Published: 12 Jun 2020 | Last Updated: 18 Jun 2020 16:17:57

Breeds with flat faces (brachycephalic) – such as bulldogs, French bulldogs and pugs – are at particular risk of developing heat stroke, the largest study of its kind suggests.

RVC VetCompass research in collaboration with dog welfare scientists at Nottingham Trent University analysed the anonymised clinical records of over 900,000 dogs across the UK. They found that more than 1,200 dogs had received veterinary care for heat stroke during the study, with almost 400 affected in a single year. But this is just the tip of the iceberg as many dogs affected with heat stroke may not even be taken to a veterinary surgery.

The study identified that the following breeds were at most risk (compared to Labrador retrievers): Chow Chow (x17); Bulldog (x14); French Bulldog (x6); Dogue de Bordeaux (x5); Greyhound (x4); Cavalier King Charles Spaniel (x3); Pug (x3); Golden Retriever (x3), Springer Spaniel (x3).

Many of these breeds are flat-faced meaning that they have a ‘brachycephalic’ skull with a shortened head, flat face and short nose. As well as breed, the study identified some other important predictors for heat stroke in dogs, including being above average weight and being over two years old. Dogs that were big for their breed – including both obese dogs and large or muscular dogs –  had almost one and a half times the risk compared to those that were smaller than the breed average.

The study, published in the journal Scientific Reports, showed that heat stroke can have very severe effects in dogs, with one in seven dogs with heat stroke dying as a result of their illness.

Dr Dan O’Neill, co-author and senior lecturer in companion animal epidemiology at The Royal Veterinary College, said: “As the UK moves progressively towards higher average temperatures due to global warming effects, we all need to wake up to the changing health hazards that our dogs will increasingly face. Greater understanding of which breeds, ages and types of dogs are at extra risk of heat-related illness can assist owners to select breeds that are more resistant to heat effects and to plan how best to protect predisposed dog types from their increased risk by, for example, altering times and levels of outdoor activity. Knowledge is power when it comes to protecting our beloved dogs. A core message from this study would be to “stop and think before buying a flat-faced dog.”

This study is part of the ongoing VetCompass research programme at the Royal Veterinary College that aims to improve companion animal welfare and was supported by a Dogs Trust Canine Welfare Grant. For more information, see Dogs Die In Hot Cars.

Full paper freely available open access: http://nature.com/articles/s41598-020-66015-8