The Shetland sheepdog, nicknamed the Sheltie, is often called the miniature collie, because that's what he looks like. While most Shelties aren't particularly prone to deafness or hearing loss, that's not true of those with blue merle coloring. It's a lovely shade, but involves genetic problems.
A blue merle isn't aqua or navy, and puppies aren't baby blue. It's really a silver shade, with mottled coloring. The American Shetland Sheepdog Association's standard for the blue merle explains that merling is a dilution gene acting on the dog's basic black coat, causing it to appear silver or gray with areas of black. These dogs have white and tan on their faces and legs. Some blue merles might have more black than blue on the bodies, a color known as "cryptic blue."
Breeding two Shelties known to have the merle gene often ends up badly. Many of these puppies are deaf, with some also blind. Although not all puppies born as "double merles" are deaf, breeding two merles is a dicey proposition. Some puppies with this gene combination die shortly after birth. A double merle with blue eyes is more likely to be deaf than a brown-eyed dog. Some dogs are only partly deaf, able to hear out of one ear. Perhaps fortunately, dogs with the double merle gene are usually sterile, so they can't pass on their hereditary defects.
The blue merle gene affects not only Shelties but other canine breeds. According to Louisiana State University, both the blue merle and piebald gene makes dogs prone to deafness. Blue merle is found in collies, a close cousin of the Sheltie, and also in Harlequin Great Danes, Old English sheepdogs, American foxhounds, dappled dachshunds, among others. Deafness develops in puppyhood before the ear canal opens. Dr. George M. Strain at LSU states that the blood supply to the shell-like cochlea in the inner ear degenerates, causing the death of the cochlea's nerve cells. That means there's no window when an affected blue merle Sheltie can hear.
Choosing A Puppy
If you plan to bring home a blue merle Sheltie puppy, make sure he can hear before you buy him. Ask the breeder about his genetic background to ensure the puppy's not a double merle. The breeder also should let you see the puppy's parents. Testing the puppy's hearing shouldn't be difficult. Call him, clap your hands, make noises and see if he responds.
If you have a deaf Sheltie, that doesn't mean he can't be trained. In fact, training is even more important than for a hearing canine, as he's vulnerable to dangers that hearing dogs can avoid. Find a dog trainer who knows how to teach deaf dogs via hand signals. Because calling your dog won't work, you can also teach him to respond to flashlights and similar visual cues. Your deaf dog has special needs, and that includes someone to love him.
- Vetstreet: Shetland Sheepdog
- PetMD: Shetland Sheepdog
- Orthopedic Foundation for Animals: Genetics and Inheritance of Canine Deafness
- American Shetland Sheepdog Association: Blue Merle
- Central Illinois Sheltie Rescue: Sheltie Colors
- Pet MD: Training and Caring for a Deaf Dog
- Vetstreet: Strategies for Training a Deaf or Blind Dog
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