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United States • Title 21 CFR • Part 526

Part 526PART 526—INTRAMAMMARY DOSAGE FORM NEW ANIMAL DRUGS

Part 526 outlines the requirements for intramammary dosage forms of new animal drugs, specifying their use in cattle for mastitis treatment. It details drug specifications, sponsors, related tolerances, and conditions of use, including dosage, indications, and limitations such as milk discard and preslaughter withdrawal periods. The regulations also address specific drugs like Amoxicillin, Ceftiofur, Cephapirin, Cloxacillin, Erythromycin, Hetacillin, Novobiocin, and Penicillin G procaine.

What this part covers

  • Specifies requirements for intramammary dosage forms of new animal drugs.
  • Details drug specifications, including active ingredient, dosage, and formulation.
  • Outlines conditions of use for lactating and dry cows, including treatment regimens.
  • Provides indications for use, specifying the types of mastitis and causative organisms.
  • Establishes limitations, such as milk discard times and preslaughter withdrawal periods.
  • References sponsor information and related tolerances for each drug.
  • Includes specific regulations for Amoxicillin (§ 526.88), Ceftiofur (§ 526.313), Cephapirin benzathine (§ 526.363), Cephapirin sodium (§ 526.365), Cloxacillin benzathine (§ 526.464), Cloxacillin sodium (§ 526.465), Erythromycin (§ 526.820), Hetacillin (§ 526.1130), Novobiocin (§ 526.1590), Penicillin G procaine (§ 526.1696), and Penicillin G procaine and dihydrostreptomycin (§ 526.1697).
  • Emphasizes that Federal law restricts these drugs to use by or on the order of a licensed veterinarian.

Sections in Part 526

§ 526.1130

Hetacillin.

Specifications.(a) Each single-dose, 10-milliliter syringe contains hetacillin potassium equivalent of 62.5 milligrams (mg) ampicillin. Sponsor.(b) See No. 000010 in § 510.600(c) of this chapter. Related tolerances.(c) See § 556.316 of this chapter. Conditions of use in lactating cowsAmount(d) —(1) . Infuse the contents of one syringe (equivalent to 62.5 mg ampicillin) into each infected quarter. Repeat at 24-hour intervals for a maximum of 3 treatments. Indications for use.Streptococcus agalactiae, Streptococcus dysgalactiae, Staphylococcus aureus,Escherichia coli(2) For the treatment of acute, chronic, or subclinical mastitis in lactating cows caused by susceptible strains of and . Limitations.(3) Milk that has been taken from animals during treatment and for 72 hours (6 milkings) after the latest treatment must not be used for food. Treated animals must not be slaughtered for food until 10 days after the latest treatment. Federal law restricts this drug to use by or on the order of a licensed veterinarian. [57 FR 37335, Aug. 18, 1992, as amended at 75 FR 10168, Mar. 5, 2010; 84 FR 53311, Oct. 7, 2019; 86 FR 13186, Mar. 8, 2021]

§ 526.1590

Novobiocin.

Specifications.(a) Each single-dose, 10-milliliter syringe contains: (1) 150 milligrams (mg) of novobiocin equivalents as sodium novobiocin, or (2) 400 mg of novobiocin equivalents as sodium novobiocin. Sponsor.(b) See No. 054771 in § 510.600(c) of this chapter. Related tolerances.(c) See § 556.460 of this chapter. Conditions of use for syringe described in paragraph (a)(1) of this section in lactating cowsAmount(d) —(1) . Infuse the contents of one syringe (equivalent to 150 mg novobiocin) into each infected quarter after milking. Repeat treatment once after 24 hours. Do not milk for at least 6 hours after treatment. Indications for use.Staphylococcus aureus(2) For the treatment of mastitis caused by susceptible strains of in lactating cows. Limitations.(3) Milk taken from treated animals within 72 hours (6 milkings) after latest treatment should not be used for food. Do not slaughter treated animals for food for 15 days following latest treatment. Federal law restricts this drug to use by or on the order of a licensed veterinarian. Conditions of use for syringe described in paragraph (a)(2) of this section in dry cowsAmount(e) —(1) . Infuse the contents of one syringe…

§ 526.1696

Penicillin G procaine.

Specifications.(a) Each single-dose, 10-milliliter syringe contains penicillin G procaine equivalent to 100,000 units of penicillin G. (b) See Nos. 042791 and 061133 in § 510.600(c) of this chapter. Related tolerances.(c) See § 556.510 of this chapter. Conditions of use in lactating cowsAmount(d) —(1) . Infuse the contents of one 10-milliliter syringe (equivalent to 100,000 units penicillin G) into each infected quarter. Treatment may be repeated at 12-hour intervals for not more than 3 doses, as indicated by clinical response. Indications for use.Streptococcus agalactiae, S. dysgalactiae,S. uberus(2) For the treatment of mastitis caused by and in lactating cows. Limitations.(3) For intramammary infusion in lactating cows only. Discard all milk for 60 hours (5 milkings) after the latest treatment. Animals intended for human consumption must not be slaughtered within 3 days of latest treatment. For No. 042791: Federal law restricts this drug to use by or on the order of a licensed veterinarian. Conditions of use in dry cowsAmount(e) —(1) . Infuse the contents of one 10-milliliter syringe (equivalent to 100,000 units penicillin G) into each infected quarter at time of…

§ 526.1697

Penicillin G procaine and dihydrostreptomycin.

Specifications.(a) Each single-use, 10-milliliter syringe contains a suspension of: (1) Penicillin G procaine equivalent to 200,000 units penicillin G and dihydrostreptomycin sulfate equivalent to 300 milligrams dihydrostreptomycin; or (2) Penicillin G procaine equivalent to 1 million units penicillin G and dihydrostreptomycin sulfate equivalent to 1 gram dihydrostreptomycin. Sponsor.(b) See No. 042791 in § 510.600(c) of this chapter. Related tolerances.(c) See §§ 556.200 and 556.510 of this chapter. Conditions of use for syringe described in paragraph (a)(1) of this section in dry cowsAmount(d) —(1) . Infuse the contents of one syringe (equivalent to 200,000 units penicillin G and 300 milligrams dihydrostreptomycin) into each quarter at the last milking prior to drying off. Indications for use.Staphylococcus aureusStreptococcus agalactiae(2) For the treatment of subclinical mastitis in dairy cows at the time of drying off, specifically against infections caused by and . Limitations.(3) For use in dry cows only. Not to be used within 6 weeks of calving. Milk taken from cows within 24 hours (2 milkings) after calving must not be used for food. Animals infused with this drug…

§ 526.1698

Penicillin G procaine and novobiocin.

Specifications.(a) Each single-use, 10-milliliter syringe contains a suspension of: (1) Penicillin G procaine equivalent to 100,000 units penicillin G and 150 milligrams (mg) novobiocin as novobiocin sodium; or (2) Penicillin G procaine equivalent to 200,000 units penicillin G and 400 mg novobiocin as novobiocin sodium. Sponsor.(b) See No. 054771 in § 510.600(c) of this chapter. Related tolerances.(c) See §§ 556.460 and 556.510 of this chapter. Conditions of use for syringe described in paragraph (a)(1) of this section in lactating cowsAmount.(d) —(1) Infuse the contents of one syringe (equivalent to 100,000 units penicillin G and 150 mg novobiocin) into each infected quarter after milking. Repeat once after 24 hours. Indications for use.Staphylococcus aureus, Streptococcus agalactiae, Streptococcus dysgalactiae,Streptococcus uberis(2) For the treatment of mastitis caused by susceptible strains of and in lactating cows. Limitations.(3) For udder instillation in lactating cows only. Do not milk for at least 6 hours after treatment; thereafter, milk at regular intervals. Milk taken from treated animals within 72 hours (6 milkings) after the latest treatment must not be used…

§ 526.1810

Pirlimycin.

Specifications.(a) Each single-dose, 10-milliliter syringe contains 50 milligrams (mg) of pirlimycin (as pirlimycin hydrochloride). Sponsor.(b) See No. 054771 in § 510.600(c) of this chapter. Related tolerances.(c) See § 556.515 of this chapter. Conditions of use in lactating cowsAmount.(d) —(1) Infuse the contents of one syringe (50 mg pirlimycin) into each infected quarter. Daily treatment may be repeated at 24-hour intervals for up to 8 consecutive days. Indications for use.StaphylococcusStaphylococcus aureusStreptococcusStreptococcus agalactiaeStreptococcus dysgalactiaeStreptococcus uberis.(2) For the treatment of clinical and subclinical mastitis in lactating dairy cattle associated with species such as and species such as , , and Limitations.(3) Milk taken from animals during treatment and for 36 hours following the last treatment must not be used for food regardless of treatment duration. Following infusion twice at a 24-hour interval, treated animals must not be slaughtered for 9 days. Following any extended duration of therapy (infusion longer than twice at a 24-hour interval, up to 8 consecutive days), animals must not be slaughtered for 21 days. Federal law…

§ 526.313

Ceftiofur.

Specifications.(a) Each single-dose, 10-milliliter syringe contains: (1) 125 milligrams (mg) ceftiofur equivalents as the hydrochloride salt; or (2) 500 mg ceftiofur equivalents as the hydrochloride salt. Sponsor.(b) See No. 054771 in § 510.600(c) of this chapter. Related tolerances.(c) See § 556.113 of this chapter. Conditions of use for syringe described in paragraph (a)(1) of this section in lactating cowsAmount.(d) —(1) Infuse the contents of one syringe (125 mg ceftiofur equivalents) into each affected quarter. Repeat treatment in 24 hours. Once daily treatment may be repeated for up to 8 consecutive days. Indications for use.Streptococcus dysgalactiae,Escherichia coli;S. dysgalactiae(2) For the treatment of clinical mastitis associated with coagulase-negative staphylococci, and and the treatment of diagnosed subclinical mastitis associated with coagulase-negative staphylococci and . Limitations.(3) Milk taken from cows during treatment (a maximum of 8 daily infusions) and for 72 hours after the last treatment must not be used for human consumption. Following label use for up to 8 consecutive days, a 2-day preslaughter withdrawal period is required. Federal law…

§ 526.363

Cephapirin benzathine.

Specifications.(a) Each single-dose, 10-milliliter syringe contains 300 milligrams cephapirin activity (as cephapirin benzathine). Sponsor.(b) See No. 000010 in § 510.600(c) of this chapter. Related tolerances.(c) See § 556.115 of this chapter. Conditions of use in dry cowsAmount(d) —(1) . Infuse the contents of one syringe (300 mg cephapirin activity) into each quarter following last milking, but no later than 30 days before calving. Indications for use.Streptococcus agalactiaeStaphylococcus aureus,(2) For the treatment of mastitis caused by susceptible strains of and including penicillin-resistant strains. Limitations.(3) For use in dry cows only. Not to be used within 30 days of calving. Milk from treated cows must not be used for food during the first 72 hours after calving. Animals infused with this product must not be slaughtered for food until 42 days after the latest infusion. Federal law restricts this drug to use by or on the order of a licensed veterinarian. [43 FR 37174, Aug. 22, 1978, as amended at 53 FR 27851, July 25, 1988; 73 FR 12262, Mar. 7, 2008; 75 FR 10168, Mar. 5, 2010; 76 FR 17338, Mar. 29, 2011; 86 FR 13186, Mar. 8, 2021; 88 FR 16549, Mar. 20, 2023]

§ 526.365

Cephapirin sodium.

Specifications.(a) Each single-dose, 10-milliliter syringe contains 200 milligrams (mg) cephapirin sodium activity. Sponsor.(b) See No. 000010 in § 510.600(c) of this chapter. Related tolerances.(c) See § 556.115 of this chapter. Conditions of use in lactating cowsAmount.(d) —(1) Infuse the contents of one syringe (200 mg cephapirin activity) into each infected quarter immediately after the quarter has been completely milked out. Do not milk out for 12 hours. Repeat once only in 12 hours. Indications for use.Streptococcus agalactiaeStaphylococcus aureus(2) For the treatment of mastitis in lactating cows caused by susceptible strains of and including strains resistant to penicillin. Limitations.(3) Milk that has been taken from animals during treatment and for 96 hours after the last treatment must not be used for food. Treated animals must not be slaughtered for food until 4 days after the last treatment. Federal law restricts this drug to use by or on the order of a licensed veterinarian. [40 FR 57455, Dec. 10, 1975, as amended at 53 FR 27852, July 25, 1988. Redesignated at 63 FR 8349, Feb. 19, 1998; 65 FR 20733, Apr. 18, 2000; 73 FR 3181, Jan. 17, 2008; 75 FR 10168, Mar.…

§ 526.464

Cloxacillin benzathine.

Specifications.(a) Each single-dose, 7.5- or 10-milliliter syringe contains cloxacillin benzathine equivalent to 500 milligrams (mg) cloxacillin. Sponsor.(b) See No. 000010 in § 510.600(c) of this chapter. Related tolerances.(c) See § 556.165 of this chapter. Conditions of use in dry cowsAmount(d) —(1) . Infuse the contents of one syringe (equivalent to 500 mg cloxacillin) into each quarter immediately after last milking, but no later than 30 days before calving. Indications for use.Staphylococcus aureusStreptococcus agalactiae(2) For the treatment of mastitis caused by and including penicillin resistant strains in dairy cows during the dry period. Limitations.(3) Animals infused with this product must not be slaughtered for food until 30 days after the latest infusion. Federal law restricts this drug to use by or on the order of a licensed veterinarian. [86 FR 13186, Mar. 8, 2021]

§ 526.465

Cloxacillin sodium.

Specifications.(a) Each single-dose, 10-milliliter syringe contains cloxacillin sodium equivalent to 200 milligrams (mg) cloxacillin. Sponsor.(b) See No. 000061 in § 510.600(c) of this chapter. Related tolerances.(c) See § 556.165 of this chapter. Conditions of use in lactating cowsAmount.(d) —(1) Infuse the contents of one syringe (equivalent to 200 mg cloxacillin) into each infected quarter. Treatment should be repeated at 12-hour intervals for a total of 3 doses. Indications for use.Streptococcus agalactiaeStaphylococcus aureus,(2) For the treatment of mastitis in lactating cows due to and nonpenicillinase-producing strains. Limitations.(3) Milk taken from treated animals within 48 hours (4 milkings) after the latest treatment should not be used for food. Treated animals should not be slaughtered for food within 10 days after the latest treatment. Federal law restricts this drug to use by or on the order of a licensed veterinarian. [57 FR 37335, Aug. 18, 1992, as amended at 60 FR 55660, Nov. 2, 1995; 68 FR 44878, July 31, 2003. Redesignated at 85 FR 18120, Apr. 1, 2020. Redesignated and amended at 86 FR 13186, Mar. 8, 2021]

§ 526.820

Erythromycin.

Specifications.(a) (1) Each single-dose, 6-milliliter (mL) syringe contains 300 milligrams (mg) erythromycin (as the base). (2) Each single-dose, 12-mL syringe contains 600 mg erythromycin (as the base). Sponsors.(b) See Nos. 054771 and 061133 in § 510.600(c) of this chapter. Related tolerances.(c) See § 556.230 of this chapter. Conditions of use for syringe described in paragraph (a)(1) of this section in lactating cowsAmount.(d) —(1) Infuse the contents of one 6-mL syringe (300 mg erythromycin base) into each infected quarter. Repeat infusion at 12-hour intervals for a maximum of 3 infusions. Indications for use.Staphylococcus aureus, Streptococcus agalactiae, Streptococcus dysgalactiae,Streptococcus uberis(2) For the treatment of mastitis due to and in lactating cows. Limitations.(3) Milk taken from animals during treatment and for 36 hours (3 milkings) after the latest treatment must not be used for food. Federal law restricts this drug to use by or on the order of a licensed veterinarian. Conditions of use for syringe described in paragraph (a)(2) of this section in dry cowsAmount.(e) —(1) Infuse the contents of one 12-mL syringe (600 mg erythromycin base) into each…

§ 526.88

Amoxicillin.

Specifications.(a) Each single-dose, 10-milliliter syringe contains amoxicillin trihydrate equivalent to 62.5 milligrams (mg) amoxicillin. Sponsor.(b) See No. 000061 in § 510.600(c) of this chapter. Related tolerances.(c) See § 556.38 of this chapter. Conditions of use in lactating cowsAmount.(d) —(1) Infuse the contents of one syringe (equivalent to 62.5 mg amoxicillin) into each infected quarter every 12 hours for a maximum of 3 doses. Indications for use.Streptococcus agalactiaeStraphylococcus aureus(2) For the treatment of subclinical infectious bovine mastitis due to and (penicillin sensitive). Limitations.(3) Milk taken from animals during treatment and for 60 hours (5 milkings) after the last treatment must not be used for food. Treated animals must not be slaughtered for food purposes within 12 days after the last treatment. Federal law restricts this drug to use by or on the order of a licensed veterinarian. [57 FR 37334, Aug. 18, 1992, as amended at 60 FR 55660, Nov. 2, 1995; 68 FR 44878, July 31, 2003; 86 FR 13185, Mar. 8, 2021]

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