By Dr. Chris Duke
Knight Ridder Newspapers
A fringe benefit I often mention when clients adopt mixed-breed dogs from shelters is that, by and large, predominantly mixed breeds of dogs live longer lives than purebred dogs of established lineage.
A geneticist would refer to the concept as "hybrid vigor," or a survivability factor that toughens up an individual of mixed breeds.
While practitioners such as myself have thrown around this concept in generalities, an academic study has now documented this principle as truth.
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A Danish study found that mixed-breed dogs on average live one year longer than their purebred counterparts.
The study, reported in the April 2003 issue of Preventive Veterinary Medicine and reprinted in the June 2003 issue of Veterinary Forum, found the average life span for a mixed breed is 11 years.
The average life span for purebreds is 10 years.
Nearly 3,000 dogs were included in this study, representing 20 breeds, 15 breed groups and a mixed-breed population.
The purebreds found to have the shortest life span were the Bernese mountain dog, Rottweiler and all sighthounds. The average age at death for these breeds was only 7 years.
The purebreds found to have the longest life spans were the Shetland sheep dog, all poodles and the dachshund.
True to what we see here in America, there was a correlation of smaller breed of dogs living longer versus their large-breed counterparts.
The study was authored by Helle Friis Proschowsky of Denmark's Royal Veterinary and Agriculture University.
