King Charles Cocker Spaniel puppy
It pains me to say this about such a lovely and sweet-natured breed, but the fact remains that this breed is in serious, serious trouble.
With Cavaliers, it all starts with heart disease – specifically, mitral valve disease, the #1 killer of this breed. Up to HALF of all Cavaliers will develop MVD by 5 years of age, and virtually ALL (99%) will have it by 10 years of age.
MVD is a true epidemic in the breed. Responsible Cavalier breeders must wait until age 3 or 4 before they will allow a Cavalier to breed, hoping that these older dogs who haven't yet developed MVD might be contributing genes that are more resistant to it. In addition, responsible breeders will only breed Cavaliers whose own parents made it to at least 5 years old without developing MVD. Finally, they're maintaining registries of the longest-lived Cavaliers in the hopes of incorporating these lines into their pedigrees.
No one should acquire a Cavalier King Charles Spaniel today unless they're prepared to spend lots of money for heart care and to very likely lose their dog in middle age.
As if heart disease wasn't enough, epilepsy is also a serious problem in Cavaliers.
And the newest disease to strike this hard-luck breed is syringomyelia (seer-IN-go-my-ELL-ya), where a Cavalier puppy is born without enough room in his skull to accommodate his brain.This lack of space causes the brain stem to become kinked and the back of the brain to be forced out of the skull and into the opening to the vertebral canal. This, in turn, forces cerebrospinal fluid into the spinal cord itself, and this kind of pressure hollows out a cavity in the spinal cord, hence the name syringomyelia, which translates to "flute spinal cord" (i.e. the affected spinal cord is hollow like a flute).
Some Cavaliers are only mildly affected, while others are severely so. Symptoms typically appear between 6 months and 3 years old, though syringomyelia has been diagnosed in Cavaliers up to 10 years old.
The most common symptom is an odd one – the dog scratches at his shoulder when excited or walking on a leash. This scratching is presumed to be due to abnormal skin sensations, because humans with syringomyelia have described the sensation as "creepy crawling" or "burning pain." Affected dogs may also be sensitive around their head, neck, and front legs, and may suddenly yelp for no apparent reason. Pain may be related to head posture – some affected dogs begin sleeping or eating with their head held up.
The most severe cases have spinal cord damage and are significantly disabled by 12 months of age, with a twisted neck, wobbly hindquarters, and/or weakness in their front legs.