The Kennel Club and University of Cambridge's Respiratory Function Grading Scheme assesses Bulldogs, French Bulldogs and Pugs for a breathing problem known as BOAS (brachycephalic obstructive airway syndrome).
Brachycephalic obstructive airway syndrome is the term given to the effects that the shortened head of these animals has on the passage of air through the upper airways. The signs can vary in severity from mild snoring or snorting noises to severe breathing problems.
Animals suffering from clinically significant BOAS can struggle to breathe during exercise and may suffer collapse due to lack of air. The reliance of dogs on panting to cool themselves also makes animals suffering from BOAS very susceptible to overheating and developing potentially very serious breathing difficulties in hot conditions.