Dog Myxomatous Mitral Valve Disease: Breeding Reform

The high prevalence of myxomatous mitral valve disease in cavalier King Charles spaniels reflects breeding practices that have prioritised appearance over health, and reform is urgently needed.

Key Facts

MMVD is so prevalent in cavaliers that it has been described as a breed-wide welfare crisis
Studies show cavaliers bred from parents with murmurs develop disease significantly earlier
The Cavalier King Charles Spaniel Club has implemented a Mitral Valve Disease Breeding Protocol since 2012
Under the protocol, dogs must be over five years and free of murmurs before being used for breeding
Adherence to the protocol has been inconsistent, and disease prevalence remains high in unscreened lines

Welfare Considerations

The MMVD crisis in cavaliers represents one of the clearest examples of how breed standards and breeding practices can cause widespread suffering. Dogs from unscreened lines often develop heart disease by age 2-3, requiring medication for years. The cost of cardiac medication can be prohibitive, meaning some affected dogs go untreated. Breeding from health-tested parents significantly reduces the risk of early-onset disease. Kennel clubs, breeders, and buyers all have roles to play in shifting incentives toward health-first breeding.

What You Can Do

Only acquire cavaliers from breeders who adhere to the MVD Breeding Protocol
Insist on seeing parental cardiac screening certificates before purchasing a cavalier puppy
Support kennel club health testing requirements for breeds with known hereditary disease burdens
Advocate for mandatory health testing before registration of puppies in high-risk breeds