Brachycephalic obstructive airway syndrome (BOAS) is a serious respiratory condition that affects brachycephalic dog breeds with shortened snouts. This disorder arises due to extreme facial flatness resulting from selective breeding, which leads to difficulty breathing and can negatively impact a dogs quality of life and lifespan. In the United States, well-known breeds such as Pug puppies, French Bulldog puppies, and English Bulldog puppies are particularly susceptible to BOAS due to breeding that favors overly flat faces.
Veterinarians in the U.S. utilize a standardized grading system to assess BOAS, developed to offer consistent evaluation of airway function in affected dogs. Each dog receives two key assessments: a functional BOAS grade and a nostril grade. These measurements assist caregivers and veterinarians in understanding the degree of airway obstruction, guiding both care decisions and responsible breeding practices.
The functional BOAS grade evaluates a dogs breathing at rest and following an exercise tolerance test, since symptoms tend to worsen with physical activity. Grades range from 0 to 3, where 0 represents no respiratory issues and 3 indicates severe airway compromise.
Nostril grading evaluates how open or constricted a dogs nostrils are, a critical factor affecting airflow and overall breathing comfort. Narrow nostrils raise resistance in airflow, exacerbating BOAS symptoms.
Wide-open nostrils that are healthy for the breed, allowing excellent airflow.
Some narrowing of nostrils exists; however, they can open sufficiently during exercise without causing breathing difficulties.
Moderately narrowed nostrils that restrict airflow. They remain open only at the lower rim and do not flare during activity, often leading to mouth breathing.
Severe narrowing or almost complete closure of the nostrils, causing mouth breathing even while resting or after minimal effort.
Being familiar with your dogs BOAS and nostril grades is essential to ensuring proactive, responsible care. This knowledge helps veterinarians and pet owners decide if your dog needs special care routines, lifestyle modifications, or surgical interventions to improve breathing. For breeders in the U.S., these grades serve as crucial criteria to avoid producing dogs with severe airway issues, thereby improving the respiratory health of future litters.
Leading veterinary and welfare professionals in America strongly support using such grading systems to encourage ethical ownership and breeding. Since 2025, noticeable events such as the AKC national dog shows have begun requiring participating Pugs, Bulldogs, and French Bulldogs to have up-to-date respiratory function grading, emphasizing health over physical appearance.
If youre thinking about adopting or purchasing a brachycephalic dog breed in the U.S., its wise to research thorough health screening and select reputable breeders prioritizing airway health instead of exaggerated features. This approach increases the likelihood of a pet with fewer breathing problems and a better quality of life.
Responsible pet care includes regular visits to your veterinarian, especially from an early age, careful monitoring of breathing patterns, avoiding excessive exercise or heat exposure (consider the hotter, humid summers in parts of the U.S.), and watching for signs of respiratory distress. If your dog is diagnosed with BOAS, work closely with a veterinary professional to tailor a care plan that suits your dogs specific needs.
This guide has clarified the evaluation of BOAS and nostril grades, equipping you with the understanding needed to provide attentive care for your brachycephalic companion. Supporting responsible breeding and ownership helps improve the health and wellbeing of these beloved breeds across America.