Most people have heard that Mixed Breed or Designer Breed dogs are heathier than purebred dogs. It is said they are more genetically resistant to defects due to their greater genetic diversity, and there is truth in that. Purebred dogs can also suffer from generations of inbreeding to keep certain traits in the lineage, which can lead to diseases or defects cropping up more often as the genes for those aren't diluted in the gene pool by outbreeding. However, many Purebred dogs live long and healthy lives, so are Designer Breed dogs heathier than their Purebred counterparts?
A study conducted by the American Veterinary Medical Association tested Mixed Breed and Purebred dogs for susceptibility for twenty-four genetic disorders, and found "42% of genetic conditions was higher in purebred dogs... 4% of inherited disorders was higher in mixed dogs... and 52% of genetic conditions showed no difference in comparison." This study found strong evidence that Purebred dogs are more than 10 times more susceptible to genetic disorders that Designer Breed dogs. These problems are exacerbated in Purebred dogs when inbreeding becomes more common and genetic disorders become more prevalent.
Even though Purebred dogs are genetically more susceptible to disorders, there are other factors to keeping your dog healthy. Diet, exercise, and comfort all contribute to a dog's wellbeing.