As a whole, cavaliers are hardy, healthy little spaniels, but as with all purebred dogs, they are not without health issues. Part of that is the result of the small gene pool created in 1926, when breeders of the flat-nosed King Charles Spaniel (now called English Toy Spaniels) were offered a prize to bring back the longer muzzle portrayed in the pictures of King Charles II. At that time, six foundation dogs became the groundwork from which all purebred Cavalier can be traced today.
Reputable breeders will have a good knowledge of pedigree, and will attempt to breed from stock that a free of major health defects. Still, recessive genes can crop up when least expected.
Debilitating eye problems are not common, however most breeders have testing done by board-certified veterinary ophthalmologist to screen for the possibility of hereditary eye disease, such as retinal dysplasia, detachment and cataracts.
Many toy breeds have a condition called luxating patellas. Because their bones are small, the anatomy of a toy dog occasionally allows the kneed cap to slip out of its groove. While luxating patellas do not often hinder toy dogs, a surgical correction is available if the problem exists.
Hip dysplasia has been known to occur in a small percentage of Cavaliers. This condition involved a hip socket that's too shallow for the head of the leg bone. Again, toy breeds are usually troubled by dysplasia, but in severe cases, bone deformity can cause arthritis and pain.
Mitral Valve Disease (MVD) and Syringomyelia (SM) are far more challenging problems to the breed and breeders. Both conditions can show up later in life and there is no test to predict if or when a dog will encounter onset. The actual mode of inheritance, genetic and environmental factors that influence these conditions are still unknown. Both are thought to be complex poly-genetic combinations that rely on a threshold level from one or both parents. All Cavaliers are carriers of both conditions, irregardless of blood lines. Although major progress on improving hearts has been made over the past two decades (through testing of breeding stock), syringomyelia has only recently been discovered and for now, there are more questions than answers. Unless and until the gene marker(s) for these diseases are identified, toy dogs will continue to be affected and breeders will be challenged to manage their stock based on pedigree knowledge and symptoms. Any breeder sayig they do not have these problems in their bloodlines are either uneducated or not telling the truth.
Although common in most toy dogs, Mitral Valve Disease (leaking heart valve) seems to present at an earlier age in the Cavalier. Cardiologist statistics worldwide indicate that about 50% of Cavaliers will develop at least a mild heart murmur by age 5, 70% by age 7 and over 98% by the age of 10. Cavaliers can lead perfectly normal lives for years after developing a murmur, many never slowing down a bit from the disease. If affected with symptoms (coughing), it is usually very late in life and can be treated with medication.
Syringomyelia is thought to be similar to Arnold-Chairi malformation in humans. Based on current theory, it's believed the bottom half of the skull develops in a way that crowds the cerebellum of the brain, impeding the path of cerebrospinal fluid movement around the brain and spinal cord. The increased pressure and pooling of cerebrospinal fluid may cause irritation and damage to the spinal cord, resulting in symptoms of neck scratching, headache and in extreme case, paralysis. Dogs suffering debilitating symptoms of SM are rare.
For more information on Cavalier health issues, we recommend this comprehensive website www.aboutcavalierhealth.com