PMC4574391_01
Histogram showing the results of 216 Border Collies that were BAER tested at two herding trials. Groups shown had normal hearing (205), bilateral deafness (5), unilateral deafness (1) or reduced hearing (5), sorted to the closest half year of age.
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Fig1
One was deaf in one ear, five were bilaterally deaf, and five had reduced hearing (Figure  1).
Pedigrees of three families of Border Collies with multiple members that were deaf by BAER testing. Age of onset of hearing loss shown below the darkened symbol, when known.
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PMC4574391_01_40575_2014_6_Fig2_HTML.jpg
Fig2
Some dogs were BAER tested at more than one age, but most were tested only at the age indicated in Figure  2. An autosomal dominant pattern of inheritance appears to be the best fit (Figure  2). A similar mating of two deaf parents in Family 1 (Figure  2) suggests that not all pups will necessarily be deaf, excluding an autosomal recessive pattern of inheritance.