Obese Horses & Equine Metabolic Syndrome

Equine Metabolic Syndrome (EMS) is a name used to describe a range of symptoms, including insulin resistance or dysregulation, obesity and recurrent laminitis.

Research in humans in the 1990s demonstrated that adipose (fat) tissue isn’t just an inert store – it can actually develop the ability to secrete hormones. Hormones are chemical messengers in the body and it is known that adipokines (hormones produced by the adipose tissue) can affect immune function, inflammation, tumour development and glucose regulation. Keeping blood glucose levels within normal ranges involves a number of hormones, one of which is insulin. If the function of insulin is compromised, it is referred to as insulin resistance.

Insulin facilitates the removal of glucose from the blood, so insulin resistance can result in blood sugar levels remaining elevated despite more and more insulin being produced. It is thought that over-exposure to insulin and glucose can damage the cells lining the blood vessels (endothelial cells). As these are responsible for the constriction and dilation of blood vessels, the link between insulin resistance and obese horses and laminitis becomes apparent. This is why balanced and nutritious horse feed is essential to help avoid these types of equine health issues.

How To Help Your Overweight Horse

Nutritional Management

●        As obesity worsens insulin resistance, the primary aim is to encourage weight loss and maintain the horse at an ideal bodyweight

●        Grazing should initially be eliminated until bodyweight is normal and recurrent laminitis under control

●        Total feed and forage intake should initially be restricted to 1.5% of the horse’s bodyweight on a dry matter basis, but dropped to 1.25% of bodyweight if the horse is resistant to weight loss

●        Ideally, supplementary feed and forage should supply less than 12% NSC dry matter – this is the sum of the water soluble carbohydrate and starch added together

●        Although soaking hay encourages loss of water soluble carbohydrate, it should not be relied upon to make high NSC hay ‘safe’ because results are highly variable

●        Providing a balanced diet with respect to vitamins and minerals is especially important, as EMS horses are in an inflammatory state and many vitamins and minerals are important antioxidants

●        Longer term grazing may be allowed, but should be restricted by area or with use of a grazing muzzle to manage NSC intake and bodyweight

Benefits Of Exercise

Although it can often seem that however much work you do with your horse it doesn’t seem to lose weight, it is important to keep doing it. Double check that you are sufficiently reducing your horse’s calorie intake through dietary restriction as exercise alone will not result in sufficient weight loss.

It is also important to consider that, even if the horse isn’t losing weight, exercise might help to maintain sensitivity to insulin, as has been found to be the case in humans. Therefore, even if the horse isn’t losing weight, exercise could help to avoid insulin resistance and laminitis.