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Equine Metabolic Syndrome

Equine Metabolic Syndrome

Equine Metabolic Syndrome (EMS) is a hormonal disorder that affects horse and ponies, and it is similar to Type 2 diabetes in humans.  It usually occurs in equines between the ages of five and 15 years. It is also a common syndrome that can be managed.


Signs to Look Out For

EMS is characterised by three main signs:

  • Insulin resistance. Your equine will have reduced sensitivity to the insulin they produce and will have trouble controlling their blood sugar levels as a result;

  • Obesity/abnormal fat distribution. EMS is usually seen in horses and ponies that are overweight. When they develop EMS, it can lead to abnormal fat pads and fat distribution over their bodies. Most commonly seen signs are a cresty neck, fat pads behind the shoulders and fat filled eye sockets;

  • Laminitis. Often the first clinical symptom of EMS is an unexpected bout of laminitis. These laminitic attacks often become repetitive. Please go to our laminitis section for more details on laminitis signs.


Other signs seen as the disease becomes chronic include:

  • Difficulty losing weight;

  • Increased drinking;

  • Increased urination;

  • Lethargy;

  • Possible infertility in mares.



EMS is usually caused by certain management practices such as feeding a high-calorific diet to relatively inactive horses and allowing the horse to become obese or overweight.

Bad management practices that can predispose a horse to EMS are usually significant in their impact during the first 10 years of the horse’s life, but the actual syndrome can develop at any point after a horse reaches maturity.

Some breeds are more predisposed to EMS. These include miniature horses, donkeys, ponies, Paso Finos and Morgans.


EMS can be reversed. However, it may take a long time, so advice and support need to be sought.

The main objective of treatment is to reduce the horse’s weight, which in turn will improve insulin sensitivity. The calorie intake will need to be reduced and physical exercise increased. This needs to be done carefully, especially if the horse has been suffering from laminitis, so a vet, a professional coach and equine nutritionist should be able to help.

There are various medications and supplements to help with EMS, but speak to your vet about what would be best to prescribe for your horse.



The best prevention for your horse is to keep them at a healthy weight. This can be done in several ways:

  • Regularly monitor their weight;

  • Don’t over feed them;

  • Don’t over rug;

  • Restrict grazing;

  • Exercise.

It is a good idea to get acquainted with an equine body conditioning scoring chart so that you can keep a regular check on how your horse is doing.  We like the one found here.


How to Calculate Your Horse’s Weight

There are four general methods used to gauge the weight of your horse. Some are more accurate than others, but all should give you a good idea.

  • Use livestock scales. This is obviously the most accurate way of weighing your horse. Sometimes feed companies have these as well as farms.

  • Weight tape. This tape is designed to measure your horse’s weight. First, place the tape just behind the withers and let it drape down and under the body where the girth usually sits. Once it is in place a weight measurement can be read from the tape.

  • Online calculator. For this, you will need to take a measurement of your horse’s girth area and the length. Once inputted into the calculator, a weight will be given. There are many such calculators to choose from online, but we think Hygain’s is one of the most user-friendly.

  • Look at them. While beauty is in the eye of beholder, weight can be too, so study your horse and then compare what you see to a Fat Score Chart. We particularly like the chart that Dengie feeds has on its website:


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