Deafness is commonly found in dalmatians, but it's not a normal trait for the breed since deafness is caused by a genetic abnormality. A growing population of deaf dalmatians is a result of irresponsible breeding -- allowing deafness-gene-carrying specimens to continues to breed, passing the genetic abnormality from generation to generation. Deaf dalmatians are prone to behavior problems including aggression.
Dalmatian deafness is a genetic abnormality associated with the extreme piabald gene. Dalmatians with blue eyes are most likely to carry the genetic abnormality, but the exact mechanism of why deafness occurs is unknown. The hearing loss can effect both ears or one. Melanocyte cells, which are responsible for pigmentation and inner ear function, are affected by this genetic problem. There are no tests to detect the carrier of the extreme piebald gene and even dalmatian parents with full hearing can produce deaf puppies.
The test to determine dalmatian deafness is the brainstem auditory evoked response test, or BAER. The puppies are usually born with normal ear function although hearing does not start until 14 to 16 days after birth. A dalmatian puppy can fully hear at 5 weeks old, which is when the BAER is administered. During the BAER test, a noise is delivered to each ear and the brain's response is detected through electrical sensors on the puppy's head. Eight percent of the dalmatian population are bilaterally deaf and 22 percent are unilaterally deaf.
Dalmatian deafness results in significant behavior problems for the breed. The Dalmatian Club of America takes a firm stand on having bilaterally deaf dalmatian puppies euthanized by a veterinarian. A bilaterally deaf dalmatian is hard to train, is accident prone, and has a tendency to develop anxiety and aggression. It's easy to startle a deaf dog, which can lead to snappish behaviors. It's especially important not to bring a bilaterally deaf dalmatian into a house with small children. A bilaterally deaf dalmatian can be friendly and nonaggressive, but anectodal evidence of aggression among deaf dalmatians is abundant, and it's impossible to tell which puppies will develop aggressive tendencies. Unilateral deaf dalmatians can lead perfectly normal lives and can be trained as easily as a dalmatian with full hearing.
The best way to prevent purchasing a deaf dalmatian is to avoid purchasing this breed from pet stores or inexperienced breeders. Contact the Dalmatian Club of America or a reputable breeder with years of experience for assistance when purchasing a dalmatian. If a puppy has not been BAER tested, do not purchase the puppy no matter how cute he looks. If a puppy has unilateral deafness, spay or neuter the puppy to prevent future breeding since a unilateral deaf dalmatian still has the genetic abnormality. Do not breed dalmatians who have produced deaf puppies, and be cautious if the dalmatian parents have blue eyes.