Deafness in Australian Cattle dogs
The way deafness is inherited in Australians Cattle dog is unknown and could affect as much as 3 percent of the breed. For that reason I feel it is important that Brainstem Auditory Evoked Response testing be done. Breeding two "BAER" tested dogs does NOT guarantee all offspring will have normal hearing. However, it does inform you as to whether or not the dog being tested has normal hearing in both ears, uni-lateral hearing where the dog is deaf in one ear but has normal hearing in the other, or is completely bi-laterally deaf with no response to sound in either ear.
Studies are limited, so it is unknown if deafness in Australian Cattle dogs is a dominant or recessive trait, as it is possible for normal hearing parents to produce deaf offspring. It is unknown, but may be possible, that two deaf dogs could produce both uni-lateral deaf and normal hearing puppies. This phenomenon has occurred in Dalmatians. It is also possible, that deafness in Australian Cattle dogs is linked to the piebald gene. This gene is what causes Australian Cattle dogs to be born solid white, except for occasional solid colored body or head spots.
In piebald and "white" related deafness puppies are born with normal cochlea, the part of the inner ear that picks up sound. Then in the first few weeks after birth part of the blood supply to the cochlea is lost. The cells die resulting in permanent deafness. The exact cause of the loss of blood to the cochlea is unknown but, is believed to be linked to the absence of pigment producing cells in the blood vessels.
Studies have shown that pigment cells play a critical roll in the development of the inner ear. For this reason, I feel that it is important to select breeding stock that have strong dark pigmentation and express at least some body spots i.e. head spots and tail spots. Furthermore, I think breeders should breed against plain faced dogs or completely "body spot" free dogs as this is breeding against pigment and therefore possibly breeding for deafness.
Studies are limited, so it is unknown if deafness in Australian Cattle dogs is a dominant or recessive trait, as it is possible for normal hearing parents to produce deaf offspring. It is unknown, but may be possible, that two deaf dogs could produce both uni-lateral deaf and normal hearing puppies. This phenomenon has occurred in Dalmatians. It is also possible, that deafness in Australian Cattle dogs is linked to the piebald gene. This gene is what causes Australian Cattle dogs to be born solid white, except for occasional solid colored body or head spots.
In piebald and "white" related deafness puppies are born with normal cochlea, the part of the inner ear that picks up sound. Then in the first few weeks after birth part of the blood supply to the cochlea is lost. The cells die resulting in permanent deafness. The exact cause of the loss of blood to the cochlea is unknown but, is believed to be linked to the absence of pigment producing cells in the blood vessels.
Studies have shown that pigment cells play a critical roll in the development of the inner ear. For this reason, I feel that it is important to select breeding stock that have strong dark pigmentation and express at least some body spots i.e. head spots and tail spots. Furthermore, I think breeders should breed against plain faced dogs or completely "body spot" free dogs as this is breeding against pigment and therefore possibly breeding for deafness.
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