Health & Testing
BOAS in French Bulldogs: What Ethical Breeders Do to Improve Airway Function
BOAS affects the majority of French Bulldogs to some degree. Here's what responsible Frenchie breeders do to select for better airway function — and what to ask before buying.
June 1, 2024 · 6 min read
What Is BOAS?
Brachycephalic Obstructive Airway Syndrome (BOAS) is a collective term for anatomical abnormalities that obstruct breathing in flat-faced (brachycephalic) dogs. In French Bulldogs, the most common components include: stenotic nares (narrowed nostrils), elongated soft palate (extends too far back into the throat), hypoplastic trachea (abnormally small trachea), and everted laryngeal saccules (tissue pulled into the airway). Most French Bulldogs have some combination of these.
How Severity Is Assessed
- Clinical assessment by veterinarian: Evaluation of nostril size, breathing sounds, exercise tolerance
- BOAS functional grading (Cambridge scheme): Grade 0 (no signs) through Grade 3 (severe, continuous signs)
- CT evaluation: Advanced imaging to assess airway dimensions — used in serious research breeding programs
- Whole body barometric plethysmography (WBP): Objective airflow measurement — increasingly used in UK breeding programs
What Responsible French Bulldog Breeders Do
- Select breeding dogs with wider nostrils and more functional airways — even if they're slightly 'less extreme' in appearance
- BOAS test both parents before breeding — not just one
- Commit to functional breed type rather than extreme flat-face conformation
- Inform buyers honestly about expected respiratory health maintenance
What to Look for When Buying
Before purchasing a French Bulldog, ask to see both parents in person or via video, breathing during gentle activity. Signs of concern: loud snoring or snorting at rest, open-mouth breathing during mild exercise, blue-tinged gums after exertion, history of corrective surgery in the bloodline at young ages. A Frenchie that breathes quietly with nostrils of visible width at rest is significantly better off than one with audible respiratory sounds at rest.