Gender effects in hearing loss in Dalmatians.

Brainstem auditory-evoked-response data were collected from 3101 Dalmatian dogs from 1984 to 1998 at the Veterinary Medicine Teaching Hospital at the University of California, Davis. Also collected were data on eye color and the presence or absence of a color-patch at birth. Our objective was to evaluate the role of gender in hearing loss, including the possibility that the probability of suffering unilateral or bilateral deafness was greater if the dam was hearing impaired than if the sire was hearing impaired. Results of a multiple-trait threshold-model analysis support the commonly held observation that females were more likely to be deaf than males. In addition, females were also more likely to have two blue eyes (a condition associated with an increased prevalence of deafness). However, gender differences in hearing loss were limited to these direct observations. There was no detectable difference in the prevalence of hearing loss between offspring of deaf mothers and the offspring of deaf fathers. Finally, there was no detectable decrease in the prevalence of hearing loss over the years covered in the data set - suggesting that Dalmatian breeders are not yet selecting against hearing problems.