More dog breeds found to have high risk of breathing condition
Pekingese (left) and Japanese (right) dogs are at high risk of respiratory problems
Michael Schultze, KATAMOUNT/Alamy
Dog owners are being warned to be wary of a much wider range of breeds when buying puppies, following research showing serious respiratory disorders are more common than previously thought.
Dogs with shorter muzzles and flatter faces are known as brachycephalic breeds and have become “extremely popular” in recent years, says Francesca Tomlinson of the University of Cambridge.
But as the popularity of these breeds has skyrocketed, so have the health problems associated with them, particularly brachycephalic obstructive airway syndrome (BOAS), easily recognized by noisy breathing. This condition can lead to an inability to exercise, sleep, and cope with heat or stress.
Concerns about BOAS have primarily focused on English bulldogs, French bulldogs and pugs. To find out which other breeds are at risk, Tomlinson and his colleagues studied 898 dogs from 14 breeds: affenpinscher, Boston terrier, boxer, Cavalier King Charles spaniel, Chihuahua, Dogue de Bordeaux, Brussels Griffon, Japanese chin, Maltese, Pekingese, King Charles spaniel, Pomeranian, shih tzu and Staffordshire bull terrier.
All dogs underwent breathing tests and were subjected to a series of detailed body and facial measurements.
The Pekingese and Japanese chin had the highest risk of BOAS, with over 80% of dogs affected. Five breeds presented a moderate risk, with BOAS observed in half to three-quarters of dogs: the Cavalier King Charles spaniel, the shih tzu, the Griffon Bruxellois, the Boston terrier and the Dogue de Bordeaux. Only among the Maltese and Pomeranian breeds did they find any dogs with clinically significant disease.
Researchers found that three main factors led to respiratory problems: being overweight, narrowing of the nostrils and extreme flatness of the face. The analysis suggests that other traits, such as very short or screwed tails, may also be associated with BOAS-related anatomical changes. “This suggests that it is not just flatness that determines risk, but that many other factors come into play,” says Tomlinson.
She says potential owners should look for puppies whose parents have undergone appropriate health testing and should educate themselves about the potential health implications of extreme body changes, especially the face.
“It’s not necessarily about eliminating the defining characteristics of a breed, but about avoiding extremes and supporting breeding decisions that prioritize function as well as appearance,” she says.
Breeders need to know that it’s not just the breed that determines negative results, she says, but the degree to which certain physical traits are exaggerated. “This gives us something practical to work with – it suggests that moving away from the extremes could help reduce the risk of disease.”
Anna Quain of the University of Sydney, Australia, says people don’t appreciate that a “cute” and flat appearance predisposes these dogs to chronic oxygen deprivation and heat stress.
Breeding flat-faced dogs is like “designing a car without a radiator,” she says. “If we deliberately bring dogs into the world, we should base those decisions first on welfare rather than on preserving a human idea of what a dog should be.”
Paul McGreevy, also from the University of Sydney, says the study confirms what most veterinarians already know. “Airway compromise is prevalent in flat-faced dogs and varies greatly between breeds,” he says.
“For dogs that have difficulty excreting carbon dioxide through compromised airways, breed labels are irrelevant. Whether they are identified as a bulldog cross or registered as a Pekingese or Boston terrier is a human construct.”
He is, however, concerned about certain aspects of the methodology. “Assessment depends on subjective hearing of breath sounds classified by ear as mild, moderate or severe, but provides no evidence that this is applied consistently across 14 different breeds,” says McGreevy. “Even more problematic, the authors acknowledge that their stress test depends on the speed capacity and temperament of the individual.”
Tomlinson says the assessment incorporates objective criteria, including whether an abnormal breathing sound is audible with or without a stethoscope, and that scoring follows a standardized protocol. “The objective [of the exercise test] It’s not about evaluating sports performance, but about seeing how the airways react to light effort,” she says.
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