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  5. What do I need to know about Brachycephalic dogs?

What do I need to know about Brachycephalic dogs?

We know that the human families of brachycephalic, or flat-faced dogs love and cherish these characterful and affectionate animals. These breeds have great personalities and form strong bonds with their owners. Unfortunately, the exaggerated physical features that often initially draw people to these breeds, like their flat faces, cause these animals health and welfare problems. The noticeable breathing noises that these dogs make, like snuffling, snoring and snorting, is a sign that breathing is very difficult and distressing for the dog, and this realisation can be heartbreaking.

Animals with extremely exaggerated physical features may require specialised veterinary care to improve their comfort and quality of life. These pets may also need additional lifelong daily care from their owners. Potential owners should carefully and seriously consider their capacity to provide adequate, often ongoing, care for a brachycephalic pet. This includes considering financial circumstances, having access to a specialist emergency veterinary clinic, likelihood of travel or relocation, and participating in an active or busy lifestyle.

Features of brachycephalic animals

Brachycephalic animals, including dogs and cats, have an exaggerated short and wide skull, and their bottom jaw is disproportionately longer than their upper jaw (commonly known as an ‘undershot’ jaw). These abnormalities are a result of selecting features to comply with pedigree breed standards, where the focus has been on physical traits and appearance rather than on traits that will maintain or improve the health and welfare of the animal.

Brachycephalic dogs can suffer from a range of health and welfare issues including breathing problems, digestive issues, eye diseases, difficulty giving birth, spinal malformations, exercise and heat intolerance, sleeping difficulties, skin and ear diseases, as well as dental disease [1].

Brachycephalic Obstructive Airway Syndrome (BOAS)

Brachycephalic Obstructive Airway Syndrome (BOAS) is a breed related disorder commonly seen in dogs, which results in breathing difficulties and significant compromise to their welfare and quality of life [2]. BOAS is a lifelong and often progressive disorder that affects an animal’s ability to live comfortably and engage in normal animal behaviours. In general, BOAS-affected breeds have and often suffer from unprovoked coughing, sneezing, and snoring. In addition to early onset of respiratory disease, this condition also has negative secondary impacts on an animal’s ability to behave normally including impacts on their breathing, exercising, eating, playing, and sleeping (see ‘Inability to engage in normal behaviours and daily activities due to the constraints relating to BOAS and other physical limitations’ below). Common breeds that are affected by BOAS include the French Bulldog, Pug, British Bulldog, Boston Terrier, and Boxer. See these articles on BOAS and narrowed nostrils for more detail.

BOAS is also thought to increase the health risks associated with air travel for brachycephalic dogs, during which some animals have tragically died. This has resulted in some airlines refusing to accept these animals for air transport or otherwise imposing strict guidelines for airline travel due to the high risk of serious health problems and death.

Brachycephalic Ocular Syndrome

The flattened brachycephalic head shape commonly includes eye sockets that are very shallow, giving a ‘pop eyed’ appearance which may lead to various abnormalities of the eye and related diseases, collectively as Brachycephalic Ocular Syndrome [3]. Breeds such as Pugs, British Bulldogs, and French Bulldogs are predisposed to Brachycephalic Ocular Syndrome.

To help prevent these conditions and minimise pain and discomfort, these dogs may need to undergo multiple surgeries, although some of the conformational conditions cannot be corrected by surgery. Instead, frequent or life-long topical eye medications may be needed, particularly since there is a risk of blindness that can occur long term or if left untreated. See this article for more detail.

Brachy Bug Labelled
Above: A picture of a Pug showing abnormal protruding eyes (A), facial folding (B) which may come into contact with the protruding eyes resulting in irritation, and tear staining of the face (C) which can be a result of abnormal tear production.

Difficulty giving birth

Many brachycephalic dog breeds have substantial difficulty giving birth, due to the puppies’ heads and shoulders being much wider than the mother’s hips and birth canal [4]. The mother may have trouble breathing due to the stress and physical exertion of birthing causing a further risk of a tragic outcome. This can make veterinary assistance necessary, which may include anaesthetising the mother, then surgically removing the puppies (a caesarean section or C-section). These significant health risks and interventions can result in negative impacts on both the mother and pups’ welfare. See this article for more detail.

Brachy English Bulldog
Above: A picture of a British Bulldog showing the breed’s characteristic features including their wide head and shoulders and narrow hips.

Spinal and tail malformations

Some brachycephalic breeds including the British Bulldog, French Bulldog, Pug, and Boston Terrier have a tail malformation, also known as screw tail [56]. A screw tail is a genetic malformation that causes the bony part of the spine forming the tail to have a reduced number of bones (so that it is shortened) and some of the bones fuse together (so that it curls or kinks) [7].

Above: A photo of a French bulldog showing the classic appearance of a the “screw tail” (a shortened and curled/kinked tail) indicated by the red arrow, which is commonly seen in many brachycephalic dog breeds.
Above: A close up photo of the “screw tail” that is associated with spinal abnormalities in some brachycephalic breeds. Photo courtesy of Adjunct Professor Philip Moses – Veterinary Specialist Services, Brisbane, Australia.

Brachycephalic dogs with screw tails also have a high likelihood of having other deformities along the length of their spine, which can cause health conditions such as nerve problems leading to an inability to move normally, pain along the spine, and urinary or faecal incontinence. One study showed that spinal malformations can be found in up to 83% of some brachycephalic breeds, such as British and French Bulldogs [6]. These malformations can potentially cause severe neurological defects which have proven to be very challenging to treat [5]. See this article for more detail.

Figure 1: A 3-D scan of a normal spine with the area circled in green which corresponds to the abnormal area in Figure 2 which is circled in red.
Figure 2: A 3-D scan of an abnormal spine of an affected brachycephalic dog with the area circled in red which corresponds to the normal area in Figure 1 which is circled in green.


In one study, a third of brachycephalic dogs were unable to walk for more than 10 minutes on a 19°C summer day [8]. This inability to exercise normally can severely restrict the walking and play activities these dogs can engage in and share with their owners.

Owners also need to be aware that weight control is extremely important for brachycephalic dogs, as extra weight and obesity can make their breathing problems much worse. Exercise intolerance poses a major challenge for weight management of brachycephalic dogs. As a result, nutritional management is critical to ensure optimum weight. Regular exercise without causing difficulty in breathing is also important, both to help with weight management and to provide opportunities for socialisation and stimulating experiences outdoors.


Some brachycephalic dogs are unable to sleep normally because their narrowed airways become more easily obstructed. Sleep apnoea, which is when breathing stops during sleep, can occur in brachycephalic dogs as they lose conscious control of their muscles and their airways become obstructed while they’re sleeping [9]. Sleep apnoea affects the ability of brachycephalic animals to go into deep sleep for long periods of time, reduces oxygen intake while asleep, and results in them spending more time trying to get to sleep [9]. The increased difficulty of breathing during normal daily activities as well as during the night whilst trying to sleep ultimately leads to substantial levels of undue distress and anxiety in dogs affected with BOAS [10]. Brachycephalic dogs are regularly seen waking up whilst asleep, sleeping while sitting up or with their chin elevated, or sleeping with a toy in their mouth so that their airways remain open to compensate for any obstructions [8].


Brachycephalic dogs have the same number of teeth as all other dog breeds. However, dental and eating complications commonly arise as a result of their teeth growing into a much more narrowed set of gums. This overcrowding of their teeth can lead to an undershot jaw, or abnormally projected bottom jaw, as well as increase their risk of early onset dental disease [2]. Dental disease can often be painful, particularly when dogs are eating soft or hard foods. Although some brachycephalic dog owners feel that these small mouths are adorable, the unfortunate consequences of overcrowded teeth and a misaligned jawline can result in an inability of affected dogs to eat without difficulty. The negative impacts of not being able to eat can further lead to other serious health risks in these dog breeds. See “Dental disease” below for more detail.

Ear Infections

An additional consequence of brachycephalic traits in dogs is a predisposition to reoccurring ear infections. Particularly prevalent in French bulldogs, brachycephalic dogs often have very narrow ear canals that do not allow for adequate air flow which creates the ideal warmth and moisture needed for bacteria to flourish [11]. Ongoing ear infections are generally difficult to treat, can be very painful, and can cause a lot of stress to dogs and their owners. In some cases, these types of infections can eventually progress to deeper parts of the ear and ultimately lead to hearing loss.

Skin Disease

Like ear infections, selection for brachycephalic traits has also resulted in these dogs having multiple deep skin folds over various parts of their body, commonly around the face and base of the tail [1]. Consequently, these skin folds create a warm and moist environment for fungi and bacteria to thrive causing pain and discomfort. Surgical correction may help to remove the skin folds but, in most cases, bacterial and fungal treatments are required frequently and long term. Continuous infection of the skin can lead to constant itching, self-trauma, and a poor quality of life.

Dental Disease

Brachycephalic dogs may also be predisposed to dental disease, particularly at a younger age than most other breeds. They have a normal number of teeth that must fit into a space that is comparatively smaller than in other breeds, as their flattened face reduces the gum area within their mouth. This causes overcrowding of the teeth which increases the risk of food and dirt becoming trapped between their teeth [2]. This leads to an overgrowth of bacteria in the mouth causing inflammation and infection of the gums around the teeth. To avoid this, owners can provide at-home dental care or in more severe cases, dental surgery by a veterinarian may be required, including tooth extractions to reduce overcrowding in the mouth to try and prevent bacterial overgrowth. See this article for more detail.

Inability to engage in normal behaviours and daily activities due to the constraints relating to BOAS and other physical limitations

The consequences of compromised airways from BOAS in brachycephalic dogs seriously affect their ability to engage in normal dog behaviours. In addition to their impaired ability to breathe naturally, these dogs often have other physical constraints (resulting from BOAS and other conditions such as hemivertebrae) restrict brachycephalic dogs from being able to play, exercise, sleep, and eat normally.

Brachycephalic dogs have shortened skulls compared with other dogs [1]. Dogs who have shortened skulls often have very prominent facial skin folds and these can affect the dog’s ability to communicate with other dogs, for example it is difficult for them to lift his/her lips to signal fear and aggression to other dogs [1]. A lack of a ‘normal’ dog tail can also affect dogs’ ability to communicate with other dogs (and people) [12], this could disadvantage brachycephalic dogs who have very short and/or curled tails.

These dogs often have crowded teeth (see Dental Disease) and this may compromise the dog’s ability to chew. This is a normal canine behaviour and has been identified as a mechanism dogs use to cope with stress [1].

More information

RSPCA Australia and the Australian Veterinary Association are raising awareness to try to change how purebred dogs are selected and bred in Australia. Current and potential owners can play a vital role in helping to improve the welfare and lives of brachycephalic breeds. For more information or to get involved, visit the following websites: Love is Blind, Australian Veterinary Association. See also: American College of Veterinary Surgeons, International Cat Care, Universities Federation for Animal Welfare and UPEI Canine Inherited Disorders Database.


[1] Fawcett A et al (2018) Consequences and management of canine brachycephaly in veterinary practice: perspectives from Australian veterinarians and veterinary specialists. Animals 9 (1).

[2] Ekenstedt KJ et al (2020) Canine Brachycephaly: Anatomy, Pathology, Genetics and Welfare. Journal of comparative pathology 176: 109-115.

[3] Universities Federation for Animal Welfare (2011) Brachycephalic Ocular Syndrome in Pugs https://www.ufaw.org.uk/dogs/pug-brachycephalic-ocular-syndrome (accessed on June 23, 2021)

[4] Universities Federation for Animal Welfare (2011) Dystocia due to Foetal-Pelvic Disproportion in English bulldogs https://www.ufaw.org.uk/dogs/english-bulldog-dystocia (accessed on June 23, 2021)

[5] Gutierrez‐Quintana R, De Decker S (2021) Tail end of the brachycephalic problem: diagnostic and treatment options for spinal malformations. In Practice 43(3): 124-134.

[6] Lackmann F et al (2021) Epidemiological study of congenital malformations of the vertebral column in French bulldogs, English bulldogs and Pugs. Veterinary Record, 22 May 2021: e509.

[7] Mansour TA, Lucot K, Konopelski SE et al (2018) Whole genome variant association across 100 dogs identifies a frame shift mutation in DISHEVELLED 2 which contributes to Robinow-like syndrome in Bulldogs and related screw tail dog breeds. PLoS genetics 14(12): p.e1007850.

[8] Roedler FS et al (2013) How does severe brachycephaly affect dog’s lives? Results of a structured preoperative owner questionnaire. The Veterinary Journal 198(3): 606-610.

[9] Hendricks JC et al (1987) The English bulldog: a natural model of sleep-disordered breathing. Journal of Applied physiology 63(4): 1344-1350.

[10] Quain A et al (2021) Ethical Challenges of Treating Brachycephalic Dogs in Health and Welfare of Brachycephalic (Flat-faced) Companion Animals; Packer, RM., O’Neill, DG. Eds.; CRC Press: Florida; pp. 41-51. ISBN: 978-0-429-26323-1

[11] O’Neill DG et al (2021) French bulldogs differ to other dogs in the UK in propensity for many common disorders: a VetCompass study. Canine Medicine and Genetics 8(13).

[12] Dale S et al (2014). Decoding your dog : the ultimate experts explain common dog behaviors and reveal how to prevent or change unwanted ones. Boston: Houghton Mifflin Harcourt.

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Updated on May 16, 2022
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