21 CFR § 520.2260aChapter I

§ 520.2260a Sulfamethazine oblets and boluses.

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Verbatim text below is from the Electronic Code of Federal Regulations (eCFR), a public-domain U.S. government work. Always verify the current version with the eCFR before relying on it for any legal matter.

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Specifications.(a) Each oblet or bolus contains:

(1) 2.5, 5, or 15 grams sulfamethazine.

(2) 5 grams sulfamethazine.

Sponsors.(b) See sponsors in § 510.600(c) of this chapter for use of products described in paragraph (a) of this section.

(1) No. 016592 for use of products described in paragraph (a)(1) of this section.

(2) No. 054771 for use of product described in paragraph (a)(2) of this section.

Related tolerances.(c) See § 556.670 of this chapter.

Conditions of use.(d) (1) Oblets and boluses described in paragraph (a)(1) of this section:

Amount.(i) Administer as a single dose 100 milligrams per pound (mg/lb) of body weight the first day and 50 mg/lb of body weight on each following day.

Indications for useBeef cattle and nonlactating dairy cattle.PasteurellaEscherichia coliFusobacterium necrophorumFusobacterium necrophorumStreptococcusStreptococcusEimeria bovisE. zurnii(ii) —(A) For the treatment of bacterial pneumonia and bovine respiratory disease complex (shipping fever complex) ( spp.), colibacillosis (bacterial scours) (), necrotic pododermatitis (foot rot) (), calf diphtheria (), acute mastitis ( spp.), acute metritis ( spp.), and coccidiosis ( and ).

Horses.PasteurellaStreptococcusEscherichia coli(B) For the treatment of bacterial pneumonia (secondary infections associated with spp.), strangles ( equi), and bacterial enteritis ().

Limitations.(iii) Do not administer for more than 5 consecutive days. Do not treat cattle within 10 days of slaughter. Do not use in female dairy cattle 20 months of age or older. Use of sulfamethazine in this class of cattle may cause milk residues. A withdrawal period has not been established for this product in preruminating calves. Do not use in calves to be processed for veal. Do not use in horses intended for human consumption. Federal law restricts this drug to use by or on the order of a licensed veterinarian.

(2) Boluses described in paragraph (a)(2) of this section:

Amount.(i) Administer 10 grams (2 boluses) of sulfamethazine per 100 pounds of body weight the first day, then 5 grams (1 bolus) of sulfamethazine per 100 pounds of body weight daily for up to 4 additional consecutive days.

Indications for useRuminating beef and dairy calves.Escherichia coli;Fusobacterium necrophorum;PasteurellaEimeria bovisE. zurnii.(ii) —(A) For treatment of the following diseases caused by organisms susceptible to sulfamethazine: bacterial scours (colibacillosis) caused by necrotic pododermatitis (foot rot) and calf diphtheria caused by bacterial pneumonia associated with spp.; and coccidiosis caused by and

(B) [Reserved]

Limitations.(iii) Do not administer for more than 5 consecutive days. Do not treat calves within 11 days of slaughter. Do not use in calves to be slaughtered under 1 month of age or in calves being fed an all milk diet. Do not use in female dairy cattle 20 months of age or older; such use may cause drug residues in milk. Federal law restricts this drug to use by or on the order of a licensed veterinarian.

[87 FR 58961, Sept. 29, 2022, as amended at 88 FR 14897, Mar. 10, 2023; 88 FR 16547, Mar. 20, 2023]

eCFR data current as of: June 10, 2026

This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.