serious health problems
Unfortunately, whilst the skull of brachycephalic dogs has shortened drastically the soft tissues of the face and mouth have not shrunk sufficiently to adapt to the reduced space. These soft tissues include the soft palate (the fleshy part of the roof of the mouth), turbinates (cartilage inside the nose) and the tongue, which are crammed into a smaller space where they obstruct airflow through the upper airways. Additionally, a lack of underlying nasal bones causes the nostrils to narrow into small slits instead of large open holes. If you watch these dogs closely, you will see many of them are forced to breath through their mouth and pant, or use their abdominal muscles to force air in and through their narrowed airways during normal breathing.
Vets call this syndrome ‘Brachycephalic Obstructive Airway Syndrome’ or BOAS for short. Four anatomical features of flat faced dogs are commonly recognised to cause BOAS:
Increased breathing effort eventually creates a suction effect in the back of the throat, which causes it to collapse inwards further narrowing the already small airway. This can cause very serious breathing difficulties and tends to get progressively worse over time.
Forced breathing also causes swelling in small nasal cavities and airways, eventually leading to fluid accumulating in the lungs. This can progress to right sided heart failure, as the heart struggles to pump blood around the damaged lungs.
The increased effort to breath can result in vomiting or regurgitation of stomach acid. In severe cases efforts to breath can be so forceful that they can displace part of the stomach into the chest cavity through a hole in the diaphragm during breathing. This is known as a hiatal hernia and requires surgical correction.
Obstructive sleep apnoa occurs when the airway becomes blocked whilst dogs are sleeping, causing them to wake up abruptly. This can occur multiple times in a night for some dogs and severely impact their quality of life.
Try pinching the top of your nose to partially block your nostrils, then breath in and out through your nose only. This is quite unpleasant after a few minutes or less, but many brachycephalic dogs are doing this every minute of every day for their entire lives!
What’s it like to be an active brachycephalic dog? Try running on the spot or jumping up and down for a few minutes, then put a drinking straw in your mouth and breath only through the straw. You’ll probably struggle to breath through the straw and have to quickly remove it to take big gasp of air. Remember brachycephalic dogs don’t have the option to do that!
Snoring, snorting and noisy breathing might seem cute or harmless but it is a sign that a dog is suffering from respiratory disease! Many breeders, owners and even some vets think that these noises are normal for their dog or for the breed, but this is far from the truth. Dogs with breathing problems are at high risk of choking on food, collapsing and heat stroke, and may require major surgery.
Noisy breathing is not cute, it is abnormal. Please #dontignorethesnore!
The flattened skull of brachycephalic dogs causes their eye sockets to become shallow and their eyes to protrude significantly. As a result, the outer surface of the eye is more exposed and is prone to becoming dry and irritated or directly traumatised which can lead to painful ulcers (holes in the sensitive surface of the eyeball). In some dogs, the eye sits so prominently outside of the socket that their eyelids cannot fully close over it, leading to the eye becoming incredibly dry and painful. Many breeds have the additional irritation of exercise skin folds around the eyes and nose, which can rub directly onto the eyes. Finally, as less of the eye is sat within the flattened socket of the head, brachycephalic dogs are far more prone to the eye prolapsing out of its socket. Only minor knocks and bumps can cause this is extreme brachycephalic breeds. The combination of eye problems is called ‘Brachycephalic Ocular Syndrome’ and can lead to constant irritation, pain and eventually blindness.
Dogs can’t sweat like we do, and instead have developed a clever way of losing heat by drawing air rapidly back and forth across the moist surfaces in their mouths. This is why you will see dogs panting in hot weather or when they have been running for a long time. However, panting is only effective when there is a large enough surface area in the mouth proportional to the size of the dog. In brachycephalic dogs, we have shrunk the mouth and the moist tissues within it, without reducing body size in proportion! As a result, in hot weather brachycephalic dogs cannot lose heat fast enough to regulate their temperature effectively. This can make these dogs feel very ill and uncomfortable, and can lead to collapse, heat stroke and death if they are not cooled rapidly and sufficiently!
In breeds such as the Pug and the Bulldog, the skull getting shorter and flatter has resulted in excessive skin covering the face which forms thick folds and wrinkles. The deep crevices between the folds create the perfect warm, moist environment for bacteria and yeast to grow and cause infections. Whilst antibiotics, antibacterial shampoos and pain relief can help, infections often relapse and can become chronic lifelong conditions because the underlying cause is not removed. In cases where the skin folds occlude the eyes and rub on the surface of the eyeball causing irritation, surgery may be necessary to prevent painful eye ulcers developing.
One way in which altering the face and skull of brachycephalic dogs has impacted their health is their reduced intrinsic ability to communicate with other dogs. Dogs use visual communication to signal their intent to others, from bowing down on their front legs to invite playtime, to widening their eyes to show fear and curling their lips to indicate aggression. Pugs and other small brachycephalic breeds with their shortened legs are unable to crouch, French Bulldogs with their stump tails have lost all ability to signal their intention with their tails, and all flat faced breeds struggle to communicate normally with their drastically altered facial conformation. It has been shown that the Cavalier King Charles Spaniel has only one ‘dog-to-dog’ signal out of a possible twenty visual signals used by dogs closer in appearance and genome to the wolf. Dogs whose repertoire of visual signals is restricted are often avoided by other dogs, and can become anxious, isolated and even dog-aggressive due to inadequate socialisation.
Birth problems are very common in brachycephalic breeds due to the mismatch between puppies having large domed heads due to brachycephaly, and mothers having relatively narrow pelvises. This results in very few natural births, with many dogs undergoing serious life-threading caesarian surgery to deliver their puppies. 86% of English Bulldog pregnancies have been found to end in delivery due to caesarean section.
As we bred brachycephalic dogs to have smaller and flatter skulls, their soft tissues failed to reduce in size and so did their teeth! The small squashed face of brachycephalic dog has the same number of teeth as a dog with a normal muzzle, all crowded into a much smaller space. As a result, teeth might stick out at right angles, or grow inwardly towards the roof of the mouth where they cause horrendous pressure sores. This results in food getting stuck between the much reduced space between teeth leading to infection, gum disease and eventual tooth loss. It is also common for brachycephalic dogs to fail to lose their baby teeth as they are crammed so tightly together they remain. In these cases if not surgically removed in time, the permanent teeth may erupt alongside these teeth at uncomfortable angles worsening the overcrowding in the mouth. In worst case scenarios these dogs can struggle to eat, and may need to have many teeth surgically removed just to make their mouths comfortable.
The narrowed airways and increased risk of overheating associated with brachycephalic breeds predisposes them to complications during anaesthesia. The stress from hospitalisation and anaesthetic drugs can cause their already restricted airways to narrow further and increase the risk of life-threatening airway obstruction. This can make all surgery, from neutering and routine procedures, to high-risk airway operations, more dangerous in comparison to dogs with normal skull anatomy.
Brachycephalic dogs suffering from obstructive airway sydrome are prevented from performing normal canine behaviours such as sustained running and exercising due to their respiratory compromise. This forced low-energy lifestyle makes brachycephalic dogs prone to obesity which further aggravates their respiratory disease as well as increasing their risk for a host of other health problems, from heart disease and strokes to arthritis and diabetes.