by Alina Lilova

When dog fanciers breed a Hush Puppy (Basset hound) to look like what it’s ‘supposed to,’ they may be inadvertently putting him at high risk from developing the skeletal disorder known as hip dysplasia – one of the plagues of the purebred dog world. Severe hip dysplasia can cause osteoarthritis and be very painful, even crippling to the animal. Many breeders try to prevent the disease by evaluating the radiographs of potential parent dogs and excluding some affected animals – with moderate success. Unfortunately, their efforts are bound to remain half-hearted, as long as aesthetic preferences dictate that the most visually appealing dogs are those in danger of falling ill, according to a new study.

Scientists Taryn Roberts and Paul McGreevy examined breed scores for hip dysplasia published by several major organisations along with the body length-to-height ratios of 30 breeds. They wanted to see whether the physical proportions prized in the show ring were also good for the dogs’ health. To that end, for each breed, they used photographs of twelve victorious pooches who had been awarded a “Best of Breed,” measured their relative body lengths, and compared them to what was known about the prevalence of hip dysplasia in the breed.

Best-of-Breed Doberman, photo by Paul McGreevy

It turned out that longer dogs are on average eight times more likely to be affected than the more square-bodied breeds. Selecting for heavy rectangular dogs is especially dangerous, hence the severity of this problem in breeds such as the Neapolitan Mastiff and the St. Bernard.

The scientists felt that “drastic revisions” of the breed standards were needed – not only standards that specifically require the ‘ideal’ dog to be longer than he’s tall at the withers, but also those that are vague about proportions. The latter leave too much room for interpretation to breeders and judges whose personal preferences may not be in the dog’s best interest at all.

Source:

Roberts, T., McGreevy, P.D. Selection for breed-specific long-bodied phenotypes is associated with increased expression of canine hip dysplasia. The Veterinary Journal (2009), doi:10.1016/j.tvjl.2009.11.005