Selective breeding could reduce BOAS rates, study suggests
Both respiratory function and nostril size were considered 'moderately inheritable'.
A new study has investigated how breeding programs could reduce rates of the breathing disorder brachycephalic obstructive airway syndrome (BOAS).
Researchers from the Royal Kennel Club suggest that selective breeding could alter heritable traits relating to the condition, including respiratory health and nostril size.
The new study saw researchers seek to estimate the heritability of BOAS in bulldogs, French bulldogs and pugs. To do so, the researchers examined respiratory health and breeding records from the Royal Kennel Club for more than 4,000 dogs.
The analysis revealed that both respiratory function and nostril size were moderately inheritable.
Based on these records, researchers calculated that 21-49 per cent of variability in dog’s respiratory function was attributable to genetics. Similarly, 31-39 per cent of variability in nostril size was linked with genetics.
Since poor respiratory function, narrow nostrils and high bodyweight tended to co-occur, the researchers now suggest that respiratory health could be improved by avoiding breeding dogs with such traits.
The French bulldog was found to have the lowest rates of BOAS, with 15.6 per cent of tested dogs diagnosed with the condition. This was compared to 18.9 per cent of bulldogs and 19.8 per cent of pugs.
It has been suggested that the reason these statistics are lower than predicted is due to the screening process for BOAS. According to researchers, flat-faced dogs are currently only screened for BOAS if they are showing symptoms of the condition.
The study was also based on samples 5-10 times bigger than earlier reference values, and researchers suggest that health management improvements may have been made since predictions were made.
Dr Joanna Ilska, a geneticist and lead author of the paper, said: “Our findings provide clear evidence that respiratory health in these breeds is influenced by genetic differences between dogs, and importantly, that improvement is achievable through selective breeding.
“By using objective tools like the Respiratory Function Grading Scheme, breeders can make more informed decisions that prioritize health, helping to reduce the prevalence of BOAS over time.”
The RSPCA has described the study as a ‘sobering reminder’ of the health issues faced by flat-faced dogs. The charity states that nearly one in six dogs in the UK are estimated to be brachycephalic, which it says leads to poor welfare and a reduced life expectancy.
It has criticised dog breeders for breeding dogs with BOAS, with short and flat faces posing a wide range of welfare issues. However it has also urged the Royal Kennel Club to act on its findings.
Samantha Gaines, head of companion animals at the RSPCA, said: “We urge the Royal Kennel Club to listen to their own research, not only implementing the changes it highlights are needed - but to go beyond this by committing to more moderate breed standards for these dogs, and prioritising health and welfare in their judging process.
“Health, happiness and the ability to function as a dog is always more important than appearance.”
The Royal Kennel Club declined to comment. The full study can be found here.
Image © Mutlu Project/Shutterstock
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