#### § 558.198 Dichlorvos.

(a) *Specifications.* Each pound of Type A medicated article containing 3.1 or 9.6 percent dichlorvos.

(b) *Sponsor.* See No. 054628 in [§ 510.600(c) of this chapter](/on/2024-09-17/title-21/section-510.600#p-510.600(c)).

(c) *Related tolerances.* See [§ 556.180 of this chapter](/on/2024-09-17/title-21/section-556.180).

(d) *Special considerations.*

(1) Dichlorvos is to be included in meal or mash or mixed with feed in crumble form only after the crumble feed has been manufactured. Do not mix in feeds to be pelleted nor with pelleted feed. Do not soak the feed or administer as wet mash. Feed must be dry when administered. Do not use in animals other than swine. Do not allow fowl access to feed containing this preparation or to feces from treated animals.

(2) Dichlorvos is a cholinesterase inhibitor. Do not use this product in animals simultaneously or within a few days before or after treatment with or exposure to cholinesterase-inhibiting drugs, pesticides, or chemicals. If human or animal poisoning should occur, immediately consult a physician or a veterinarian. Atropine is antidotal.

(3) Labeling for Type A articles and Type B feeds must include a statement that containers or materials used in packaging such Type A articles and Type B feeds are not to be reused and all such packaging materials must be destroyed after the product has been used.

(e) *Conditions of use.* It is used in swine feed as follows:

| Dichlorvos grams/ton | Combination in grams/ton | Indications for use | Limitations | Sponsor |
| --- | --- | --- | --- | --- |
| (i) 348 | | Swine up to 70 pounds body weight: For the removal and control of mature, immature, and/or fourth-stage larvae of the whipworm (*Trichuris suis*), nodular worm (*Oesophagostomum* sp.), large roundworm (*Ascaris suum*) and the thick stomach worm (*Ascarops strongylina*) of the gastrointestinal tract. | Feed as sole ration for 2 consecutive days. For swine from 70 pounds to market weight, feed as sole ration at the rate of 8.4 pounds of feed per head until the medicated feed has been consumed. For boars, open or bred gilts, and sows, feed as sole ration at the rate of 4.2 pounds per head per day for 2 consecutive days. | 054628 |
| (ii) 479 | | Boars, open or bred gilts, and sows: For the removal and control of mature, immature, and/or fourth-stage larvae of the whipworm (*Trichuris suis*), nodular worm (*Oesophagostomum* sp.), large roundworm (*Ascaris suum*) and the thick stomach worm (*Ascarops strongylina*) of the gastrointestinal tract. | Feed as sole ration at the rate of 6 pounds per head for one feeding. | 054628 |
| (iii) 334 to 500 | | Pregnant swine: An aid in improving litter production efficiency by increasing pigs born alive, birth weights, survival to market, and rate of weight gain. Treatment also removes and controls mature, immature and/or fourth stage larvae of whipworm (*Trichuris suis*), nodular worm (*Oesophagostomum spp.*) large roundworm (*Ascaris suum*), and the thick stomach worm (*Ascarops strongylina*) occurring in the gastrointestinal tract of the sow or gilt. | Mix into a gestation feed to provide 1,000 milligrams per head daily during last 30 days of gestation. | 054628 |

[[84 FR 12497](https://www.federalregister.gov/citation/84-FR-12497), Apr. 2, 2019]