A threshold model analysis of deafness in Dalmatians

Area of Science:

• Veterinary Genetics
• Animal Audiology
• Canine Health

Background:

• Deafness is a significant concern in Dalmatian dogs, impacting their quality of life.
• Understanding the genetic basis of deafness is crucial for effective breeding and management strategies.

Purpose of the Study:

• To investigate the inheritance patterns of deafness in a large cohort of Dalmatian dogs.
• To identify specific factors contributing to the prevalence of hearing abnormalities in the breed.

Main Methods:

• Brainstem Auditory Evoked Response (BAER) testing was used to assess hearing in 825 Dalmatians across 111 litters.
• Deafness was analyzed as an ordered categorical trait within a threshold model, incorporating various phenotypic factors.
• Statistical analysis examined the influence of sex, coat color, eye color, color patch presence, and parental hearing status on deafness.

Main Results:

• Twenty-six percent of the evaluated Dalmatians exhibited deafness in at least one ear.
• Eye color, presence of a color patch, sex, and the hearing status of parents were identified as significant factors contributing to deafness.
• The estimated heritability of deafness was 0.21, even after accounting for known influencing factors.

Conclusions:

• Deafness in Dalmatians has a significant heritable component, influenced by multiple genetic and phenotypic factors.
• The findings suggest complex inheritance patterns for deafness, potentially involving genes beyond those associated with coat or eye color.
• This research provides valuable insights for selective breeding programs aimed at reducing deafness prevalence in Dalmatian dogs.