Equine Metabolic Syndrome

One of the hormonal causes of laminitis

What is Equine Metabolic Syndrome (EMS)?

EMS is a collection of risk factors associated with an increased level of insulin in a horse's bloodstream, which in turn increases the risk of that horse developing laminitis. These risk factors include (amongst other things) a horse being overweight, a diet high in sugar, and genetic factors that affect the metabolism. All horses with EMS will have higher than normal levels of insulin in their bloodstream, and will therefore be at a high risk for laminitis.

What is the link between EMS and laminitis?

High levels of insulin in the bloodstream will cause laminitis. All horses with EMS have high blood insulin levels: when the amount of insulin tips over a critical level (either because of the underlying EMS or because a horse with EMS has consumed a sugary meal such as lush pasture), it will always cause laminitis.

How is EMS diagnosed?

Your vet can diagnose EMS by taking two blood samples, one before and one after a sugary meal, and comparing the blood insulin levels in the two samples. In addition to determining whether your horse has EMS, this test can also be used to determine your horse's laminitic risk. This is especially useful if you have implemented diet, exercise or management changes to try to reduce your horse's laminitis risk as you can measure the impact that the changes you have made have had on your horse's blood insulin levels.

Can EMS be treated?

The best way to manage EMS is by managing your horse's diet and exercise so that they are a Body Fat Score of 3. Your vet can advise you on the most appropriate management plan to achieve this.

The simplest and most common test for Equine Cushing’s disease is the basal ACTH test.

To perform this test your vet will take a blood sample from your horse and send it to a laboratory that will measure the levels of a hormone called ACTH. The results of the test will then be compared to reference ranges (which change with the seasons) to confirm the presence or absence of Equine Cushing’s disease.

The measurement of serum insulin and glucose is often recommended alongside the basal ACTH test: These tests help to differentiate Equine Cushing’s disease from Equine Metabolic Syndrome (EMS) (another common hormonal cause of laminitis), and also act as an indicator of laminitis risk.

We are providing complimentary ACTH tests to horse owners who suspect their horse may have Equine Cushing’s disease. Simply generate a voucher code by clicking on the Free Test button on this page, and book a visit from your vet to find out whether your vet agrees that this test is appropriate for your horse.