(Photo property of Mr. & Mrs. Christman)
Dogo's, like any primarily white dog, can be born partially or completely deaf. For this reason it is of utmost importance that ALL Dogos be BAER tested.

What IS BAER testing?

The BAER (Brain Auditory Evoked Response) test is a safe and painless test to determine if a dog has a hearing loss.  A BAER test is performed by inserting an earphone into the ear canal, while recording needle electrodes are inserted in the skin to record brain wave response.  Each ear is tested individually.  A series of  clicks are transmitted via the earphone to stimulate a response.  The response is detected by the needle electrodes, transmitted to the BAER device, where it is recorded. (on a monitor screen or on paper or both)  The click series generally starts at about 70 decibels and is gradually increased to 100 decibels (if hearing is not detected at the lower levels).

By recording the response signals from the needle electrodes, the BAER device can then produce a graphic display of the dog's hearing responses.  A near flat, low wavy line depicts no response, therefore, no hearing.  A wavy line of several sharp peaks and deep valley depicts responses and hearing sense in that ear.

A dog that is labeled unilateral, has hearing in only one ear. Bilateral normal has hearing in both ears. Bilateral abnormal has no hearing in either ear, and the dog is considered completely deaf.

Examples of what BAER testing looks like:

(Photos property of Mr. & Mrs. Christman)
The puppy on the Left shows "Normal hearing," note the existance of the tall sharp spikes. The pup on the Right, shows "Unilaterally Deaf Hearing," Note the tall sharp spikes on one of the read outs and the low wavy line on the other read out.

Statisitics on breeding with the deafness factor:

More information resources on Deafness in Dogs:

• "Deafness prevalence and pigmentation and gender associations in dog breeds at risk," The Veterinary Journal 167(1):23-32, 2004 (PDF format). © 2003 Elsevier Science Ltd.
• "Hereditary deafness in dogs and cats: Causes, prevalence, and current research," Tufts' Canine and Feline Breeding and Genetics Conference, Old Sturbridge, MA. October, 2003. Conference PowerPoint presentation.
• "Congenital deafness and its recognition," Veterinary Clinics of North America - Small Animal Practice 29:895-907, 1999. © 1999 W.B. Saunders.
• Deafness data analysis from: Strain, G.M. and B.L. Tedford. 1996. Deafness prevalence and associated phenotypic markers in dog breeds with high risk. Proc. 14th Ann. Vet. Med. Forum, ACVIM 14:772. San Antonio, May, 1996.