final mixing in 1 ton of Type C feed.
Conditions of use—
Chickens—
Swine—
Cattle—
Notes, amendments, and revision history
Amendments
[81 FR 95022, Dec. 27, 2016, as amended at 82 FR 11512, Feb. 24, 2017; 82 FR 21692, May 10, 2017; 85 FR 18125, Apr. 1, 2020; 87 FR 10972, Feb. 28, 2022; 88 FR 14908, Mar. 10, 2023; 90 FR 40972, Aug. 22, 2025]
Authority
Authority: 21 U.S.C. 354, 360b, 360ccc, 360ccc-1, 371.
Source
Source: 40 FR 13959, Mar. 27, 1975, unless otherwise noted.
Amendments
[81 FR 95022, Dec. 27, 2016, as amended at 82 FR 11512, Feb. 24, 2017; 82 FR 21692, May 10, 2017; 85 FR 18125, Apr. 1, 2020; 87 FR 10972, Feb. 28, 2022; 88 FR 14908, Mar. 10, 2023; 90 FR 40972, Aug. 22, 2025]