Clear-to-Carrier
Breedings Produce

50% Carriers
50% Clear

Clear-to-Affected
Breedings Produce

100% Carriers

Carrier-to-Carrier
Breedings Produce

50% Carriers
25% Clear
25% Affected

Carrier-to-Affected
Breedings Produce

50% Carriers
50% Affected

Affected-to-Affected
Breedings Produce

100% Affected

Currently the only means of detecting carriers is through "Test Matings" (breeding to a known carrier or affected Cavalier) or unintentionally, by breeding a pair and that breeding resulting in producing affected offspring. Make sure when you buy a puppy you are buying from a breeder who is involved in genetic testing of their breeding stock. Health certifications only tell you if a dog is affected or clear and carrier-to-carrier is where the affected can occur from two parents that test out perfectly clear on all health testing. If both parents test out clear on all their health certifications, but are both carriers for the same disorder they will produce an affected offspring. Breeders do not want to produce additional affected offspring or offspring that might be a carrier so it is very important for families to keep in touch with their breeder throughout their Cavalier's life time and let their breeder know of any disorders that might become known, even if the disorder is a late onset in life you should still contact your breeder because he/she will be able to put that in their notes and use the information during pedigree research before breeding.

The following from the book "Future Dog, Breeding For Genetic Soundness" by Patricia J. Wilkie is published by the Minnesota Agricultural Experiment Station in cooperation with the AKC Canine Health Foundation.

Every breeder is a keeper of the "genetic flame" for his or her breed. Every breeding decision an individual breeder makes has the potential to affect the future of the breed. For conscientious breeders, each attempt to produce quality purebred dogs includes a strong commitment to reduce inherited disease.

These disorders often go undetected until the condition becomes frequent enough to be recognized as inherited. Generations may be unaffected when carriers are rare. As unaffected carriers become common, more affected individuals will appear. Removing affected individuals from the breeding population is not an effective solution since many unidentified carriers remain. The disease-producing genes will continue to spread unless unaffected carriers can be identified and selective breeding practiced.

"Control of Canine Genetic Diseases" by George A. Padgett, DVM is a book I highly recommend to anyone who is considering breeding dogs of any breed. Dr. Padgett provides a vast amount of information and this book is written so a breeder (with or without a BA Degree) can follow and understand and learn how to better predict how disorders might occur before they happen. All breeders must learn how to manage genetic diseases within their chosen breed. Breeders must keep records on all puppies produced and have feedback from the families that purchase their puppies for the lifetime of each puppy ever produced. As a breeder I want to stay in touch with every family and know everything health related about the offspring I produce. If you are looking for a breeder make sure you find a breeder who has a history and knowledge of previous puppies produced because you want to work with a breeder who is following the genetics of the lines they are producing or adding to.