21 C.F.R. § 558.140
Chlortetracycline and sulfamethazine.
Cite as 21 C.F.R. § 558.140 (2026)
(a)
Specifications.
Type A medicated articles containing:
(1) 35 grams (g) per pound (/lb) each, chlortetracycline and sulfamethazine.
(2) 40 g/lb each, chlortetracycline and sulfamethazine.
(b)
Sponsors.
See sponsors in § 510.600(c) of this chapter as follows:
(1) No. 054771 for use of product described in paragraph (a)(1) as in paragraph (e)(1) of this section.
(2) No. 069254 for use of product described in paragraph (a)(1) as in paragraph (e)(1)(i) of this section.
(3) Nos. 054771 and 069254 for use of product described in paragraph (a)(2) as in paragraph (e)(2) of this section.
(c)
Related tolerances.
See §§ 556.150 and 556.670 of this chapter.
(d)
Special considerations.
(1) 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.
(2) The expiration date of VFDs for chlortetracycline and sulfamethazine medicated feeds must not exceed 6 months from the date of issuance. VFDs for chlortetracycline and sulfamethazine shall not be refilled.
(e)
Conditions of use
—(1)
Cattle
—
Chlortetracycline
and sulfamethazine
amount each
Combination in
grams/ton
Indications for use
Limitations
Sponsors
(i) To provide 350 milligrams per head per day
Beef cattle: As an aid in the maintenance of weight gains in the presence of respiratory disease such as shipping fever.
Feed for 28 days. Withdraw 7 days prior to slaughter. A withdrawal period has not been established for this product in pre-ruminating calves. Do not use in calves to be processed for veal.
054771
069254
(ii) 35 to 105 g/ton, each
Lasalocid, 10 to 30
Beef steers and heifers fed in confinement for slaughter: As an aid in the maintenance of weight gains in the presence of respiratory disease such as shipping fever, and for improved feed efficiency.
Feed continuously for 28 days to provide 350 mg chlortetracycline, 350 mg sulfamethazine, and 100 to 300 mg lasalocid per head per day. Do not allow horses or other equines access to Type C feeds containing lasalocid as ingestion may be fatal. Safety of lasalocid for use in unapproved species has not been established. Withdraw 7 days prior to slaughter. A withdrawal period has not been established for this product in pre-ruminating calves. Do not use in calves to be processed for veal. Lasalocid as provided by No. 054771 in § 510.600(c) of this chapter.
054771
(iii) 35 to 42.2 g/ton, each
Lasalocid, 25 to 30
Beef steers and heifers fed in confinement for slaughter: As an aid in the maintenance of weight gains in the presence of respiratory disease such as shipping fever, and for improved feed efficiency and increased rate of weight gain.
Feed continuously for 28 days to provide 350 mg chlortetracycline, 350 mg sulfamethazine, and 250 to 300 mg lasalocid per head per day. Do not allow horses or other equines access to Type C feeds containing lasalocid as ingestion may be fatal. Safety of lasalocid for use in unapproved species has not been established. Withdraw 7 days prior to slaughter. A withdrawal period has not been established for this product in pre-ruminating calves. Do not use in calves to be processed for veal. Lasalocid as provided by No. 054771 in § 510.600(c) of this chapter.
054771
(iv) 35 to 700 g/ton, each
Lasalocid, 30 to 181.8
Beef cattle up to 800 lb: As an aid in the maintenance of weight gains in the presence of respiratory disease such as shipping fever, and for control of coccidiosis caused by
Eimeria bovis
and
E. zuernii
.
Hand feed continuously for 28 days to provide 350 mg chlortetracycline, 350 mg sulfamethazine, and 1 mg lasalocid per 2.2 lb body weight per day up to a maximum of 360 mg lasalocid per head per day. Do not allow horses or other equines access to Type C feeds containing lasalocid as ingestion may be fatal. Safety of lasalocid for use in unapproved species has not been established. Withdraw 7 days prior to slaughter. A withdrawal period has not been established for this product in pre-ruminating calves. Do not use in calves to be processed for veal. Lasalocid as provided by No. 054771 in § 510.600(c) of this chapter.
054771
(2)
Swine
—
Chlortetracycline and sulfamethazine amount
Indications for use
Limitations
Sponsors
(i) 100 g/ton of feed each, chlortetracycline and sulfamethazine
Swine: For reduction of the incidence of cervical abscesses; treatment of bacterial swine enteritis (salmonellosis or necrotic enteritis caused by
Salmonella choleraesuis
and vibrionic dysentery); prevention of these diseases during times of stress; and maintenance of weight gains in the presence of atrophic rhinitis
Feed as the sole ration. Withdraw 15 days prior to slaughter
054771
069254
(ii) [Reserved]
[79 FR 37622, July 2, 2014, as amended at 80 FR 13231, Mar. 13, 2015; 81 FR 63054, Sept. 14, 2016; 81 FR 95004, Dec. 27, 2016; 82 FR 21691, May 10, 2017; 84 FR 12495, Apr. 2, 2019; 86 FR 13189, Mar. 8, 2021; 86 FR 14822, Mar. 19, 2021]
- Cross-references to the CFR
- 510.600556.150558.6