Equine Metabolic Syndrome

Equine Metabolic Syndrome (EMS) is the collective name given to various presentations which include Peripheral Cushings, Laminitis and Insulin dysregulation. EMS has emerged over recent years and would appear to be very much on the increase. Whereas laminitis used to be almost exclusively associated with overweight ponies and Cushings symptoms were only ever seen in older individuals as the result of a pituitary tumour, EMS is now presenting in individuals within a wide range of ages and types.

Insulin dysregulation is seen in horses with EMS and those with Cushing's disease, and is associated with obesity. This is similar to type II diabetes in humans where the action of insulin is impaired, despite often elevated concentrations. It is of interest primarily because of its link to laminitis. Horses with EMS will have an increased insulin response after they are given oral sugars, which will cause a subsequent rise in blood insulin levels (hyperinsulinemia). Hyperinsulinemia results in decreased tissue sensitivity to insulin, or insulin resistance, especially by the skeletal muscle, liver and adipose tissue. Tissue insulin resistance maintains blood sugar levels which in turn causes further insulin secretion, which perpetuates the cycle.

There appears to be a strong link between decreased insulin sensitivity in obese animals; however, it is unknown which is the cause and which is the result. When certain tissues that are sensitive to insulin (eg. skeletal muscle) develop triglyceride deposits, cellular functions are altered, one of which is insulin signaling.

Clinical Signs

EMS horses tend to become obese very easily, depositing fat in the crest, shoulders, loin, above the eyes, around the tail head, and the mammary glands or prepuce, even when the rest of the body appears to be in normal condition. Some horses may have regional adiposity, and others may even appear normal weight, so obesity is not a definitive clinical sign of a horse with EMS. Horses will be insulin resistant (IR), and may have hyperinsulinemia, have abnormal blood glucose, or abnormal insulin responses to glucose. IR predisposes the animal to laminitis, and horses with EMS may have had previous episodes in their history.

Other signs suggesting EMS include elevated blood triglyceride levels and leptin levels, hypertension, and reproductive changes in mares - an increased diestrus period, and a lack of anestrus. Horses also occasionally show anaemia and elevated γ-glutamyl transpeptidase (GGT) levels.

A Different Perspective

Most effort seems to be spent on diagnosis and treatment, conventionally, that requires careful dietary control and unlicensed Metformin administration (a human drug for Type II diabetes) that has low bio-availability in horses and little effect on insulin sensitiity at the commonly used dose levels. It is thought that it's main action is to reduce glucose absorption in the digestive tract when given prior to meals, but this is treating symptoms rather than getting to the underlying cause.

Roger has always been convinced that there is a management cause of EMS in order to explain it's emergence and increasing incidence. It would make sense that there is a toxicity involved that is effecting liver function and insulin sensitivity. Until recently, Roger had not discovered the probable cause of EMS but he has now been convinced that the increased use and higher doses of Glyphosate (the prime active ingredient of the weedkiller "RoundUp") is the most likely culprit. For more information see the page on Glyphosate and how it can effect not only horses but humans and other species too.

The good news is that although numbers are still quite low at present, Roger has had some success in treating horses and ponies diagnosed with EMS based on presuming it to be of toxic derivation. With his more recent understanding with regard to the probable role of Glyphosate, Roger is confident that a successful treatment regime can be achieved.

Of course treatment is only one aspect of this. It is crucial in order to maintain health that horses are not subjected to further Glyphosate or other toxicity, or at least as little as possible.

Read more on Glyphosate ...