To elucidate the inheritance of deafness in Dalmatian dogs, 825 dogs i
n 111 litters were evaluated for abnormalities in hearing through the
brainstem auditory evoked response (BAER). Recorded along with their q
uality of hearing (normal, unilaterally deaf, or bilaterally deaf) wer
e the sex, coat color, eye color and the presence or absence of a colo
r patch. The analysis considered deafness an ordered categorical trait
in a threshold model. The underlying, unobservable continuous variate
of the threshold model was assumed to be a Linear function of sex of
dog, coat color (black or liver and white), color patch (presence or a
bsence), eye color, the deafness phenotype of the parents and a random
family effect. Twenty-six percent of dogs were deaf in at least one e
ar. Eye color, color patch, sex and the hearing status of the parents
were all significant contributions to deafness. The heritability of de
afness, on the continuous unobservable scale, was 0.21. This value was
computed after correction for eye color, color patch, parental hearin
g status and sex, implying that significant genetic variation exists b
eyond the contribution of several single loci.