Why You Don't Want a Flat-Faced Pet

by Brian Dunning
April 19, 2022

Dogs are the best humans ever, and cats can make the best self-sufficient warm purring teddy bears. Most of us love one or the other or both, and we've bred them over the centuries to better fit our notions of what looks good or cute. In some cases this has produced breeds that are short nosed, sometimes to the point of being flat faced with no protruding nose or snout at all — think of a dog like the pug or a Persian cat. The anatomical term is brachycephaly — literally "short head" — and it's a trait that many enthusiasts of pedigreed dog and cat breeds strive for. However, if you're aware of these breeds, you have likely also heard the claim that brachycephalic breeds have inherent health problems, mainly that they live their entire lives in a state of inescapable respiratory distress; to the point that quite a lot of animal welfare activists consider these animals to be essentially tortured. This lays the groundwork for a fundamental conflict between animal breeders and purebred associations, and the animal welfare community. Today we're going to have a look at where the lines of this battle should be drawn by science, and find out how much truth there is to this claim.

As any veterinarian will tell you, the condition is a real one, and it's called brachycephalic obstructive airway syndrome, or BOAS — note that in various regions you may hear variations on this name, but for consistency's sake BOAS is the one we'll go with today. Short nosed dogs and cats do not automatically all have BOAS, but they are at greatly increased risk for it; breeds that are not brachycephalic are at very low risk of having it. The signs of BOAS can include noisy or labored breathing, snoring, lack of ability to tolerate exercise, and a risk of collapsing or fainting after exercise. If your pet has these signs, a vet can easily assess them to see if they have BOAS; and if they do, it may be possible to improve your pet's quality of life with corrective surgery.

There are three basic anatomical defects associated with BOAS, all stemming from the fact that the animal's snout is genetically positioned way back into its face. The same structures are all present as in a normal animal, but with such little room available, the structures can be distorted and jumbled up. The first of these defects is also the most easy to spot, and it's at the nostrils. Animals with BOAS have their facial structures compressed into a smaller space, and this often results in nostrils that are slitlike, almost closed off, making it much harder for the lungs to pull in oxygen. The second of these defects is more dramatic, and it's that the animal's soft palate, at the back of the roof of the mouth, is pushed back far enough that its tip extends into the larynx. Normally it's supposed to terminate well above the larynx, allowing free flow of oxygen into the lungs. But when the soft palate extends into the larynx, the animal has to struggle with each breath, breathing in more forcefully to pull the oxygen past the obstruction. The third defect is a result of the second, and that's that if the lungs have to work too hard too often to pull in that oxygen past the soft palate, the chronic sucking can actually collapse the larynx. The first two defects can be corrected surgically; but if the larynx collapses, there is much less that can be done.

Except on the pads of their feet and their noses, dogs and cats lack the type of sweat glands that can keep them cool, so they regulate their body temperature by panting. An animal with BOAS is unable to pant adequately for thermoregulation; so while the inability to get enough oxygen is their main problem, the inability to cool their bodies when overheated is a close second — and in very hot conditions, pets with BOAS have a dramatically increased risk of death from heat stroke.

None of that is controversial or in any dispute. If you have a brachycephalic pet, the advice is universally to have it tested for BOAS and follow the vet's advice on how your pet can be made most comfortable. Where the controversy comes in is the cause of BOAS. Most, including vets and scientists, say that it's purely due to the genetics of short nosed dog and cat breeds; and others — primarily the breeders and major kennel clubs — claim that it's multifactorial, acknowledging its genetic and structural roots but also pinning some of the blame on environmental triggers. I searched all the academic literature I could, and found exactly zero environmental causes for BOAS.

The simple fact is that it's purely a genetic defect that breeders have introduced. And it's not the only one. Common wisdom has long held that dogs of mixed breed are generally healthier than purebred dogs, as they tend to be more free of genetic defects. Supporting this was a major study published in 2015 in the Journal of the American Veterinary Medical Association that studied more than 90,000 dogs: 27,000 dogs with inherited genetic disorders along with 63,000 healthy control dogs that matched for age, body weight, and gender. That's a lot of dogs, and a lot of data.

24 inherited genetic disorders were assessed. Just over half — 13 of them — were found equally in all dogs, purebred or not. But the remaining 11 disorders showed a strong correlation with breeding. Only one inherited genetic defect studied — the tendency toward a ruptured cranial cruciate ligament — was found more often in mixed breed dogs. All of the rest turned out to be the domain of purebreds, including:

• Aortic stenosis
• Dilated cardiomyopathy
• Elbow dysplasia
• Intervertebral disc disease
• Hypothyroidism
• Atopy or allergic dermatitis
• Bloat
• Cataracts
• Epilepsy
• Portosystemic shunt

In their discussion, one of the points the authors made was that "Some disorders may require breed registry intervention to reduce conformational selection pressures that contribute to predisposing a breed to a disorder." This seems a rational step for the breed registries to take, so let's have a look at how they responded when legislation started to appear that drove them to look into this.

The most notable case of this happening was triggered by some new legislation regarding brachycephalic breeds in the Netherlands in 2014. As enforcement began, the Dutch Kennel Club reacted in 2020 by limiting the number of new registrations of twelve breeds of brachycephalic dogs, predictably prompting outcries from the breeders who depend on that. The World Canine Organization published an open letter expressing their dismay. I had hoped that this letter would put forth science based arguments in favor of brachycephalic breeds — link to some study data or something — or otherwise show that the dogs' interests were best being served by continuing to grow these breeds. No such luck. The overall tone of the letter, and of the corresponding letter from the American Kennel Club which we'll get to in a moment, is shockingly disdainful of these dogs' suffering, especially considering that it's coming from people who have devoted their lives to dogs. They speak of history and heritage like one would speak of precious commodities, displaying no awareness of the dogs' wellbeing or care. The letter speaks only of the quality of the gene pool (language that sounded a little too reminiscent of World War II) and the importance of the national heritage of these breeds; even going so far as to use the phrase "cheating hundreds of years of history" (language that could have come from advocates of Confederate general statues in the southern US). The closest the letter ever got to the welfare of the dogs was that limitations on registrations may drive more of that breeding underground to unregulated puppy farms — likely true, but an argument also plainly in their own financial interest.

The American Kennel Club also published a statement. It characterized the Dutch decision as "rooted in a radical animal rights/anti-breeding viewpoint" and charged that organizations pushing such legislation "almost universally equate breeding with animal cruelty." Now, it's fair to point out that there is indeed quite a lot of over-the-top anti-breeding sentiment coming from a radical animal rights fringe that goes far beyond any science; PETA being the most obvious example with their various oddball beliefs like all pet ownership being slavery, and drinking cow's milk causes autism. But looney-tune extremism cannot intelligently be equated with science-based efforts to understand and prevent animals from living in perpetual respiratory distress. It's a case where the conversation could have been made much more productive by stripping away hyperbolic attacks and sticking to the common goals.

In a token example of this, the AKC letter did allude to "scientific discussion of thoughtful ways to address health issues within a breed in a way that protects and preserves the essence of the breed." Even though it's qualified with "as long we still get our flat-faced pets," at least this is a mention of the animals' own welfare. So is there any such research going on?

There is, a bit. Some amount of genetic research is being devoted to goal of separating the flat face, which the market of pet owners demands, from the associated respiratory problems. Why do some short nosed pets suffer from BOAS while others don't? Can a genetic solution be found? A team at the Cambridge Veterinary School has a long-term project studying genetic samples from brachycephalic dogs. What have they found so far? According to their publications, no genetic solutions. No magic way to breed away the BOAS while keeping the cute flat face. This doesn't mean they won't find one tomorrow, but most of what they've been able to do is to improve testing for BOAS and to develop better surgical repairs.

BOAS is not the only medical problem associated with brachycephalic breeds. The compressed face usually includes eyes that protrude more than normal, robbing them of the protection of the bones surrounding the eye socket. This leaves their eyes susceptible to injury and often results in dry eyes and problems with the shape of the eyelid, all of which impact the quality of life. As far as the mouth goes, dental crowding and tooth misalignment is practically guaranteed — same number of teeth, but less room for them to fit. Your vet may recommend extracting some teeth. If these conditions are not something you want your best little fur friend to live with, you might choose not to support the ongoing production of animals with genetic defects that put them in significant discomfort, and instead choose a friend with a natural and healthy face shape.

For a thousand years, Chinese had a custom of breaking and binding the feet of young girls to force them into a deformed shape that was considered the epitome of beauty and status. In addition to experiencing lifelong pain, such women were susceptible to all manner of related problems from infection to paralysis to bone and muscular problems. It's been estimated that as many as 10% of girls died from sepsis caused by the binding process. Today such a practice would be deemed barbaric, as it unambiguously fits any definition of torture. I challenge anyone to convincingly argue that the deliberate breeding of brachycephalic animals is any different from foot binding. If you want a pet to be your partner, be a worthy partner to them first.

By Brian Dunning
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