title: Efficacy of different dosage levels and administration routes of tilmicosin in a natural outbreak of infectious bovine keratoconjunctivitis (pinkeye).
abstract: A total of 120 purebred Hereford cattle were selected from a herd on a ranch in Argentina that had a severe outbreak of infectious bovine keratoconjunctivitis (IBK, pinkeye) caused by Moraxella bovis. The animals were separated into six treatment groups: a nonmedicated control group, a group that received oxytetracycline at 300 mg injected intrapalpebrally, and four groups that received tilmicosin (Micotil, Elanco Animal Health, Indianapolis, IN; one group injected intrapalpebrally at 300 mg and three groups injected subcutaneously at 2.5, 5, and 10 mg/kg body weight, respectively). Animals were individually observed for resolution of lesions associated with IBK (ocular discharge, blepharospasin, and corneal lesions) every 7 days for 3 weeks. Corneal improvement was significantly better (P< or = .05) for all doses and for either route of injection for tilmicosin compared with no treatment or treatment with oxytetracycline. Tilmicosin given subcutaneously demonstrated a significant (P < or = .05) dose response for overall improvement (one or more score improved, none worsened). Tilmicosin given subcutaneously at 10 mg/kg was significantly more effective than tilmicosin at 2.5 mg/kg, oxytetracycline, and no treatment. Results for tilmicosin at 5 mg/kg were numerically better than no treatment, and tilmicosin at 10 mg/kg was numerically better than the drug given by intrapalpebral injection. Tilmicosin given by subcutaneous injection at 5 or 10 mg/kg was effective against IBK under the conditions of this study.
authors.affiliation: Estacion Experimental Marcos Juarez, INTA, Córdoba, Argentina.
authors.forename: Gustavo C
authors.initials: GC
authors.lastname: Zielinski
authors.forename: Hernán G
authors.initials: HG
authors.lastname: Piscitelli
authors.forename: Hernán
authors.initials: H
authors.lastname: Perez-Monti
authors.forename: Larry A
authors.initials: LA
authors.lastname: Stobbs
authors.forename: Alan G
authors.initials: AG
authors.lastname: Zimmermann
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D002417:Cattle; D002418:Cattle Diseases / Q000188:drug therapy*; D004196:Disease Outbreaks / Q000662:veterinary*; D004305:Dose-Response Relationship, Drug; D004333:Drug Administration Routes; D007639:Keratoconjunctivitis, Infectious / Q000188:drug therapy*; D008297:Male; D010865:Pilot Projects; D015645:Tylosin / Q000031:analogs & derivatives* / Q000627:therapeutic use
chemical_list: D000900:Anti-Bacterial Agents; C052319:tilmicosin; D015645:Tylosin