18/09/2025
➡Risk factors for Brachycephalic Obstructive Airway Syndrome
➡How can we avoid extreme conformation and breed for longevity, health and welfare in brachycephalic dogs?
💬Conformational risk factors of brachycephalic obstructive airway syndrome (BOAS) in pugs, French bulldogs, and bulldogs
https://pmc.ncbi.nlm.nih.gov/articles/PMC5538678/
We all know that many brachycephalic breeds are appealing to prospective owners, and although the trend of buying these breeds is reducing slightly they are still incredibly popular. Because of their popularity, breeders who are working hard to breed flat faced breeds with less extreme conformation and improved health cannot keep up with demand - so unscrupulous and unethical breeders take their place.
We know that brachycephalic dogs have health conditions linked to their conformation. We should be doing everything in our power to breed away from these issues.
Take a look at the study above, it is interesting to note that within the breeds seen, BOAS risk factors varied!
Although brachycephalic dogs can include, but not limited to, English Bulldog, French Bulldog, Pug, Chihuahua, Shih Tzu and more there are breeds within this group of flat faced breeds who are 1) experiencing a trend of extreme breeding and public desire for extreme conformation and 2) experience different issues associated with brachycephalism.
For example, we know that these issues are not simply just related to Brachycephalic Obstructive airway syndrome but also some of these breeds may be more predisposed to dystocia, spinal/ neurological disorders (linked to the bob or corkscrew tail), ocular disorders, sleep disorders and skin disorders.
Again, there are some breeds typically not associated with brachycephalism that are also presenting with BOAS, and even within these brachycephalic groups there risk factors can vary.
BOAS can be related to a number of conformational issues such as mega glossa, inverted saccules, stenotic nares, soft palate obstructions, chondromalacia of larynx and more.
If we can understand the conformational risk factors we can start to work towards breeding these dogs for healthier conformation. This includes ensuring they have a tail, open nares, elongating the snout while also trying to ensure that this correlates with internal structure positive change.
This study also bring up factors such as eye width, neck length and shoulder width as possible factors (and various ratios associated with these measurements).
Therefore when looking to pick a puppy, we can look at their features alongside health tests to ensure that breeders are making positive change in their breed.
➡Pugs
Among the direct measurements, the BOAS (+) dogs had significantly greater eye width. Pugs with moderately/severely stenotic nostrils had greater odds of being BOAS (+) than those with open/mildly stenotic nostrils. There was a clear trend that the higher the functional grade, the higher the proportion of high-BCS
Conformational factors EWR (Eye width ratio (EWR): eye width / skull width and Skull index (SI): skull width/ skull length were significantly associated with BOAS after adjusting for other factors. There was a tendency for dogs with higher EWR and SI to be more likely BOAS (+)
➡ French Bulldog
French bulldogs that had moderately/severely stenotic nostrils had greater odds of being BOAS (+) than those with open/mildly stenotic nostrils. Neck girth ratio (NGR): neck girth (NG) / chest girth (CG) was significantly associated with BOAS in French bulldogs.
➡ English Bulldog
Neuter status, stenotic nostrils, and neck girth (NG) / chest girth (CG) (NGR) were significantly associated with BOAS index.
➡ Other considerations
Have you viewed the mum and puppies together in a home environment (multiple times)?
Have they all been microchipped before leaving?
Has dam and sire been health tested?
Have they received appropriate preventative care?
Have they both had a 'Respiratory Function Grade' done, at least within the last 1-2 years?
Did they whelp naturally?
Can you hear mum or dad breathing loudly when at rest?
Do they have excessive skin folds?
➡ Remember, you may have your heart set on one of these breeds, and if you are prepared to care for their needs, then you may consider getting one.
But you must NOT fuel the irresponsible (and sometimes illegal) breeding of these dogs with poor health and welfare. Please, pick the breeders who are trying to improve their dogs to become healthier and have less extreme conformation.