21 CFR 558.258 - Fenbendazole.

View all text of Subpart B [§ 558.55 - § 558.680]

§ 558.258 - Fenbendazole.

(a) Specifications. Type A medicated articles: 4 percent (18.1 grams per pound (g/lb)), 8 percent (36.2 g/lb), and 20 percent (90.7 g/lb) fenbendazole.

(b) Sponsor. See No. 000061 in § 510.600(c) of this chapter.

(d) Special considerations. See § 500.25 of this chapter.

(e) Conditions of use—(1) Turkeys.

Amount fenbendazole in grams per ton	Combination in grams per ton	Indications for use	Limitations	Sponsor	(i) 14.5		Growing turkeys: For the treatment and control of gastrointestinal worms: roundworms, adults and larvae (Ascaridia dissimilis); cecal worms, adults and larvae (Heterakis gallinarum), an important vector of Histomonas meleagridis (Blackhead)	Feed continuously as the sole ration for 6 days. For growing turkeys only	000061	(ii) [Reserved]

(2) Swine.

Fenbendazole grams per ton	Combination grams per ton	Indications for use	Limitations	Sponsor	(i) 10 to 300		Swine: For the treatment and control of Lungworms: adult (Metastrongylus apri and M. pudendotectus); Gastrointestinal worms: adult and larvae (L3, 4 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, 3, 4 stages—intestinal mucosal forms) whipworms (Trichuris suis); and Kidney worms: adult and larvae (Stephanurus dentatus)	Feed as the sole ration to provide 9 mg/kg of body weight (4.08 mg/lb) over a period of 3 to 12 consecutive days. Swine must not be slaughtered for human consumption within 4 days following last treatment with this drug product	000061	(ii) 10 to 300 (to provide 9 mg/kg of body weight)	Bacitracin methylenedisalicylate, 10 to 30	Growing/finishing swine: For the removal and control of adult stage lungworms (Metastrongylus apri and M. pudendotectus); adult and larvae (L3, 4 stages—liver, lung, intestinal forms) large roundworms (Ascaris suum); adult stage nodular worms (Oesophagostomum dentatum, O. quadrispinulatum); adult stage small stomach worms (Hyostrongylus rubidus); adult and larvae (L2, 3, 4 stages—intestinal mucosal forms) whipworms (Trichuris suis); adult and larvae kidney worms (Stephanurus dentatus); and for increased rate of weight gain and improved feed efficiency	Feed as the sole ration. Under conditions of continued exposure to parasites, retreatment may be needed after 4 to 6 weeks. Bacitracin methylenedisalicylate as provided by No. 054771 in § 510.600(c) of this chapter	054771	(iii) 10 to 300 (to provide 9 mg/kg of body weight)	Bacitracin methylenedisalicylate, 250	1. Growing/finishing swine: For the removal and control of adult stage lungworms (Metastrongylus apri and M. pudendotectus); adult and larvae (L3, 4 stages—liver, lung, intestinal forms) large roundworms (Ascaris suum); adult stage nodular worms (Oesophagostomum dentatum, O. quadrispinulatum); adult stage small stomach worms (Hyostrongylus rubidus); adult and larvae (L2, 3, 4 stages—intestinal mucosal forms) whipworms (Trichuris suis); adult and larvae kidney worms (Stephanurus dentatus); and for control of swine dysentery associated with Treponema hyodysenteriae on premises with a history of swine dysentery, but where signs of disease have not yet occurred; or following an approved treatment of the disease condition	1. Growing/finishing swine: Feed as sole ration. Not for use in growing and finishing swine that weigh more than 250 lbs. Diagnosis of swine dysentery should be confirmed by a veterinarian when results are not satisfactory. Under conditions of continued exposure to parasites, retreatment may be needed after 4 to 6 weeks. Bacitracin methylenedisalicylate as provided by No. 054771 in § 510.600(c) of this chapter	054771			2. Pregnant sows: For the removal and control of adult stage lungworms (Metastrongylus apri and M. pudendotectus); adult and larvae (L3, 4 stages—liver, lung, intestinal forms) large roundworms (Ascaris suum); adult stage nodular worms (Oesophagostomum dentatum, O. quadrispinulatum); adult stage small stomach worms (Hyostrongylus rubidus); adult and larvae (L2, 3, 4 stages—intestinal mucosal forms) whipworms (Trichuris suis); adult and larvae kidney worms (Stephanurus dentatus); for control of clostridial enteritis in suckling pigs caused by Clostridium perfringens	2. Pregnant sows: Feed as sole ration. Diagnosis of clostridial enteritis should be confirmed by a veterinarian when results are not satisfactory. Under conditions of continued exposure to parasites, retreatment may be needed after 4 to 6 weeks. Bacitracin methylenedisalicylate as provided by No. 054771 in § 510.600(c) of this chapter.

(3) Cattle.

Fenbendazole grams per ton	Indications for use	Limitations	Sponsor	(i) 200 to 1,000	Dairy and beef cattle: 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), fourth-stage larvae barberpole worms (H. placei), and 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)	Feed as the sole ration for 1 day to provide 5 mg/kg body weight (2.27 mg/lb). Milk taken during treatment and for 60 hours after the last treatment must not be used for human consumption. Cattle must not be slaughtered for human consumption within 13 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 pre-ruminating calves	000061	(ii) [Reserved]

(iii) Top dress medicated feed—(A) Proprietary formulas. The following feed can be manufactured only per an approved proprietary formula and specifications:

Fenbendazole concentration	Indications for use	Limitations	Sponsor	(1) 2.27 g/lb	Beef and dairy cattle: 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), fourth-stage larvae barberpole worms (H. placei), and 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)	Feed as a top dress for 1 day to provide 5 mg/kg body weight (2.27 mg/lb). Milk taken during treatment and for 60 hours after the last treatment must not be used for human consumption. Cattle must not be slaughtered for human consumption within 13 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 pre-ruminating calves	000061	(2) [Reserved]

(B) [Reserved]

(iv) Free-choice medicated feeds—(A) Proprietary formulas (21 CFR 510.455(e)(2)). The following feeds can be manufactured only per an approved proprietary formula and specifications:

Fenbendazole concentration	Indications for use	Limitations	Sponsor	(1) 12,100 g/ton mineral	Beef cattle on pasture: 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), fourth-stage larvae barberpole worms (H. placei), and 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)	Feed free-choice at the rate of 0.0375 lb per 100 pounds of body weight over a 3- to 6-day period to provide a total of 2.27 mg fenbendazole per pound of body weight. Not for use in dairy cattle. Beef cattle must not be slaughtered for human consumption within 13 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 pre-ruminating calves	000061	(2) 2.27 g/lb mineral	Beef cattle on pasture: 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), fourth-stage larvae barberpole worms (H. placei), and 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)	Feed free-choice at the rate of 0.10 lb (1.6 oz) per 100 pounds of body weight over a 3- to 6-day period, to deliver a total of 2.27 mg fenbendazole per pound of body weight. Not for use in dairy cattle. Beef cattle must not be slaughtered for human consumption within 13 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 pre-ruminating calves	000061	(3) 750 mg/lb of protein block (to provide 5 mg/kg body weight (2.27 mg/lb))	Beef cattle: 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), fourth-stage larvae barberpole worms (H. placei), and 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)	Feed free choice at a rate of 0.1 pound of block per 100 pounds of body weight per day for 3 days to deliver a total of 2.27 mg fenbendazole per pound of body weight. Cattle must not be slaughtered for human consumption within 16 days following last treatment with this drug product. Not for use in female dairy cattle 20 months of age or older, including dry dairy cows. Use in these cattle may cause drug residues in milk and/or in calves born to these cows or heifers. 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 pre-ruminating calves	000061	(4) 750 mg/lb of molasses block (to provide 5 mg/kg body weight (2.27 mg/lb))	Beef cattle: 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), fourth-stage larvae barberpole worms (H. placei), and 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)	Feed free choice at a rate of 0.1 pound of block per 100 pounds of body weight per day for 3 days to deliver a total of 2.27 mg fenbendazole per pound of body weight. Cattle must not be slaughtered for human consumption within 11 days following last treatment with this drug product. Not for use in female dairy cattle 20 months of age or older, including dry dairy cows. Use in these cattle may cause drug residues in milk and/or in calves born to these cows or heifers. 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 pre-ruminating calves	000061

(B) Published formulas (§ 510.455(e)(1) of this chapter). The following feeds can be manufactured only per one of the formulas and specifications published below:

(1) Amount. 5 mg/kg body weight (2.27 mg/lb), including the following formulations:

Ingredient 1	Percent	International Feed No.	(i) Free-choice, dry Type C feed:			Salt (sodium chloride)	59.00	6-04-152	Monosodium phosphate	31.16	6-04-288	Dried cane molasses	3.12	4-04-695	Zinc sulfate	0.76	6-05-556	Copper sulfate	0.45	6-01-720	Fenbendazole 20% Type A article	5.51	n/a	(ii) Free-choice, dry Type C feed:			Salt (sodium chloride)	35.93	6-04-152	Dicalcium phosphate (18.5% P)	32.44	6-00-080	Calcium carbonate (38% Ca)	15.93	6-01-069	Magnesium oxide (56% Mg)	10.14	6-02-756	Zinc sulfate	1.47	6-05-556	Mineral oil	1.00	8-03-123	Dried cane molasses (46% sugars)	0.98	4-04-695	Potassium iodide	0.01	6-03-759	Fenbendazole 20% Type A article	2.10	n/a	(iii) Free-choice, liquid Type C feed 2:			Cane molasses 3	80.902	4-13-251	Water	9.36	n/a	Urea solution, 55%	7.05	5-05-707	Phosphoric acid 75% (feed grade)	2.00	6-03-707	Xantham gum	0.20	8-15-818	Trace minerals 4	0.20	n/a	Vitamin premix 4	0.01	n/a	Fenbendazole 20% Type A article	0.278	n/a

1 Formulation modifications require FDA approval prior to marketing. Selenium is not approved for use in the liquid, free-choice formulations described in paragraph (e)(3)(iv)(B) of this section. Free-choice cattle feeds containing selenium must comply with published regulations (see 21 CFR 573.920).

2 The labeling for the liquid free-choice Type C medicated feed must bear an expiration date of 12 weeks after the date of manufacture.

3 The percentage of cane molasses and water in the formulation may be adjusted as needed to bring the brix value of the molasses to the industry standard of 79.5 brix.

4 The contents of any added vitamin and trace mineral may be varied; however, they should be comparable to those used by the manufacturer for other free-choice cattle feeds.

(2) Indications for use. As in paragraph (e)(3)(i) of this section.

(3) Limitations. Feed a total of 5 mg of fenbendazole per kg (2.27 mg/lb) of body weight to cattle over a 3- to 6-day period. Milk taken during treatment and for 60 hours after the last treatment must not be used for human consumption. Cattle must not be slaughtered for human consumption within 13 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 pre-ruminating calves.

(4) Horses.

Fenbendazole grams per ton	Indications for use	Limitations	Sponsor	(i) 4,540	5 mg/kg body weight (2.27 mg/lb) for the control of large strongyles (Strongylus edentatus, S. equinus, S. vulgaris, Triodontophorus spp.), small strongyles (Cyathostomum spp., Cylicocyclus spp., Cylicostephanus spp.), and pinworms (Oxyuris equi); 10 mg/kg body weight (4.54 mg/lb) for the control of ascarids (Parascaris equorum)	Feed at the rate of 0.1 lb of feed per 100 lb of body weight to provide 2.27 mg fenbendazole/lb of body weight in a 1-day treatment or 0.2 lb of feed per 100 lb of body weight to provide 4.54 mg fenbendazole/lb of body weight in a 1-day treatment. All horses must be eating normally to ensure that each animal consumes an adequate amount of the medicated feed. Do not use in horses intended for human consumption	000061	(ii) [Reserved]

(5) Zoo and wildlife animals.

Species/Class	Fenbendazole grams per ton	Indications for use	Limitations	Sponsor	(i) Feral swine (Sus scrofa):	90 to 325	For the treatment and control of kidney worm (Stephanurus dentatus), roundworm (Ascaris suum), nodular worm (Oesophagostomum dentatum)	Use as a complete feed at a rate to provide 3 mg/kg/day for 3 consecutive days. Prior withdrawal of feed or water is not necessary. Retreatment may be required in 6 weeks. Do not use 14 days before or during the hunting season	000061	(ii) Ruminants (subfamily Antilopinae, Hippotraginae, Caprinae)	50 to 300	For the treatment and control of small stomach worm (Trichostrongylus spp.), thread necked intestinal worm (Nematodirus spp.), barberpole worm (Haemonchus spp.), whipworm (Trichuris spp.)	Use as a complete feed at a rate to provide 2.5 mg/kg/day for 3 consecutive days. Prior withdrawal of feed or water is not necessary. Retreatment may be required in 6 weeks. Do not use 14 days before or during the hunting season	000061	(iii) Rocky mountain bighorn sheep (Ovis c. canadensis)	375 to 1,000	For the treatment and control of Protostrongylus spp.	Use as a complete feed at a rate to provide 10 mg/kg/day for 3 consecutive days. Prior withdrawal of feed or water is not necessary. Retreatment may be required in 6 weeks. Do not use 14 days before or during the hunting season	000061	(iv) Wild quail	90.7	For the treatment and control of Gastrointestinal worms: cecal worms (Aulonocephalus spp.)	Feed for 21 consecutive days. Prior withdrawal of feed is not necessary	000061

(6) Fenbendazole may also be used in combination with:

(i) [Reserved]

(ii) Lincomycin as in § 558.325.

[66 FR 58935, Nov. 26, 2001, as amended at 68 FR 34534, June 10, 2003; 72 FR 66046, Nov. 27, 2007; 73 FR 58873, Oct. 8, 2008; 74 FR 61517, Nov. 25, 2009; 79 FR 13545, Mar. 11, 2014; 81 FR 17609, Mar. 30, 2016; 81 FR 95005, Dec. 27, 2016; 84 FR 12499, Apr. 2, 2019; 86 FR 14822, Mar. 19, 2021; 87 FR 58964, Sept. 29, 2022; 88 FR 14904, Mar. 10, 2023; 89 FR 85428, Oct. 28, 2024]