Can your pet breathe properly?


BOAS (Brachycephalic Obstructive Airway Syndrome)

Our furry friends with short noses (known as brachycephalics) are at risk of BOAS, which is a severe life limiting disease. 50% Pugs, French bulldogs and 45% of English Bulldogs are affected.

The breathing problems they exhibit are due to the shortened skull. The length of the nose is reduced but the same amount of soft tissue is compressed into this smaller area leading to obstruction of the throat, making breathing difficult.

The excess soft tissue in the throat causes an increased resistance to breathing and requires more effort to breathe and overcome the obstruction to get air into the airways.

Signs of BOAS

  • Snoring (either asleep or awake)
  • Nasal noise
  • Reverse sneezing
  • Exercise intolerance
  • Heat intolerance
  • Bluish discolouration tongue when active (cyanosis)
  • Sleep disorders
  • Collapse

If you dog exhibits any of the above noises when breathing then he/she maybe suffering with BOAS. If breathing noise is marked then it is recommended that you seek veterinary advice and get him/her tested for BOAS via a simple Exercise Tolerance Test.


Often seen as ‘normal’ or cute, excessive snoring either whilst asleep or awake is a sign of a breathing problem. Due to a thickened tongue base and soft palate (tissue on the roof of the mouth) snoring occurs when this tissue vibrates and creates a noise. This can lead to breathing difficulties when sleeping and potentially a period of time when breathing stops (sleep apnoea).

Nasal noise

Narrowed nostrils lead to reduced airflow through the nose and dogs with severely stenotic or narrowed nostrils are 20 times more likely to develop BOAS

Normal appearance of the nostrils

Severely stenotic nares

Reverse sneezing

This noise that sounds like sucking air into the nose rather than expelling it (i.e. sneezing). It is thought to be due to an overlong soft palate (tissue on the roof of the mouth).

Heat intolerance

A dog’s nose helps regulate body temperature. Air passing in through the nostrils and throat/mouth helps to cool the body via the evaporation of moisture and saliva. Dogs with a very short nose and increased resitance to airflow can’t regulate their body temperature efficiently and are prone to overheating.

Cyanosis and collapse

In severe cases lack of oxygen getting into the airways can cause collapse and is an emergency.

Risk factors for BOAS

Body conformation factors:

Certain factors increase the risk of an animal being affected BOAS

  • Increased thickness of the neck and a shorter neck
  • Narrowed (stenotic) nostrils
  • Obesity
  • Wider and shorter skulls
  • Shorter nose
  • Pugs: wider distance between eyes


To diagnose whether your pet has BOAS a veterinarian needs to perform a clinical examination. This will include a weight check, full clinical examination and an Exercise Tolerance Test.

Exercise tolerance test

This involves a 3 minute trot at a speed of 4mph and repeat examination after the exercise, which is designed to stress the breathing system.

BOAS affected animals are Graded from 0 (not affected) to III (severe signs requiring surgery)

Blake Vets are now offering Exercise Tolerance Testing. The first 10 clients to book will receive the consultation including exercise tolerance testing free of charge.


More information on BOAS is available at: www.vet.cam.ac.uk/boas










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