The skull shape of toy dog breeds, such as chihuahuas and Cavalier King Charles Spaniels, is a significant risk factor for painful neurological conditions, reports a group of British and Canadian veterinarians.
Certain small dogs are predisposed to develop a condition called Chiari-like malformation, in which spinal fluid gets blocked where the skull connects to the spinal cord. This, in turn, can lead to syringomyelia, a painful formation of cysts form in a dog's spinal cord. There's some debate about the underlying cause of canine Chiari malformations -- but one significant factor, researchers write in the journal Canine Genetics and Epidemiology, is the shape of a pup's skull.
Thomas Mitchell, a veterinary student at the University of Bristol in England, and his colleagues analyzed the shapes of 133 Cavalier King Charles Spaniels' noggins, and compared these measurements to the incidence of syringomyelia. They found that dogs with shorter snouts, in relation to the broadness of their skulls, and heads with forward-facing domes were at an increased likelihood of developing the neurologic disorder.
"Our findings may allow breeders to select away from the condition over fewer generations by choosing appropriate matings and offspring to continue breeding programs," Mitchell says in a press release. "The identification of an appearance that might protect against developing the disease is a significant step forward in tackling this painful condition."
Even better would be for dog owners to shy away from purebred pups in favor of those rescued from shelters. That's not to knock ethical dog breeders -- or a preference for a particular breed -- but picking a rescue saves one out of millions of needy pooches. Opting for a shelter animal also ensures pet owners don't contribute to the demand for dogs with unhealthy traits bred into canine DNA.
All dogs -- purebred or not -- can develop unhealthy conditions, as canine experts Julie Hecht and Mia Cobb write for The Dodo. But the difference is in the disease's roots -- if purebred dogs continue to suffer due to too-round heads, for example, that's on us.