(a) Specifications. Type A medicated articles containing 1.12, 2.0, 11.2, or 50 percent coumaphos.

(b) Sponsor. See No. 000859 in § 510.600(c) of this chapter.

(c) Related tolerances. See § 556.168 of this chapter.

(d) Special considerations. Labeling shall bear the following caution statement: “The active ingredient coumaphos is a cholinesterase inhibitor. Do not use this product on animals simultaneously or within a few days before or after treatment with or exposure to cholinesterase-inhibiting drugs, pesticides, or chemicals.” Also, see § 500.25 of this chapter.

(e) Conditions of use - (1) Laying chickens - (i) Amount. Coumaphos 27.2 grams per ton (0.003 percent).

(ii) Indications for use. For control of capillary worm (Capillaria obsignata) and as an aid in control of common round worm (Ascaridia galli) and cecal worm (Heterakis gallinae).

(iii) Limitations. In Type C feed; administer continuously as the total feed ration for 14 days; when reinfection occurs, treatment may be repeated but not sooner than 3 weeks after the end of the previous treatment; do not feed to chickens within 10 days of vaccination or other conditions of stress; treatment of colored breeds of commercial layers should be avoided while in production since these breeds appear to be more sensitive to coumaphos than white breeds; as sole medication; medications in general should be avoided while birds are approaching peak production; such interruption of normal feeding practices may upset the flock and lower egg production; diagnosis by competent personnel is essential; flock condition and production records should be carefully evaluated prior to treatment.

(2) Replacement pullets - (i) Amount. Coumaphos 36.3 grams per ton (0.004 percent).

(ii) Indications for use. For control of capillary worm (Capillaria obsignata) and as an aid in control of common roundworm (Ascaridia galli) and cecal worm (Heterakis gallinae).

(iii) Limitations. In Type C feed; administer before the onset of production; diagnosis by competent personnel is essential; administer continuously as total feed ration for from 10 to 14 days; do not feed to chickens under 8 weeks of age nor within 10 days of vaccination or other conditions of stress; if birds are maintained on contaminated litter or exposed to infected birds, a second 10 to 14 day treatment is recommended but not sooner than 3 weeks after the end of the previous treatment; as sole medication; if reinfection occurs after production begins, repeat treatment as recommended for laying flocks.