I am looking for a Cavalier King Charles Spaniel puppy to purchase and several breeders have warned me about the heart disorder in Cavaliers. What should I look for when interviewing with breeders?
Make sure that both parents of the puppy you are considering to purchase have been heart cleared within the past 12 months by a cardiologist preferrably. Also try to obtain information about the heart clearances on ancestries for each parent. Heart murmurs are believed to be inherited through a polygenic mode of inheritance. All dogs have heart disease in their genetic history, however the Cavalier often shows signs earlier than most other breeds and therefore the studies in Cavaliers have been more extensive than other breeds. Polygenic genes are believed to need a specific number of markers passed on for the disorder to appear. One parent cannot give enough markers to cause the disorder and it takes two parents to pass on markers that add up to the certain number needed to cause the disorder to appear. Most Cavaliers probably carry markers, but at this time a specific marker or DNA profile has not been established. If you are getting a puppy from a breeder who has several generations of heart certifications then you will have more information to go on, but polygenic genes can skip many generations before they appear again, so Cavalier breeders cannot guarantee you that a puppy will not develop a heart problem. Most breeders will do the very best they can to breed away from heart issues and will give you some type of health guarantee to help you get a replacement puppy, while keeping the affected puppy, should the unexpected happen. Polygenic genes are also affected by diet and environment, so these two areas become the new owner's responsibility. If a Cavalier is raised in a home with a smoker then the second-hand smoke could be the tipping point to cause the heart disorder to appear. If the new owner is feeding a grocery store type dog food then diet can play a huge role in causing the heart disorder to appear. You will need to really discuss the best options with your breeder about the genetic background along with recommended diet and environment to give your puppy the best opportunity to live a long and healthy life.