title: Conductive hearing loss in bighorn sheep.
abstract: In January 1993 we simulated a conductive hearing loss in three Mexican bighorn sheep (Ovis canadensis mexicana) by placing bone wax or saline solution in their ear canals. Our objective was to test whether lesions of the external auditory canal caused by psoroptic mites (Psoroptes ovis) may lead to conductive hearing loss in bighorn sheep. We assessed the effects of these manipulations using the auditory brainstem response test. Placing saline solution in the external auditory canal, which loads the tympanic membrane, had a more dramatic effect on the auditory brainstem response than did bone wax. We propose that decreased hearing sensitivity or alterations in resonance characteristics of the external auditory canal, due to psoroptic scabies lesions, may make bighorn sheep more susceptible to predation.
authors.affiliation: Speech and Hearing Science, University of Arizona, Tucson 85721, USA.
authors.forename: L W
authors.initials: LW
authors.lastname: Norrix
authors.forename: D W
authors.initials: DW
authors.lastname: DeYoung
authors.forename: P R
authors.initials: PR
authors.lastname: Krausman
authors.forename: R C
authors.initials: RC
authors.lastname: Etchberger
authors.forename: T J
authors.initials: TJ
authors.lastname: Glattke
mesh_terms: D000818:Animals; D000835:Animals, Wild; D001300:Audiometry, Evoked Response / Q000662:veterinary; D004338:Drug Combinations; D004424:Ear Canal / Q000473:pathology; D016057:Evoked Potentials, Auditory, Brain Stem; D006314:Hearing Loss, Conductive / Q000469:parasitology / Q000503:physiopathology / Q000662:veterinary*; D008924:Mite Infestations / Q000150:complications / Q000662:veterinary*; D010168:Palmitates; D012756:Sheep; D012757:Sheep Diseases / Q000469:parasitology / Q000503:physiopathology*; D012965:Sodium Chloride; D014885:Waxes
chemical_list: D004338:Drug Combinations; D010168:Palmitates; D014885:Waxes; D012965:Sodium Chloride; C055480:bone wax