If you're owned by a border collie, you already know that they're a smart breed of dog. If your dog gradually becomes less obedient, or isn't picking up cues as fast as usual, deafness is a possibility. Loss of hearing is common in border collies, but intelligent canines compensate.
Prevalence
According to the Border Collie Club of Great Britain, approximately 3.6 percent of border collies experience bilateral or unilateral deafness. That's compared to 0.025 percent in the overall canine population. Bilateral means that the dog is deaf in both ears, while unilateral means one ear is affected. While a dog owner can usually tell if his dog is bilaterally deaf, unilateral deafness isn't so obvious. To make a diagnosis, your dog must undergo testing. Perhaps the most common canine hearing test is the Brainstem Auditory Evoked Response (BAER).
BAER Test
BAER testing consists of testing each ear individually, with the entire process taking no more than about 15 minutes. The test should be conducted by a board-certified veterinary neurologist or a veterinarian very well-schooled in the procedure. Sedation is generally not necessary, but is an option. Small earphones connected to a computer are placed in the animal's ears. The computer produces a stimulus click and records the response.
Middle-Aged Onset
The most common hearing loss in border collies doesn't emerge at birth, or when dogs are quite aged. Instead, onset of bilateral or unilateral hearing loss occurs in the dog's middle age, starting when he's about 4 years old. Working border collies, those who herd on a farm or ranch or for competition, require a good sense of hearing to respond to commands. An owner working closely with his dog probably notes something is amiss. However, non-working border collies are just as smart if not quite as busy, so as their hearing ebbs they might begin responding more to visual or other cues. According to the Pastoral Breeds Health Foundation, it's not uncommon for border collie owners whose dogs undergo BAER testing not to realize the dog is deaf until after the results are in.
Deafness and Color
Between 1994 and 2002, 2,597 border collies in Great Britain underwent BAER testing. The Centre for Small Animal Studies (CSAS) went through the data, working on the hypothesis that deafness in the breed is associated with merle gene. Merle is not a common color pattern in the breed. The United States Border Collie Association defines it as "a dilution of overall body color--black or red--with streaks or splotches of darker color," occurring on the colored areas of the dog's body, not the white markings. The study found that deaf border collies had higher rates of merle coats, as well as blue eyes and more white head markings than border collies with normal hearing.
Maternal Deafness
It's probably not surprising that the offspring of deaf dogs are far more likely to suffer hearing loss. No matter the color, odds of deafness increased by a factor of 14 for dogs whose mothers are deaf, according to the CSAS study. It concluded that deafness in the breed had a strong hereditary component, recommending that breeders should test for hearing and not breed affected dogs.
