Are Mixed Breed Dogs Really More Healthy?

The assumption has long been held that the best way to avoid many inheritable diseases in dogs is to adopt a mixed breed dog, or a mutt. While many of the well known inheritable diseases have been linked to specific breeds of dogs, no study has ever set out to show the lack of these diseases in mixed breed dogs, until now.

A group of veterinary researchers from the University of California, Davis set out to investigate how frequently many of the commonly seen inheritable diseases would occur in mixed breed dogs as compared to pure bred dogs. In contrast to many veterinary studies with very small numbers of dogs, this study analyzed 27,254 dogs with 24 various diseases that are known to be inheritable. Some of the more common internal medicine diseases evaluated included Cushing’s disease, hypothyroidism, liver shunts, and Addison’s disease. Other well known conditions included many congenital heart defects, various types of cancer including lymphoma and mast cell tumor, and multiple orthopedic conditions including hip and elbow dysplasia, as well as cruciate ligament tear.

As was to be expected, 10 of the diseases were seen more commonly in pure bred dogs, including hypothyroidism, dilated cardiomyopathy, and cataracts. Somewhat surprisingly, however, 13 of the 24 diseases that were evaluated did not show any bias towards pure bred dogs compared to dog of mixed breeding. This means that there is no significant difference in risk of contracting one of these diseases for a mixed breed dog compared to a purebred. This group of diseases included Cushing’s disease, Addison’s disease, hip dysplasia, and multiple types of cancer. Cranial cruciate ligament rupture, a very common orthopedic condition, was actually seen significantly more often in mixed breed dogs.

Are Mixed Breed Dogs Really More Healthy?

Inherited diseases are, by definition, associated with some degree of genetic mutation. Since we know that all breeds of dogs originated from a common ancestral pool, and genetic diversification and breed selection / separation has only occurred in the more recent past, it stands to reason that diseases caused by genetic mutations long ago should not be found in any higher proportion in pure bred versus mixed breed dogs. Genetic mutations that have occurred much later in the diversification process, for example causing hypothyroidism, likely will affect a smaller subset of dogs making pure bred dogs more at risk. This may be better conceptualized using a family tree image. The common ancestors may be grouped together in the “trunk” of the tree, and any mutation occurring in this area is likely to affect all branches. A mutation that occurs on an isolated branch, or in the case of dogs after the selection process of specific breeds, is only likely to affect those specific breeds, and not the rest of the tree.

So how does this impact you when it is time to pick out a new companion? There are many positive attributes to bringing home both mixed breed dogs available at the local shelter and pure bred dogs from a reputable breeder. Deciding on what kind of dog to bring home should be a well thought out process, weighing all of the positives and negatives of the breed(s) involved. The conclusion of this study should in no way detract from adopting a mixed breed shelter dog; it should just be one more puzzle piece to help make the most informed decision.

Bellumori TP, Famula TR, Bannasch DL et al. Prevalence of inherited disorders among mixed-breed and purebred dogs: 27,254 cases (1995–2010). J Am Vet Med Assoc 2013; 242: 1549-1555.

By | Posted In In the News

Related Articles

MedVet Chicago becomes eighth Level I Veterinary Trauma Center

MedVet Chicago joins an elite group as the eighth hospital internationally to be certified by the American College of Veterinary Emergency and Critical Care (ACVECC) Board of Regents and Veterinary Committee on Trauma (VetCOT) as an official Level I Veterinary Trauma Center (VTC) and the only Level 1 VTC in Chicago. Hospitals receiving this unique distinction undergo an intensive application and verification process that requires the availability of board-certified specialists for consultation seven…

Read More

MedVet Expands Emergency Services to Mahoning Valley in Northeast Ohio

MedVet Medical & Cancer Centers for Pets is pleased to announce its expansion into Mahoning Valley in northeast Ohio with the addition of the After Hours Animal Emergency Clinic which is now called MedVet Mahoning Valley.  This partnership will provide local veterinarians continued support and access to emergency veterinary care in the greater Mahoning Valley community. “We are very excited to be expanding in the Mahoning Valley community,” said MedVet President, Dr. Eric…

Read More

Dogs Injured in Car Chase Through Neighborhood Receive Care at MedVet New Orleans

CBS News: Dogs injured during car chase through neighborhood face painful recovery. Read More…

Read More

MedVet Expands Emergency Veterinary Care to Dallas

Dallas, Texas: December 14th, 2016. MedVet Medical & Cancer Centers for Pets is pleased to announce its expansion into Texas with the addition of Emergency Animal Clinic, Inc. which includes three emergency veterinary hospitals in the greater Dallas area. As of today, each location will become part of the MedVet family of hospitals and renamed as follows: the Greenville location is now MedVet Dallas, the Richardson location is now MedVet Richardson, and the Uptown Dallas…

Read More

MedVet Medical & Cancer Centers for Pets Announces New Mobile Friendly Web Site

Columbus, Ohio: December 11th, 2016. MedVet Medical & Cancer Centers for Pets announces the re-launch of the organization’s website at as the preeminent source for access to veterinary emergency and specialty services to their network of 12 hospitals. The objectives of the new website are to integrate all locations while providing an easy location finder, to create an enhanced presence on the Internet for MedVet’s 24/7 emergency service and full complement of veterinary…

Read More