It is no surprise that weight loss has important health benefits for fat ponies but now there’s proof that conscientious owners really can help reduce the risks posed by obesity.

Clinical studies have already identified that calorie restriction and increased exercise are the mainstays of treatment for EMS but in the field there has been potential for poor owner compliance, which has historically made it difficult to monitor effects of owner-managed weight loss accurately. The new study, published in the Equine Veterinary Journal (EVJ) has shown that owners of ponies with equine metabolic syndrome were able, with veterinary support, to implement highly effective weight loss programmes and thus improve insulin sensitivity and reduce the risk of laminitis.

The study is one of the topics in this month’s EVJ Podcast, aimed at helping vets to help their clients. The other topic on the podcast compares the benefits of oral glucose and sugar tests as effective and convenient ways for vets to monitor insulin sensitivity in the field, further helping home management of weight-related risks. 

Equine metabolic syndrome is a complex condition, defined by clinical consensus as obesity, insulin resistance and an increased susceptibility to laminitis. Insulin resistance is the underlying symptom, ultimately resulting in laminitis.

The study, Treatment of equine metabolic syndrome: a clinical case series, was conducted by vets at the Universities of Liverpool and Edinburgh to determine whether significant weight loss and improvements in insulin sensitivity can be achieved in horses and ponies with EMS, managed by their owners at home under veterinary guidance.

A total of 19 horses and ponies with suspected EMS and/or a history of laminitis were included in the study. They underwent a clinical examination and endocrine testing. Owners were then given individually tailored diet and exercise programmes to follow for between three and six months. They were given daily support from vets throughout the period.

After the treatment, clinical examination and endocrine tests were repeated and results compared to the initial assessment. All but one showed a significant reduction in weight, accompanying reductions in insulin levels and thus reduced susceptibility to laminitis.

Ruth Morgan, co-ordinator of the project, is based at the University of Edinburgh.  Her team used the combined glucose-insulin test to monitor horses in her study. This is a very accurate way to assess insulin function, but it does require intravenous catheter placement and multiple blood samples. As alternatives to help to identify ponies at risk of laminitis and monitor and manage them more effectively at home, vets can also use the in-feed oral glucose and oral sugar tests. These relatively new tests can be used to assess insulin sensitivity, simply by feeding a specified level of glucose or corn syrup and then taking a single blood test. Recent research, also published in Equine Veterinary Journal and discussed in the podcast by Sarah Smith of the Royal Veterinary College, indicates that the two tests agreed in most cases but further research is required to identify the most appropriate test.

Ruth Morgan said: “Our weight loss work shows that if owners are educated, informed and encouraged by their vets they can effectively induce weight loss and improve insulin resistance. We found that the key to compliance is the individual tailoring of a weight loss programme for each horse.”

Sarah Smith said: “Our work will help provide vets and owners with simple and practical methods to assess horses’ insulin function and monitor the impact of diet and exercise programmes. At the moment, we cannot say one oral test is more appropriate than the other, the key thing is to use the same test repeatedly if an individual horse is monitored over time.”

Celia Marr, editor of the EVJ continued: “We know that most owners are keen to do the best for their horses but sometimes they lack the knowledge or facilities to implement a weight loss programme easily. This study has shown how consistent, responsive support from a vet, coupled with innovative individual methods for weight loss can make all the difference.”

Ruth Morgan’s Tips for weight loss

  • Ask your vet for advice before embarking on a weight loss programme
  • Restrict overall intake and take account of everything the horse eats e.g. feed hay at 1.5% of bodyweight, feeding at least twice a day
  • Have forage analysed – you need hay with a low sugar (water soluble carbohydrate, WSC) content.
  • If the WSC is high, soak the hay to reduce water soluble carbohydrate content, but you may need to increase the bulk of the diet to up to 2% bodyweight if the hay is soaked
  • Cut out all treats and additional feeds but do use a high quality balancer
  • As long as the horse is sound, provide daily exercise regularly increasing the horse’s heart rate to 100-150bpm if you can, which will burn calories. This will mean trotting and cantering to induce puffing and sweating rather than just walking.