Siblings should only be used after careful screening. One obstacle to controlling mitral valve disease is that clinical signs associated with the disorder are generally not evident until after a dog has reached breeding age. However a heart murmur can often be detected long before the onset of clinical signs. In the United Kingdom and in Sweden, the cavalier King Charles spaniel clubs have instituted certification programmes whereby dogs are examined annually for a cardiac murmur by veterinarians. Breeders are encouraged to select mature rather than young dogs for breeding, that have been certified free of murmurs.
Swedish law prohibits the use for breeding of dogs with any congenital heart disease.
Resources Patterson, D.F. 1996. The genetics of canine congenital heart disease. This reference has good information for breeders and veterinarians regarding screening and genetic counselling for congenital heart defects. Copyright 1998 Canine Inherited Disorders Database. All rights reserved.