Equine metabolic syndrome is linked to the development of laminitis – also known as founder – which is a painful condition of the hoof that can lead to euthanasia if severe.
The key features of this syndrome are insulin dysregulation (changes to insulin metabolism) and the development of obesity, as well as alterations to the levels of certain fat-associated hormones.
According to Dr Nick Bamford there are some similarities with the Metabolic Syndrome described in humans in which obese people are predisposed to type II diabetes and cardiovascular disease.
“With a current lack of effective treatments for laminitis, attention is largely focussed on preventative measures to halt the onset of this debilitating disease,” Dr Bamford said. “The aim of management is to both improve insulin sensitivity and promote weight loss in affected horses.”
The study conducted by University of Melbourne researchers in conjunction with the Waltham Centre for Pet Nutrition investigated whether low-intensity exercise when combined with dietary restriction improved outcomes for obese horses.
The study included 24 obese horses and ponies which were randomly divided into two groups; ‘restricted diet only’ or ‘restricted diet plus exercise’.
They were fed the same diet of restricted hay (with no access to pasture), a small amount of lucerne chaff and soya bean meal, and a vitamin and mineral supplement.
The exercise program was designed after feedback from horse owners to help ensure it could be implemented relatively easily in the real world, consisting of 15 minutes of brisk trotting on a horse-walker, with five minutes of walking either side, five days per week for 12 weeks.
The study was able to demonstrate an additional benefit of low-intensity exercise over dietary (calorie) restriction alone.
“We always suspected that exercise was an important part of managing obese horses who were predisposed to laminitis, but we needed evidence to demonstrate this, especially whether a practical routine of low-intensity exercise is beneficial,” Dr Bamford said.
“For many owners, it can be impractical for them to regularly exercise their horses. What this study provides is the evidence that can hopefully serve as motivation for owners to commit to undertaking regular exercise for affected horses.”
Dr Bamford has worked with clients to implement the low intensity exercise strategy by using either a horse-walker or by lunging, with positive results.
Although diet and exercise will help most horses with equine metabolic syndrome, in more severe cases there might be a limit to how much benefit these strategies alone can provide.
There are medications that can be used to aid in the treatment of equine metabolic syndrome, and although they cannot replace diet and exercise, medications can be part of an overall management program in severe cases.
While equine metabolic syndrome is highly unlikely to occur in racing thoroughbreds, there is still relevance of this work to the thoroughbred industry in terms of the management of retired horses and broodmares.
This is especially true if retired horses are overly sedentary and become obese while consuming lush pasture or diets that are high in sugars, which can lead to changes in their insulin metabolism and predispose them to laminitis.
Dr Bamford said that owners and stud managers who had introduced exercise into their management programs for obese horses had seen benefits that made the extra work worth the effort.
Dr Bamford said they had planned to expand their research into a larger field study but that had to be put on hold due to COVID-19.
“We plan to continue this research in the future and expand the project into a broader population of horses and ponies. We don’t have a timeline, but we hope to resume everything that we wanted to do over the past two years.”
