This is a very controversial subject and people do feel very strongly about their position. On one hand, there have always been those that believed that mutts were healthier dogs. On the other hand, purebred purest take opposition to that but the example above proves at least an element of truth to this theory. To me, there seems to be conflicting evidence but after much research I think I understand why.
Common Sense Example: A Shih Tzu or Pug has a very flat face, thus they are at risk for breathing difficulties and nasal problems. If you cross a Poodle, for example, with a Shih Tzu, the nose is pulled out just enough to prevent nasal problem from the Shih Tzu. But say you crossed a Shih Tzu with a Pug (I saw one once. CUUUTE!), you still have that flat face and potential problem with nasal problems and breathing. That is a structural example but could very well parallel some genetic issues as well.
Over the years, purest in the purebred breeding history have tried desperately to bred that perfect specimen within each select breed. Continual inbreeding has brought with it a special set of genetic problems. To this end all would agree. The key to hybrid vigor is selecting breeds from two different lines that have different defects. A proper understand of genetics would then have to lead one to admit that the pup has a chance for a healthier life. So where is the conflicting information?
I will refer to a well known study, published in the Journal of the American Veterinary Medical Association, based on data obtained from 90,000 purebred and mixed-breed dogs between 1995 and 2010. All dogs in the study were examined at UC Davis' veterinary medical teaching hospital.
In the study group, over 27,200 dogs were diagnosed with various genetic disorders such as cataract, cancers, heart diseases, liver conditions, and orthopedic problems. Researchers choose 24 genetic disorders that were diagnosed were severe enough for the dog owners to consult a veterinarian early in the early stages. The specific diseases were chosen because they were easily identified and diagnosed. The study showed that the prevalence of at least 13 of the 24 disorders was roughly the same for both pure-bred and mixed-breed dogs. One disorder was more prevalent in the mixed-breeds. Ten diseases were common in purebred dogs. So what do they mean to claim that mixed breeds are not healthier?
The study also found that dogs who share a common lineage have higher chances of developing particular genetic disorders. Still, interpreters of this study say that mixed-bred dogs are not healthier.
Animal physiologist Anita Oberbauer concluded that, “Overall, the study showed that the prevalence of these genetic disorders among purebred and mixed-breed dogs depends on the specific condition...” She cited several conditions that were more prevalent in purebreds than in the mixes. So how can they claim a mix is no healthier?
It is a matter of as understanding and interpreting all the facts. As in my previous example and the conclusions of the study, it is obvious that the mixes do not have some of the issues as the purebreds. However, there are plenty of mix bred dogs with health issues. It depends on WHAT issues we are talking about.
It is true that the chances of a pup getting a breed-related disorder are cut in half by mixing the breeds, so long as they don’t have the same genetic risk factors. However, with the common genetic diseases that are seen across all breeds, there is going to be the same frequency. You won’t get a designer dog that will ward off worms, parasites, or viruses better than a purebred dog. Your dog can’t be fed junk food and get obese and be expected to not be diabetic. Age related diseases, like heart failure, arthritis, hip dysplasia, canine senility, and tooth decay are not going to be avoided in a mixed bred dog. In this sense, Mix breeds are not healthier – and THAT is what they are saying.
However, I will tell you this from our experience. Our Labradoodles and Goldendoodles have larger litters with less infant mortality that do our pure-bred moms. For that reason alone, I content that the verdict is not total in on this one.
Further, some of the opinion also comes from the perspective that Veterinarians will say that they see all breeds, designer mixes, and mutts in the clinic. Well yes, the people that will go most frequently to the clinic are the one with sick dogs. That still doesn’t negate the above mentioned examples of hybrid vigor.
Farmers have worked on achieving hybrid vigor for years. Robert Wells, of The Samuel Roberts Noble Foundation wrote, “Hybrid vigor is most fully expressed when you use bulls and cows of known ancestry - not just breeding any bull to a cow you pick up from Joe down the road or you bought at the sale barn because the price was right.” There is a method to the madness. Wells concluded, “It does not matter if you are selling your calves at weaning, as yearlings or retaining ownership through the feedlot; you cannot afford to give up the advantages that hybrid vigor will convey to your bottom line.”
The bottom line is that no matter if the pup comes from purebred parents or mix breed parents, they need to start with parents that are healthy and free of genetic potential for problems- as far as we can know. Just because you get a designer pup, indeed, does not insure a healthy pup. It is the difference between purposely-bred and random-bred dogs, no matter what breed or breed mix.
- US Davis Science New and Information,http://news.ucdavis.edu/search/news_detail.lasso?id=10613
- Anita Oberbauer, Animal Science, (530) 752-1252,firstname.lastname@example.org
- Pat Bailey, UC Davis News Service, (530) 752-9843,email@example.com
- National Animal Interest Alliance,http://www.naiaonline.org/articles/article/the-clinical-truths-about-pure-breeds-mixed-breeds-and-designer-breeds
- Robert Wells, Samuel Robert Noble Foundation, Heterosis… Hype or Legit? © 1997-2014http://www.noble.org/Ag/Livestock/Heterosis/