Equine obesity is increasing in the UK, according to new research from the Animal Health Trust (AHT) published in the Equine Veterinary Journal.
Pony breeds, particularly UK native breeds, and heavier horses such as draughts and cobs were all significantly more likely to be obese compared to Thoroughbred horses.
The increased risk may be due to these native breeds having adapted to thrive in harsh environments with sparse grazing available.
Charlotte Robin, research assistant at the AHT and lead author of the paper, said: “Native breeds may be genetically better adapted to survive in harsh conditions, having a so-called thrifty genotype, increasing their risk of obesity when maintained in an environment where food is of better quality and more readily available.”
Horses described by their owners as readily being able to gain weight or being “good doers” were more than three times more likely to be obese, compared to those that normally maintained weight.
The research, funded by World Horse Welfare (WHW), also highlighted various links to human obesity.
Charlotte said: “In humans, obesity is associated with poor health status and chronic health conditions including diabetes, hypertension, respiratory disease and arthritis. Similar associations between obesity and adverse health events have been described in equines.”
Similarly in humans, exercise significantly improves insulin sensitivity, and it is thought the same “dose-response” effect is mirrored in horses.
The research highlighted that the risk of obesity was greater in pleasure or non-ridden horses, with pleasure horses being more than twice as likely to be obese and non-ridden horses nearly three times more likely.
Competition animals receive increased exercise at a higher intensity and are fitter than non-competition animals, further reducing the risk of obesity.
WHW’s deputy head of UK support Sam Chubbock said excess weight was one of the greatest challenges facing horse owners.
“That’s why we supported this vital research,” she said. “Being overweight can be just as much, if not more, of a health concern as being underweight.
“In our experience it can take three times longer to get an overweight horse back to optimum condition than it can a thin horse. Moreover, a previously obese horse’s weight will need to be managed for the rest of its life, even after the weight has come off, and they are likely to suffer long-term effects.
“Managing a horse prone to weight gain can be incredibly difficult and this is why our Right Weight project provides practical guidance for owners on how to assess and manage their own horse’s weight.”
One of the most common health conditions linked to equine obesity is laminitis, a painful and debilitating disease affecting the feet.
A new AHT study, in collaboration with the Royal Veterinary College and funded by WHF is aiming to take a closer look at the management factors, which may increase the risk of laminitis in the British equine population.
The study, called Care About Laminitis, will be launched next month and will ask owners of laminitic and non-laminitic horses or ponies to complete monthly online diaries.