Around 150 years ago, bulldogs were much different. They were slender-legged, with a longer snout and a livelier demeanor.
Today, it's nearly impossible for a purebred bulldog to reproduce without assistance. Most have to be artificially inseminated since the female cannot support the male's weight during mating. Eighty percent of bulldog puppies are delivered by caesarian section; their signature large, flat heads are simply too large for the birth canal. Many bulldogs also struggle with breathing problems on account of their stubby noses, and 71.6 percent have hip dysplasia, an abnormal formation of the hip socket that often results in painful arthritis or even lameness.
The bulldog isn't the only breed of canine facing health issues. Up to one-third of Cavalier King Charles Spaniels have a skull that's too small for their brains. In a 2009 BBC One documentary, veterinary neurologist Dr. Claire Rusbridge described the brain as a "size 10 foot that's been shoved into a size 6 shoe." Around 38.5 percent of boxers die from cancer. The ears of basset hounds are so long that, as puppies, they trip over them and accidentally chew on them while eating.
The blame for all of these health problems lies squarely with the leash holder. Through years of highly questionable breeding practices, humans have bred the genetic diversity out of a great many dogs, almost entirely for cosmetic reasons. As dogs lose their hybrid vigor, deleterious genetic traits seep in and grow commonplace. Man is inadvertently sabotaging his best friend.
A study published in 2008 in the journal Genetics drove this point home. Examining breeds like boxers, chows, bulldogs, golden retrievers, greyhounds, and Labradors, the research team discovered that in just six generations of breeding, the dogs had lost 90 percent of their genetic variation. Nine of the 10 breeds studied were extremely inbred. The only one that wasn't was the greyhound.
In 2013, scientists from the University of California-Davis examined the prevalence of 24 genetic disorders, including various types of cancers, orthopedic problems, allergies, cataracts, and epilepsy, in 90,000 mixed-breed and purebred dogs. They found that 13 of the 24 disorders occurred at comparable levels in each group, 10 were found more frequently among purebred dogs, and only one was more common among mixed breeds.
A more recent study found that inbreeding reduced longevity and reduced litter size in seven French dog breeds.
Dr. Patricia McConnell, an applied animal behaviorist, dog expert, and a professor at the University of Wisconsin-Madison, is not a fan of this unfortunate situation.
"Heaven help me, because I know I'll take flack for this, but as a biologist and a dog lover, I just have to comment that there is something terribly wrong with the way we are defining 'purebred' dogs now," she wrote.
She has some ideas about how to fix our pooches' predicament. One of them is to do away with the dogmatic, idealized notion of "purebred."
"Insisting on 100 percent 'purity' of blood lines is relatively new: It was common in the past, less than 100 years ago, to mix and match lineages and breeds to combine desired traits and keep the lines healthy,"she said. "The idea of bringing in new genetics, if necessary, was considered to be a good thing, not something that would destroy the breed."
Another is to take a science-based approach to purebred breeding. One of the biggest problems is the sire phenomenon, where popular male dogs are mated to a host of females. This practice should be limited. Genetic testing is also becoming increasingly available and affordable. The best breeders, like the Seeing Eye in Morristown, N.J., keep a genetic database for all their dogs and actively monitor and enhance the gene pool.
Of course, if dog breeders are going to enact needed changes, they need to be pressured by consumers. Dog buyers are frequently unable to see past the floppy ears and big eyes of adorable puppies to the underlying health of the animals. Potential owners of purebred dogs must educate themselves on genetics and purchase only from responsible breeders.
Editorial on 01/25/2015