If you think your purebred dog is just as healthy as your neighbor's half-breed, you're right, according to veterinarians. A five-year study completed by veterinarians at the University of California, Davis showed no difference between purebreds and mixed breeds when it comes to inherited health problems.
The Mixed-Breed Myth
Many people believe that blending breed types as is done in so-called designer dogs or mixed breeds makes for a healthier animal, because the prevalence of inherited health problems is reduced. The UC Davis study of veterinary cases showed that genetic disorders depend on the condition and not the dog. So a mixed-breed dog may be prone to the genetic conditions of all the breeds whose DNA he shares, depending on what they are. It's been believed that mixing breeds would eliminate the tendency to certain inherited disorders, but Dr. Jerold Bell, clinical associate professor at Tufts Cummings School of Veterinary Medicine and author of Veterinary Medical Guide to Dog and Cat Breeds, said this is not the case.
Purebred dogs inherit the traits and health of a specific, documented gene pool. Purebred breeders choose their puppy parents for specific attributes -- good temperament, solid health pedigrees and established lineage. A purebred breeder can trace your dog's ancestors and their health history back many generations. Health issues in specific breeds are more easily identified, so a breeder with a pedigree line susceptible to an issue such as elbow dysplasia will choose breeding stock without the disorder to eliminate it in future litters.
UC Davis researchers examined the veterinary records of more than 90,000 dogs between 1995 and 2010. All types of breeds were included, from purebreds to designer dogs to mutts. Researchers found that 13 of 24 genetic disorders occur at the same rate in mixed breeds as they do in purebreds. Health issues included cancers, heart disease, orthopedic problems, eye issues, allergies, bloat, liver disease and epilepsy. Of the dogs studied, 27,254 had at least one of the 24 genetic disorders. Ten conditions were found more frequently in purebred dogs, and one more frequently in mixed breeds.
Researchers found that the genetics involved in some disorders such as those which cause hip dysplasia, tumor-causing cancers and cardiomyopathy, are so prevalent throughout dog populations that both mixed breeds and purebreds are equally at risk. Some of this may be due to crossbreeding dogs who carry the gene for one or more health issues.
Identify your mixed-breed dog's ancestors with one of the DNA tests available that show the breeds in his lineage. This information can help pinpoint any breed-related predisposition your dog has to genetic conditions. The most accurate DNA tests are those that include many breeds. If your dog has a purebred ancestor as close as a grandparent, the tests are highly accurate.