Page 28 - Eclipse - RVC Alumni Magazine - Autumn 2020

Flat-faced dogs and heatstroke risks
The largest study in the UK to date on the subject indicates that brachycephalic (flat-faced) breeds are particularly at risk of developing heatstroke.
RVC and Nottingham Trent University researchers analysed the anonymised veterinary clinical records of more than 900,000 dogs across the UK. Over 1,200 of them had received veterinary care for heatstroke during the study, with almost 400 affected in a single year. This is the tip of the iceberg as many dogs with heatstroke may not be taken to a veterinary surgery.
The study is part of the ongoing RVC VetCompass research programme that aims to improve companion animal welfare. It was supported by a Dogs Trust Canine Welfare Grant.
Many of the breeds that were at increased risk had a ‘brachycephalic’ skull, with a shortened head, flat face and short nose. The Labrador retriever – traditionally the most popular UK dog – was used as the ‘base’ comparison
breed to identify breeds at most risk. The bulldog, an extreme flat-faced breed, was 14 times more likely to develop heatstroke, whilst flat-faced dogs in general were twice as likely.
The study identified that the following breeds were most at risk: 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).
Emily Hall, lead researcher and a vet at Nottingham Trent University’s School
of Animal, Rural and Environmental Sciences, said: “It’s likely that brachycephalic dogs overheat due to their intrinsically ineffective cooling mechanisms. Dogs pant to cool down – without a nose, panting is simply less effective. In fact, brachycephalic dogs may even generate more heat simply gasping to breathe than they lose by panting.”
The researchers are concerned that the increasing popularity of brachycephalic breeds combined with climate change
will result in even more dogs suffering from potentially fatal heatstrokes over time. Consequently, veterinary teams should weigh up potential risk of heatstroke when advising owners on breed selection.
Dr Dan O’Neill, co-author and Senior Lecturer in Companion Animal Epidemiology at the RVC, 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.”
The study, published in Scientific Reports, is freely available open access at: rvc.uk.com/nature-heatstroke
Photo by Emily Hall Photo by Anne Carter
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