What is it and why do we do it?
BAER testing is brainstem auditory evoked response testing. The response is collected with a special computer through extremely small electrodes placed under the skin of the scalp: one in front of each ear, one at the top of the head, and one between the shoulders. It is rare for a dog to show any evidence of pain from the placement of the electrodes - if anything the dog objects to the gentle restraint and the irritation of wires hanging in front of its face. The stimulus click produced by the computer is directed into the ear with a foam insert earphone. Each ear is tested individually, and the test usually is complete in 10-15 minutes. Sedation or anesthesia are usually not necessary unless the dog becomes extremely agitated, which can usually be avoided with patient and gentle handling. A printout of the test results, showing the actual recorded waveform, is provided at the end of the procedure. Test results are confidential. https://www.lsu.edu/deafness/baerexpl.htm#:~:text=The%20hearing%20test%20known%20as,electrical%20activity%20of%20the%20heart.
Congenital hereditary sensorineural deafness (CHSD) is a common form of deafness in dogs and has been reported in over 80 breeds, including the Dalmatian, Bull Terrier, Border Collie and Australian Cattle Dog. While for many years, the mode of inheritance of CHSD has been uncertain in many breeds including the Australian Cattle Dog, results from a recent study support CHSD being inherited as an autosomal recessive trait. In other words, they are still unsure exactly what causes it and there is no pre-breeding test that a breeder can do to lower or eliminate the risk beforehand yet other than BAER test the parents which we do. It has been advised to only breed full hearing parents, which we do. If you would like to read more about the studies that have been done on ACD's pleaase see here: https://bmcvetres.biomedcentral.com/articles/10.1186/1746-6148-8-202
The dog is scored in three ways: Bilateral meaning normal hearing in both ears, unilateral meaning deaf in one ear and normal in the other, or bilateral deafness meaning deaf in both ears. Unilaterally deaf dogs are difficult to identify unless they are BAER tested because they compensate quite well and respond as like their normal hearing littermates. Every single breeder should be BAER testing their puppies before sending them to new homes.