1. (a) Specifications. Type A medicated articles containing either:

   1. (1) 25 percent sulfadimethoxine and 15 percent ormetoprim; or
   2. (2) 25 percent sulfadimethoxine and 5 percent ormetoprim.

2. (b) Sponsors. See sponsors in § 510.600(c) of this chapter as follows:

   1. (1) No. 054771 for use of the product described in paragraph (a)(1) as in paragraphs (e)(1), (e)(2)(i), and (e)(3)(i) through (iii) of this section.
   2. (2) No. 015331 for use of the product described in paragraph (a)(2) as in paragraphs (e)(3)(iv) and (v) of this section.
3. (c) Related tolerances. See §§ 556.490 and 556.640 of this chapter.

4. (d) Special considerations.

   1. (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. (2) The expiration date of VFDs for sulfadimethoxine and ormetoprim medicated feeds must not exceed 6 months from the date of issuance. VFDs for sulfadimethoxine and ormetoprim shall not be refilled.

5. (e) Conditions of use. It is used in animal feeds as follows:

   1. (1) Chickens—

      Sulfadimethoxineand ormetoprimgrams/ton	Indications for use	Limitations	Sponsors
      (i) Sulfadimethoxine, 113.5; ormetoprim, 68.1.	Broiler chickens: As an aid in the prevention of coccidiosis caused by all Eimeria species known to be pathogenic to chickens, namely, E. tenella, E. necatrix, E. acervulina, E. brunetti, E. mivati, and E. maxima, and bacterial infections due to Haemophilus gallinarum (infectious coryza), Escherichia coli (colibacillosis) and Pasteurella multocida (fowl cholera).	Feed as sole ration. Withdraw 5 days before slaughter.	066104
      (ii) Sulfadimethoxine, 113.5; ormetoprim, 68.1.	Replacement chickens: As an aid in the prevention of coccidiosis caused by all Eimeria species known to be pathogenic to chickens, namely, E. tenella, E. necatrix, E. acervulina, E. brunetti, E. mivati, and E. maxima, and bacterial infections due to Haemophilus gallinarum (infectious coryza), Escherichia coli (colibacillosis) and Pasteurella multocida (fowl cholera).	Feed as sole ration. Do not feed to chickens over 16 weeks (112 days) of age. Withdraw 5 days before slaughter.	066104

   2. (2) Turkeys—

      Sulfadimethoxineand ormetoprimgrams/ton	Indications for use	Limitations	Sponsors
      (i) Sulfadimethoxine, 56.75; ormetoprim, 34.05.	Turkeys: As an aid in the prevention of coccidiosis caused by all Eimeria species known to be pathogenic to turkeys, namely, E. adenoeides, E. gallopavonis, and E. meleagrimitis and bacterial infection due to Pasteurella multocida (fowl cholera).	Do not feed to turkeys producing eggs for food. Withdraw 5 days before slaughter.	054771
      (ii) [Reserved]

   3. (3) Minor species—

      Sulfadimethoxineand ormetoprim amount	Indications for use	Limitations	Sponsors
      (i) Sulfadimethoxine, 227; ormetoprim, 136.2 grams/ton of feed.	Ducks, including breeding ducks: As an aid in the control of bacterial infections due to Pasteurella multocida (fowl cholera).	Feed as sole ration for 7 days. Medication should be started at the first signs of infection. Do not feed to ducks producing eggs for food. Withdraw 5 days before slaughter.	054771
      (ii) Sulfadimethoxine, 454; ormetoprim, 272.4 grams/ton of feed.	Ducks: As an aid in the control of bacterial infections due to Escherichia coli, Riemerella anatipestifer, and severe challenge of Pasteurella multocida (fowl cholera).	Feed as a sole ration for 7 days. Medication should be started at the first signs of infection. Not for breeding ducks. Do not feed to ducks producing eggs for food. Withdraw 5 days before slaughter.
      (iii) Sulfadimethoxine, 113.5; ormetoprim, 68.1 grams/ton of feed.	Chukar partridges: For prevention of coccidiosis caused by Eimeria kofoidi and E. legionensis.	Feed continuously to young birds up to 8 weeks of age as sole ration.	054771
      (iv) 630 to 3780 g/ton sulfadimethoxine and 126 to 756 g/ton ormetoprim to provide 50 milligrams (mg) of active ingredients per kilogram of body per day	Salmonids: For the control of furunculosis in salmonids (trout and salmon) caused by Aeromonas salmonicida strains susceptible to sulfadimethoxine and ormetoprim combination	Administer for 5 consecutive days. Withdraw 42 days before release as stocker fish or slaughter	015331
      (v) 630 to 3780 g/ton sulfadimethoxine and 126 to 756 g/ton ormetoprim to provide 50 mg of active ingredients per kilogram of body per day	Catfish: For control of enteric septicemia of catfish caused by Edwardsiella ictaluri strains susceptible to sulfadimethoxine and ormetoprim combination	Administer for 5 consecutive days. Withdraw 3 days before slaughter or release as stocker fish	015331

[40 FR 13959, Mar. 27, 1975, as amended at 42 FR 13550, Mar. 11, 1977; 49 FR 33442, Aug. 23, 1984; 49 FR 46371, Nov. 26, 1984; 51 FR 7400, Mar. 3, 1986; 51 FR 18884, May 23, 1986; 52 FR 2686, Jan. 26, 1987; 54 FR 1686, Jan. 17, 1989; 63 FR 27846, May 21, 1998; 64 FR 26672, May 17, 1999; 64 FR 43910, Aug. 12, 1999; 66 FR 46707, Sept. 7, 2001; 70 FR 52292, Sept. 2, 2005; 79 FR 10983, Feb. 27, 2014; 79 FR 13546, Mar. 11, 2014; 81 FR 95013, Dec. 27, 2016; 83 FR 13637, Mar. 30, 2018; 84 FR 12502, Apr. 2, 2019; 86 FR 14827, Mar. 19, 2021; 87 FR 76424, Dec. 14, 2022; 91 FR 20347, Apr. 16, 2026]