Brachycephalic Dog Health and Welfare
- veterinaryvoicesuk
- May 15, 2022
- 9 min read
Updated: Mar 18
Under UK animal welfare legislation, there is a clear legal and ethical responsibility when it comes to breeding dogs:
“No dog may be kept for breeding if it can reasonably be expected, on the basis of its genotype, phenotype or state of health, that breeding from it could have a detrimental effect on its health or welfare or the health or welfare of its offspring.”— Dog breeding licensing: statutory guidance for local authorities (Section 6.5)
This regulation exists to protect dogs from preventable suffering. Yet, despite this, it is unenforceable, and many brachycephalic (flat-faced) breeds continue to be bred in ways that compromise their health and welfare.
While these dogs are loved for their personalities and appearance, we must acknowledge a difficult truth: many of the features we find “cute” are directly linked to serious, often lifelong health problems.
Aesthetic Breeding vs Welfare
Brachycephalic breeds—such as French Bulldogs, Pugs, and English Bulldogs—have been selectively bred for exaggerated facial features. Unfortunately, these extreme conformations often come at a significant cost.
Unethical breeding practices not only harm the dogs themselves but also undermine the efforts of responsible breeders who are working to improve health and conformation.
We can appreciate the joy these dogs bring while still recognising the urgent need to prioritise health over appearance.
Eye Disease: More Than Just “Big, Cute Eyes”
The large, prominent eyes typical of brachycephalic breeds are not just a cosmetic feature—they are a medical concern.
Brachycephalic Ocular Syndrome (BOS) arises from these exaggerated facial structures and can lead to a range of painful and vision-threatening conditions.
Common anatomical issues include:
Macroblepharon (overly large eyelid openings)
Excessively long palpebral fissures
Lagophthalmos (inability to fully close the eyelids)
These abnormalities prevent proper protection and lubrication of the eye surface, leading to:
Eye trauma
Exposure keratopathy (corneal disease)
Pigmentary keratitis (chronic inflammation and pigmentation)
Corneal erosion and ulceration
These are not minor issues—they can result in chronic pain and even loss of vision.
The Zero Pain Philosophy stated: 'Blinking is an innate and essential bodily function. One that is critical for maintaining ocular surface health. And extreme conformations, like ectropion or “diamond eye”, prevent the normal distribution of tears, so disrupt this important eyelid function. What these pets then have is an eye surface that is less lubricated, and therefore not adequately protected. These exposed and drier eyes are prone to developing secondary conditions such as inflammation, damage, ulcers…and don’t forget pain. The corneal surface is one of the most innervated tissues in the body. Poor conformation causing ocular disease causes pain, and when chronic this pain is also chronic. As veterinary professionals, we all recognise the signs of ocular pain - squinting, or excessive blinking, and rubbing or pawing at their eyes.'
Sleep Deprivation: A Hidden Welfare Concern
One of the lesser-known impacts of brachycephaly is chronic sleep disturbance.
Studies suggest that brachycephalic dogs experience poorer sleep quality, often linked to Brachycephalic Obstructive Airway Syndrome (BOAS). Many owners may not recognise this as abnormal. Behaviours often perceived as “cute”—such as dogs falling asleep with toys in their mouths—are actually coping mechanisms. These dogs may prop their mouths open to help maintain airflow while sleeping. This is not normal. It is a sign of compromised breathing and welfare.
Sleep disturbance in brachycephalic dogs is an increasingly recognised but still underappreciated welfare concern. While dogs naturally sleep in cycles throughout the day, their most important, restorative sleep occurs at night, and it is the quality of that sleep that matters most.
In many brachycephalic dogs—particularly those affected by Brachycephalic Obstructive Airway Syndrome (BOAS)—this sleep is significantly disrupted. Similar to obstructive sleep apnoea (OSA) in humans, these dogs may experience loud snoring, episodes of paradoxical breathing where the chest moves but little or no air is entering, followed by gasping or choking as they wake themselves to re-establish airflow. This occurs because dogs are obligate nasal breathers during sleep, yet structural abnormalities such as stenotic nares, elongated soft palate, thickened tongue, and overcrowded nasal turbinates can obstruct or occulde the airway. As the airway narrows or collapses during sleep, negative pressure builds and the dog is forced to repeatedly wake, preventing restorative rest.
As a result, many dogs adapt by sleeping with their mouths open, propping their heads up, or even falling asleep sitting or standing—behaviours often mistaken as normal or even “cute,” but which are in fact coping mechanisms. As in humans, chronic sleep disruption is associated with significant health consequences, and emerging evidence suggests similar impacts on physical and neurological wellbeing in dogs. Despite this, sleep disturbance in brachycephalic breeds remains under-recognised, highlighting the need for greater awareness.
Brachycephalic Obstructive Airway Syndrome (BOAS)
BOAS is one of the most significant and most talked about health issues affecting these breeds.
As dogs are bred for shorter muzzles, the soft tissues within the skull do not reduce proportionally. This creates overcrowding and obstruction within the airway.
Common structural abnormalities include:
Stenotic nares (narrowed nostrils)
Overcrowded or aberrant nasal turbinates
Elongated and thickened soft palate
Hypoplastic trachea (narrow windpipe)
The result is restricted airflow, causing:
Breathing difficulties
Exercise intolerance
Increased risk of overheating
Secondary impacts on heart function and temperature regulation
Many affected dogs require surgical intervention simply to breathe more comfortably.
Neurological and Spinal Disorders
Health concerns in brachycephalic breeds extend beyond breathing and eyes.
Syringomyelia
Particularly common in Cavalier King Charles Spaniels, this condition involves fluid-filled cavities within the spinal cord, leading to:
Abnormal sensations
Severe, often excruciating neck pain
Spinal Deformities
Screw-tailed breeds such as French Bulldogs, Pugs, and English Bulldogs are prone to vertebral malformations, including:
Hemivertebra (misshapen vertebrae)
Kyphosis (abnormal forward curvature of the spine)
Scoliosis (sideways curvature of the spine)
These conditions can result in pain, mobility issues, and neurological deficits.
The Financial and Emotional Cost
Veterinary professionals frequently encounter owners who have purchased expensive puppies without fully understanding the potential long-term health implications.
Many of these conditions are not incidental—they are directly linked to the dog’s conformation. This can lead to ongoing emotional distress for owners and significant financial burden due to lifelong treatment needs.
Old and New Research on BOAS in Brachycephalic Dogs
Brachycephalic (flat-faced) breeds such as French Bulldogs, Pugs, and English Bulldogs remain hugely popular. Other breeds including Boston Terriers, Pekingese, Shih Tzu and Japanese Chins also fall into this category and continue to be widely loved for their appearance and character.
However, this popularity persists despite increasing awareness of the significant health challenges these dogs can face—particularly Brachycephalic Obstructive Airway Syndrome (BOAS).
Demand for these breeds often exceeds the supply of responsibly bred puppies. As a result, unethical breeding practices continue, reinforcing extreme conformations and perpetuating poor health outcomes. This makes it critical that we understand the true risk factors behind BOAS and use this knowledge to support healthier breeding decisions.
What Earlier Research Told Us (2017 Study)
A 2017 study examining conformational risk factors for BOAS in:
Pugs
French Bulldogs
English Bulldogs
confirmed that BOAS is strongly linked to physical characteristics—but importantly, risk factors differ between breeds.
Key findings:
Pugs
Narrow nostrils significantly increased BOAS risk
Wider eyes and broader skulls (high Eye Width Ratio and Skull Index) were strongly associated with disease
French Bulldogs
Moderate to severe stenotic nares greatly increased BOAS risk
A thicker neck relative to chest size (high Neck Girth Ratio) was linked to more severe disease
English Bulldogs
Narrow nostrils increased BOAS risk
Higher neck-to-chest girth ratios were associated with worse outcomes
Neutered dogs showed increased BOAS association (potentially linked to post-neutering weight gain and obesity)
Study: Conformational risk factors of brachycephalic obstructive airway syndrome (BOAS)https://pmc.ncbi.nlm.nih.gov/articles/PMC5538678/
Looking Beyond the Surface: Internal Anatomy Matters
More recent research has highlighted that BOAS is not just about what we see externally. A comprehensive CT-based study examined anatomical risk factors from the nostrils through to the cervical trachea.
This research demonstrated that internal airway structure plays a critical role, and again, findings varied by breed.
Key insights:
BOAS lesions differ significantly between Pugs, French Bulldogs, and Bulldogs
In Pugs, intra-nasal obstruction and advanced laryngeal collapse predicted severity
In French Bulldogs, nasopharyngeal dimensions and laryngeal collapse were key predictors
In Bulldogs, tracheal hypoplasia and broader skull shape were strongly associated with severity
Some conditions, such as hypoplastic trachea in Bulldogs, are not surgically correctable and should be addressed through selective breeding
Methods used:
Objective BOAS testing
Whole-body plethysmography (BOAS index)
CT imaging of the airway
Measurement of 11 anatomical features
Study: Breed-specific anatomical risk factors of BOAS: a comprehensive CT studyhttps://doi.org/10.1016/j.tvjl.2025.106484
New 2026 Research: A Broader Population Perspective
A major UK study published on 18 February 2026 by the University of Cambridge examined BOAS prevalence across 14 brachycephalic breeds using adapted Respiratory Function Grading (RFG).
Breeds included:
Affenpinscher, Boston Terrier, Boxer, Cavalier King Charles Spaniel, Chihuahua, Dogue de Bordeaux, Griffon Bruxellois, Japanese Chin, King Charles Spaniel, Maltese, Pekingese, Pomeranian, Shih Tzu and Staffordshire Bull Terrier.
Key findings:
BOAS severity varies widely between breeds
Pekingese and Japanese Chins had some of the highest rates of clinically affected dogs
Only 10.9% of Pekingese were Grade 0 (clinically unaffected)
Only 17.4% of Japanese Chins were Grade 0
Across all breeds, three major risk factors were consistently linked to worse BOAS:
Higher Body Condition Score (obesity)
Nostril stenosis (narrowed nostrils)
Lower craniofacial ratio (more extreme facial shortening)
Interestingly, not all flat-faced breeds were equally affected:
Pekingese and Japanese Chins: high risk
Boston Terriers and Shih Tzu: moderate risk
Chihuahua and Boxer: lower risk
What This Means for Breeding
Across all studies—old and new—the message is consistent:
BOAS is not inevitable, but it is strongly influenced by breeding choices.
To improve welfare, breeding priorities should include:
Open, functional nostrils
Longer, more functional muzzle and airway space
Awareness of internal airway anatomy (not just appearance)
Healthy neck and body proportions
Avoiding extreme traits such as corkscrew tails
Maintaining a healthy body condition
Respiratory Function Grading (RFG) before breeding
Use of validated health testing tools
What to Ask When Choosing a Puppy
If you are considering a brachycephalic breed, asking the right questions can make a significant difference:
Have both parents had recent Respiratory Function Grading (ideally Grade 0)?
Can the parents breathe quietly at rest?
Did the dam give birth naturally?
Are there excessive skin folds or extreme facial features?
Can you meet the puppies multiple times in a home environment?
Are all health tests and preventative care up to date?
Would the parents raise concerns on an Innate Health Assessment?
The Innate Health Assessment (IHA) is designed to support responsible breeding by evaluating whether a dog is suitable for breeding based on its inherent health characteristics.
Moving Forward
It is entirely possible to love brachycephalic breeds—and many people do.
But loving these dogs should mean supporting:
Responsible breeders
Evidence-based improvements
Health-led selection over extreme appearance
Because ultimately, improving the future of these breeds depends on informed decisions—by breeders, professionals, and owners alike.
Where Do We Go From Here?
Brachycephalic dogs face a wide range of health challenges, including:
Eye disease
Respiratory compromise
Sleep disturbance
Neurological and spinal disorders
Heat stroke
Dystocia (difficulty giving birth)
Increased susceptibility to infections such as pneumonia
Despite this, demand for these breeds continues to rise.
We are at risk of normalising poor health.
Veterinary professionals and welfare organisations continue to educate and advocate for change—but progress depends on public perception.
If appearance and “character” continue to outweigh health and longevity in decision-making, meaningful change becomes increasingly difficult.
A Call for Change
This is not about blaming owners—it is about awareness and responsibility.
We must:
Support ethical breeders prioritising health
Challenge the normalisation of unhealthy traits
Make informed choices when selecting a pet
Shift the focus from appearance to welfare
Because ultimately, no dog should suffer for the way it looks.
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