Mitral valve disease is virtually universal in ageing Cavalier King Charles Spaniels, representing one of the most significant breed-specific welfare problems in companion dogs.
Mitral valve disease causes progressive welfare compromise: early disease is silent but as regurgitation increases, the heart enlarges and the lungs begin to fill with fluid during congestive heart failure episodes. Breathlessness, reduced exercise tolerance, and coughing from pulmonary oedema are clearly distressing. The distress of acute heart failure — struggling for breath — is severe and represents a welfare emergency. The predictability of this condition in Cavaliers makes it a preventable welfare crisis at the breed level: genetic selection using the breeding scheme can reduce disease prevalence, while screening allows early medical intervention. The welfare case for breeding only cardiac-cleared Cavaliers is compelling and supported by the breed health initiatives.