Equine metabolic syndrome is a widely recognised collection of risk factors including insulin deregulation and obesity which may lead to the development of endocrinopathic laminitis.

These horses are usually described as “easy keepers” by their owners and often have fat deposits in the crest of the neck, over the tail head, above the eyes, behind the shoulders, and in the sheath of male horses. They may be obese overall or simply have regional fat deposition as previously described. Although obesity is a common finding, it is important to note that not all horses with EMS are obese.

What is Insulin Dysregulation? 

IR is defined as the failure of tissues to respond normally to the hormone, insulin. Insulin is one of the hormones responsible for maintaining normal blood glucose levels. Insulin is released by the pancreas when blood glucose levels are high, stimulating the body’s cells to take up glucose from the blood stream.


Diagnosing Insulin Dysregulation

Whilst there are a number of tests which have been described in the recent 2019 ECVIM Consensus paper on Equine Metabolic Syndrome, we routinely perform the ‘In-feed Oral Glucose Test’. This test is simple and easy to perform on your property and only requires a single visit. It essentially tests the body’s response to oral glucose and closely mimics what happens following a meal.

Other tests which are available test the response to intravenous glucose, insulin or both and these focus on the tissue insulin sensitivity. These tests are more suited to be performed in a hospital-setting.

How is EMS different from PPID (Cushings Disease)?

Horses with EMS do not necessarily have a dysfunction of the pituitary gland, which is the hallmark of Equine Cushings Disease. It is possible that a horse with PPID could also have insulin dysregulation. Your horse should also be tested for PPID if they are over 15yo.

For more on how to manage your horse with EMS go here.