Congenital deafness in Dalmatian dogs: The effect of the NCDH breeding program

Hereditary deafness in Dalmatian dogs has been a problem for many years, and has been studied for years too. Nowadays, the hereditary deafness in Dalmatians is known to be a form of Canine Congenital Sensorineural Deafness (CCSD). Several phenotypical factors seem to be involved in the development of this disease. A breeding program for Dalmatian dogs has been set up in several countries, to help prevent deafness. In the Netherlands, the breeding program was set up by the Dutch Club for Dalmatian Dogs (NCDH). However, the effectiveness of the breeding program by NCDH on the incidence of CCSD is unclear and subject of this research.
A Logistic regression analysis has been performed on data collected by the NCDH from 1995 to 2018: 4948 BAER-tested Dutch pups have been analysed on the degree of association between hearing status and birth year period, head spot, coat colour, blue eyes, litter size and data of the parents. The effects of the sire and dam were considered as random effects.
The incidence of deafness has decreased since the breeding program was implemented. The incidence of deafness was proven to be significant decreasing for the birth periods 2001-2006 and 2013-2018. The decrease was also found for unilateral and bilateral deafness separately. It was also found that females have significantly higher odds on deafness than males. Furthermore, presence of head spot significantly decreases the odds on deafness, whereas blue eyes do not seem to have a significant effect.
The incidence of deafness might have decreased more, had dogs with presence of a head spot been allowed for breeding.