Bird · Bubo virginianus · typical adult weight 0.90–1.80 kg
Fenbendazole is dosed at 25 mg/kg PO once in great horned owls, per Samour, Avian Medicine, 3rd Ed. (raptor formulary appendix), p.666. Row as printed binds this dose to raptors on its own line: "Fenbendazole Panacur 2.5% or 10% Raptors PO 100 mg/kg once Ascarids, some microfilariae, capillariasis, other". Located by line-level extraction and then read on the page; the species binding is the row's own species column, not text proximity. | REDUCED 100 -> 25 mg/kg ON 2026-08-20 after independent cross-book review: raptor text p.325 "Fenbendazole 25 mg/kg either once or SID for 3-5 days ... Possible toxicity in vultures?"; BSAVA raptor p.65 "Fenbendazole is considered to be toxic in vultures"; Plumb's p.534 "NOTE: Fenbendazole may cause severe toxicity in some birds". Primary toxicity reports: Weber MA et al., J Am Vet Med Assoc 2002;221:417-419 (bone marrow hypoplasia, five painted storks); Gozalo AS et al., J Am Assoc Lab Anim Sci 2006;45:63-66 (mortality in pigeons); Bonar CJ et al., J Avian Med Surg 2003;17:16 (two vulture species); Howard LL et al., J Avian Med Surg 2002;16:203-210. | PRIMARY TOXICITY REPORTS VERIFIED IN PUBMED 2026-08-20, retrieved independently of the handbook reference list that named them: Gozalo AS, Schwiebert RS, Lawson GW. "Mortality associated with fenbendazole administration in pigeons (Columba livia)." J Am Assoc Lab Anim Sci 2006;45(6):63-66. PMID 17089995 — https://pubmed.ncbi.nlm.nih.gov/17089995/ . Weber MA, Terrell SP, Neiffer DL, Miller MA, Mangold BJ. "Bone marrow hypoplasia and intestinal crypt cell necrosis associated with fenbendazole […]" J Am Vet Med Assoc 2002;221(3):417-419. PMID 12164542 — https://pubmed.ncbi.nlm.nih.gov/12164542/ . Both titles state the harm directly; neither paper was read in full, so this establishes that the reports exist and what they report, not their dose-response detail. | RAPTOR-SPECIFIC LITERATURE RETRIEVED 2026-08-20: Al-Timimi F, Nolosco P, Al-Timimi B. "Incidence and treatment of serratospiculosis in falcons from Saudi Arabia." Vet Rec 2009;165(14):408-409. doi:10.1136/vr.165.14.408. PMID 19801594 — https://pubmed.ncbi.nlm.nih.gov/19801594/ (30 mg/kg PO 5-8 days effective, no side effects). Doss GA, Mans C, Johnson L, Pinkerton ME, Hardie RJ, Sladky KK. "Diagnosis and management of inflammatory bowel disease in a harpy eagle (Harpia harpyja) with suspected fenbendazole toxicosis." J Am Vet Med Assoc 2018;252(3):336-342. PMID 29346050 — https://pubmed.ncbi.nlm.nih.gov/29346050/ . Both abstracts read in full.. Fenbendazole is used in great horned owls for Ascarids, some microfilariae, capillariasis, other. Routes documented in great horned owls: PO. A typical adult great horned owl weighs 0.90–1.80 kg. ExoticRx lists 1 cited dose rule for Fenbendazole in great horned owls, drawn from published veterinary references. Verify against current literature before clinical use.
US trade names: Panacur
| Route | Dose | Frequency | Duration | Indication | Evidence | Source |
|---|---|---|---|---|---|---|
| PO | 25 mg/kg | once | 3-5 days as printed | Ascarids, some microfilariae, capillariasis, other | Moderate | Samour, Avian Medicine, 3rd Ed. (raptor formulary appendix), p.666. Row as printed binds this dose to raptors on its own line: "Fenbendazole Panacur 2.5% or 10% Raptors PO 100 mg/kg once Ascarids, some microfilariae, capillariasis, other". Located by line-level extraction and then read on the page; the species binding is the row's own species column, not text proximity. | REDUCED 100 -> 25 mg/kg ON 2026-08-20 after independent cross-book review: raptor text p.325 "Fenbendazole 25 mg/kg either once or SID for 3-5 days ... Possible toxicity in vultures?"; BSAVA raptor p.65 "Fenbendazole is considered to be toxic in vultures"; Plumb's p.534 "NOTE: Fenbendazole may cause severe toxicity in some birds". Primary toxicity reports: Weber MA et al., J Am Vet Med Assoc 2002;221:417-419 (bone marrow hypoplasia, five painted storks); Gozalo AS et al., J Am Assoc Lab Anim Sci 2006;45:63-66 (mortality in pigeons); Bonar CJ et al., J Avian Med Surg 2003;17:16 (two vulture species); Howard LL et al., J Avian Med Surg 2002;16:203-210. | PRIMARY TOXICITY REPORTS VERIFIED IN PUBMED 2026-08-20, retrieved independently of the handbook reference list that named them: Gozalo AS, Schwiebert RS, Lawson GW. "Mortality associated with fenbendazole administration in pigeons (Columba livia)." J Am Assoc Lab Anim Sci 2006;45(6):63-66. PMID 17089995 — https://pubmed.ncbi.nlm.nih.gov/17089995/ . Weber MA, Terrell SP, Neiffer DL, Miller MA, Mangold BJ. "Bone marrow hypoplasia and intestinal crypt cell necrosis associated with fenbendazole […]" J Am Vet Med Assoc 2002;221(3):417-419. — . Both titles state the harm directly; neither paper was read in full, so this establishes that the reports exist and what they report, not their dose-response detail. | RAPTOR-SPECIFIC LITERATURE RETRIEVED 2026-08-20: Al-Timimi F, Nolosco P, Al-Timimi B. "Incidence and treatment of serratospiculosis in falcons from Saudi Arabia." Vet Rec 2009;165(14):408-409. . — (30 mg/kg PO 5-8 days effective, no side effects). Doss GA, Mans C, Johnson L, Pinkerton ME, Hardie RJ, Sladky KK. "Diagnosis and management of inflammatory bowel disease in a harpy eagle (Harpia harpyja) with suspected fenbendazole toxicosis." J Am Vet Med Assoc 2018;252(3):336-342. — . Both abstracts read in full. |
Need the exact dose for your patient?
These ranges are per kg. Enter your great horned owl's weight to get the precise dose and draw-up volume — unit and concentration math done for you.
Binds to beta-tubulin, inhibiting microtubule polymerization in parasites. Disrupts energy metabolism and cell division.
Very wide safety margin. Rarely causes vomiting or diarrhea. Safe in pregnant animals at standard doses. Must be given for multiple consecutive days for efficacy.
Species-specific contraindications and adverse-reaction reports for great horned owls may differ from canine / feline reference data — consult the primary citations listed with each rule.
Fenbendazole dose range in great horned owls, with cited source references: PO 25 mg/kg once. Reference ranges from cited sources — verify against current literature before clinical use.
Documented routes for Fenbendazole in great horned owls: PO.
Cited course lengths for Fenbendazole in great horned owls include: 3-5 days as printed. Duration depends on the indication — match it to the specific dose rule in the table above.
Fenbendazole is indicated in great horned owls for: Ascarids, some microfilariae, capillariasis, other.
These are general warnings for Fenbendazole across species; consult the great horned owl dosing table above for species-specific guidance. Very wide safety margin. Rarely causes vomiting or diarrhea. Safe in pregnant animals at standard doses. Must be given for multiple consecutive days for efficacy.
Why a species-specific page? Fenbendazole pharmacokinetics differ across species: dose ranges, intervals, and route preferences are not interchangeable. Cross-extrapolation from canine doses is unsafe in great horned owls — the rules above are the citations specific to this species, not generic recommendations.
Sourced from published veterinary references; awaiting credentialed clinical reviewer. See our editorial process. Reference only — not veterinary advice.