Equine Metabolic Syndrome (EMS): Is it just another label?

EMS or just an incredibly good doer?

An increasing number of horse owners are contacting me for advice regarding Equine Metabolic Syndrome (EMS); a condition which seems widely open to confusion or misinterpretation. So, what is EMS and what does it or should really mean when it comes to feeding our horses?

The term EMS was first adopted in 2002 after some similarities were drawn between horses and the human ‘metabolic syndrome’. In humans, metabolic syndrome is a set of diagnostic criteria that identifies individuals at high risk of disease associated with Insulin Resistance, primarily type 2 diabetes and cardiovascular disease. In horses, EMS is defined as the collective presentation of 1) insulin resistance 2) obesity or regional adiposity (fat) 3) previous or current laminitis. However since first adopted, the term EMS and the criteria for its diagnosis has often caused confusion, which may explain why it seems open to overuse and misinterpretation. There seems to be some agreement that this syndrome has yet to be rigorously defined and that currently, there is no widely accepted definition or set of clinical diagnostic criteria.

EMS is not a disease and is considerably different to the human metabolic syndrome. Despite popular belief diabetes in horses is extremely rare and is likely that there have only been a handful of genuine cases to date. Horses and ponies that have not had, or that are not currently suffering from laminitis, do not fit in with the current criteria for EMS and therefore should not be described as such. In addition, not all laminitics have EMS and this syndrome should not be automatically used as an ‘excuse’ or ‘explanation’ for obesity. There is a concern amongst some that overuse of the term EMS may mean that the true cause or risks of obesity and laminitis could be overlooked. EMS cannot be confirmed without comprehensive veterinary diagnosis and more research into this area is still required. In fact, some nutritionists question whether the term EMS should be used at all at this stage; feeling that the limited research and confusion surrounding this ‘syndrome’ may lead to excessively restrictive or liberal management depending on whether or not EMS is ‘diagnosed’ when in fact, focus should be on identifying and managing the risk factors associated with laminitis.

Nutritional management of EMS, as with any laminitis prone animal should focus on:

·         Providing a diet low in non-structural carbohydrate (NSC – starch, sugar and fructan)

·         Restricting or possibly removing grazing

·         Feeding soaked hay (12-16 hours & ideally in tepid water) or a low calorie hay replacer approved by The Laminitis Trust. Alternatively, consider having your forage analysed

·         Managing weight – aim for a body condition score of 5 out of 9 and remember that it is normal and perfectly healthy for ponies/ natives to lose some weight over the winter before the arrival of better grass in the spring

·         Maintaining regular exercise programme

·         Providing a balanced diet, including suitable levels of vitamins, minerals and quality protein – a feed balancer is the ideal way to provide a balanced diet without excess calories

·         Providing enough fibre – do not restrict forage to less than 1.5% of bodyweight (7.5kg per day for a 500kg horse) unless under veterinary supervision

Laminitis is a serious condition, the risk or occurrence of which should certainly not be taken lightly. However, is simply being able to understand, identify and manage the risk factors associated with laminitis more important and potentially safer than imposing a label of EMS? Some would agree so.