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U.S. Department of Health and Human Services

CFR - Code of Federal Regulations Title 21

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The information on this page is current as of Oct 01, 2021.

For the most up-to-date version of CFR Title 21, go to the Electronic Code of Federal Regulations (eCFR).

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Help | More About 21CFR
[Code of Federal Regulations]
[Title 21, Volume 6]
[CITE: 21CFR520.596]



TITLE 21--FOOD AND DRUGS
CHAPTER I--FOOD AND DRUG ADMINISTRATION
DEPARTMENT OF HEALTH AND HUMAN SERVICES
SUBCHAPTER E - ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS

PART 520 -- ORAL DOSAGE FORM NEW ANIMAL DRUGS

Sec. 520.596 Dichlorvos powder.

(a) Specifications - (1) Each 2-ounce packet contains 2.27 grams (4 percent) dichlorvos.

(2) Each milligram of powder contains 2.27 milligrams (mg) dichlorvos.

(b) Sponsor. See No. 069043 in § 510.600(c) of this chapter for use of the product described in paragraph (a)(1) of this section as in paragraph (d)(1) of this section and the product described in paragraph (a)(2) of this section as in paragraph (d)(2) of this section.

(c) Related tolerances. See § 556.180 of this chapter.

(d) Conditions of use - (1) Swine (adult gilts, sows, and boars) - (i) Amount. Add powder to the indicated amount of feed and administered shortly after mixing, as follows:

Weight of animal in pounds Pounds of feed to
be mixed with
each 0.08
ounce of
dichlorvos
Pounds of mixed
feed to be
administered to
each pig as a
single treatment
Number of pigs
to be treated
per 0.08
ounce of
dichlorvos
20-3040.3312
31-4050.569
41-6061.006
61-8051.005
81-10041.004
164.004

(ii) Indications for use. For the removal and control of sexually mature (adult), sexually immature and/or 4th stage larvae of the whipworm (Trichuris suis ), nodular worms (Oesophagostomum spp.), large round-worm (Ascaris suum ), and the mature thick stomach worm (Ascarops strongylina ) occurring in the lumen of the gastrointestinal tract of pigs, boars, and open or bred gilts and sows.

(iii) Limitations. Do not use this product on animals either simultaneously or within a few days before or after treatment with or exposure to cholinesterase inhibiting drugs, pesticides, or chemicals. The preparation should be mixed thoroughly with the feed on a clean, impervious surface. Do not allow swine access to feed other than that containing the preparation until treatment is complete. Do not treat pigs with signs of scours until these signs subside or are alleviated by proper medication. Resume normal feeding schedule afterwards. Swine may be retreated in 4 to 5 weeks.

(2) Horses - (i) Amount. Administer in the grain portion of the ration at a dosage of 14.2 to 18.5 mg per pound of body weight as a single dose. Administered at one-half of the single recommended dosage and repeated 8 to 12 hours later in the treatment of very aged, emaciated, or debilitated subjects or those reluctant to consume medicated feed. In suspected cases of severe ascarid infection sufficient to cause concern over mechanical blockage of the intestinal tract, the split dosage should be used.

(ii) Indications for use. For the removal and control of bots (Gastrophilus intestinalis, G. nasalis ), large strongyles (Strongylus vulgaris, S. equinus, S. edentatus ), small strongyles (of the genera Cyathostomum, Cylicocercus, Cylicocyclus, Cylicodontophorus, Triodontophorus, Poteriostomum, Gyalocephalus ), pinworms (Oxyuris equi ), and large roundworm (Parascaris equorum ) in horses including ponies and mules. Not for use in foals (sucklings and young weanlings).

(iii) Limitations. Do not use in horses which are severely debilitated, suffering from diarrhea or severe constipation, infectious disease, toxemia, or colic. Do not administer in conjunction with or within 1 week of administration of muscle relaxant drugs, phenothiazine derived tranquilizers or central nervous system depressant drugs. Horses should not be subjected to insecticide treatment for 5 days prior to or after treating with the drug. Do not administer to horses afflicted with chronic alveolar emphysema (heaves) or related respiratory conditions. The product is a cholinesterase inhibitor and should not be used simultaneously or within a few days before or after treatment with or exposure to cholinesterase inhibiting drugs, pesticides or chemicals. Do not use in animals other than horses, ponies, and mules. Do not use in horses, ponies, and mules intended for food purposes. Do not allow fowl access to feed containing this preparation or to fecal excrement from treated animals.

[83 FR 48944, Sept. 28, 2018]

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