§ 520.905a Fenbendazole suspension. ( a ) *Specifications.* Each milliliter of suspension contains 100 milligrams (mg) fenbendazole for use as in paragraphs (e)(1), (2), (3), and (4) of this section; or 200 mg fenbendazole for use as in paragraphs (e)(5) and (6) of this section.
( b ) *Sponsor.* See No. 000061 in § 510.600(c) of this chapter.
( c ) *Related tolerances.* See § 556.275 of this chapter.
( d ) *Special considerations.* ( 1 ) See § 500.25 of this chapter.
( 2 ) Fenbendazole suspension 10 percent and approved forms of trichlorfon, when used concomitantly for treating the indications provided in paragraph (e) of this section and for treating infections of stomach bot as provided in § 520.2520, have been shown to be compatible and not to interfere with one another.
( e ) *Conditions of use* — ( 1 ) *Horses* — ( i ) *Amount.* Administer orally 5 mg per kilogram (/kg) (2.3 mg per pound (/lb)) for the control of large strongyles, small strongyles, and pinworms; 10 mg/kg for the control of ascarids.
( ii ) *Indications for use.* For the treatment and control of large strongyles (*Strongylus edentatus, S. equinus, S. vulgaris, Triodontophorus* species), small strongyles (*Cyathostomum* species, *Cylicocyclus* species, *Cylicostephanus* species, *Cylicodontophorus* species), pinworms (*Oxyuris equi*) and ascarids (*Parascaris equorum*).
( iii ) *Limitations.* Do not use in horses intended for human consumption.
( 2 ) *Beef and dairy cattle* — ( i ) *Amount.* Administer orally 2.3 mg/lb of body weight (5 mg/kg).
( ii ) *Indications for use.* For the treatment and control of: Lungworms: Adult (*Dictyocaulus viviparus*); Stomach worms: Adult brown stomach worms (*Ostertagia ostertagi*); adult and fourth-stage larvae barberpole worms (*Haemonchus contortus* and *H. placei*); adult and fourth-stage larvae small stomach worms (*Trichostrongylus axei*); Intestinal worms (adult and fourth-stage larvae): Hookworms (*Bunostomum phlebotomum*), thread-necked intestinal worms (*Nematodirus helvetianus*), small intestinal worms (*Cooperia punctata* and *C. oncophora*), bankrupt worms (*Trichostrongylus colubriformis*), and nodular worms (*Oesophagostomum radiatum*).
( iii ) *Limitations.* Milk taken from cows during treatment and for 48 hours after the last treatment must not be used for human consumption. Cattle must not be slaughtered for human consumption within 8 days following last treatment with this drug product. Not for use in beef calves less than 2 months of age, dairy calves, and veal calves. A withdrawal period has not been established for this product in preruminating calves.
( 3 ) *Beef cattle* — ( i ) *Amount.* Administer orally 4.6 mg/lb of body weight (10 mg/kg).
( ii ) *Indications for use.* For the treatment and control of stomach worms (fourth-stage inhibited larvae/type II ostertagiasis), *Ostertagia ostertagi,* and tapeworms, *Moniezia benedeni.*
( iii ) *Limitations.* Cattle must not be slaughtered for human consumption within 8 days following last treatment with this drug product. Not for use in beef calves less than 2 months of age, dairy calves, and veal calves. A withdrawal period has not been established for this product in preruminating calves. Federal law restricts this drug to use by or on the order of a licensed veterinarian.
( 4 ) *Goats* — ( i ) *Amount.* Administer orally 2.3 mg/lb of body weight (5 mg/kg).
( ii ) *Indications for use.* For the treatment and control of stomach worms (adults) *Haemonchus contortus* and *Teladorsagia circumcincta.*
( iii ) *Limitations.* Goats must not be slaughtered for human consumption within 6 days following last treatment with this drug product. Because a milk discard time has not been established, do not use in lactating goats.
( 5 ) *Chickens* — ( i ) *Amount.* Administer orally via drinking water at a daily dose of 1 mg/kg body weight (0.454 mg/lb) for 5 consecutive days.
( ii ) *Indications for use.* For the treatment and control of adult *Ascaridia galli* in broiler chickens and replacement chickens, and for the treatment and control of adult *A. galli* and *Heterakis gallinarum* in breeding chickens and laying hens.
( 6 ) *Swine, except for nursing piglets* — ( i ) *Amount.* Administer orally via the drinking water at a daily dose of 2.2 mg/kg of body weight (1.0 mg/lb) for 3 consecutive days.
( ii ) *Indications for use.* For the treatment and control of: Lungworms: Adult *Metastrongylus apri,* Adult *Metastrongylus pudendotectus;* Gastrointestinal worms: Adult and larvae (L3, L4 stages, liver, lung, intestinal forms) large roundworms (*Ascaris suum*), Adult nodular worms (*Oesophagostomum dentatum, O. quadrispinulatum*), Adult small stomach worms (*Hyostrongylus rubidus*), Adult and larvae (L2, L3, L4 stages—intestinal mucosal forms) whipworms (*Trichuris suis*); and Kidney worms: Adult and larvae *Stephanurus dentatus.*
( iii ) *Limitations.* Swine intended for human consumption must not be slaughtered within 2 days from the last treatment.
[42 FR 59069, Nov. 15, 1977; 43 FR 12311, Mar. 24, 1978. Redesignated at 44 FR 1375, Jan. 5, 1979, and amended at 46 FR 29464, June 2, 1981; 47 FR 15327, Apr. 9, 1982; 48 FR 42809, Sept. 20, 1983; 49 FR 1983, Jan. 17, 1984; 53 FR 40058, Oct. 13, 1988; 59 FR 26943, May 25, 1994; 61 FR 29478, June 11, 1996; 63 FR 63983, Nov. 18, 1998; 66 FR 47960, Sept. 17, 2001; 68 FR 26205, May 15, 2003; 74 FR 17770, Apr. 17, 2009; 74 FR 61516, Nov. 25, 2009; 76 FR 17336, Mar. 29, 2011; 80 FR 76386, Dec. 9, 2015; 81 FR 22523, Apr. 18, 2016; 86 FR 14818, Mar. 19, 2021; 86 FR 61684, Nov. 8, 2021; 87 FR 58961, Sept. 29, 2022]