Equine Metabolic Syndrome (EMS) is being diagnosed in record numbers with the median age of diagnosed horses a shockingly young 15 years old. EMS is a condition of the domestic horse and can include obesity, insulin resistance (IR), diabetes (high blood sugar) and metabolic hormone imbalances. It is triggered by the over-feeding of sugars and starches, usually combined with a lack of exercise and/or stress.

EMS often affects the at-risk ‘easy keeping’ breeds including ponies, minis, Fjords, Icelandics, Arabs, Mustangs, Morgans, draft horses and gaited horses. ‘Easy keepers’ are easy because their ancestry and metabolism is adapted for survival in harsh, low-nutrient environments rather than lush sugar-laden pastures with sweet feed for dessert. The over-weight horse standing knee-deep in a lush grass field with no reason to walk or run, other than to graze and get to the water trough is a classic image. Metabolic syndrome is, however, also seen now in recreational horses and some performance horses.

Here’s how it begins:

Normal Sugar Metabolism

When a horse ingests any kind of sugar or starch from grass, grain or hay, it is absorbed from the small intestine into the blood. The sugar in ‘sweet’ food such as grass or grain enters the bloodstream very rapidly compared to the slow absorption of sugars in high-fibre feeds such as beet pulp or coarse hay. This rate of absorption is known as the Glycemic index.

Once it enters the bloodstream, sugar must find its way into the liver and muscle cells where it is either burned for immediate energy, or stored as glycogen and converted back into sugars as required later.

In healthy animals, the transport of sugars into the cells is accomplished with insulin, a hormone produced by the pancreas.

Insulin controls blood sugar levels by attaching itself to specific receptors in the liver and muscle cells, thereby allowing glucose to pass from the blood into the tissues.

The Mechanics of Insulin Resistance

Over time, with a high-sugar, low-fibre diet, these cell receptors can decrease in number and/or become non responsive to the increasingly high insulin levels, at which point, they can no longer open – the receptors have become resistant to the effects of insulin. It is likely that the receptors are not damaged, but are acting defensively to protect the muscle and liver tissue from sugar overload.

With nowhere else to go, these sugars must convert to fat – via the liver – and the easy keeping ‘sugar hound’ becomes very efficient at storing excess blood glucose as fat, which appears in the form of a crested neck, fat pads (eyes, shoulders, and hindquarters) and pot bellies. These fat pads are actually a sign of an overloaded ‘fatty liver’ that pops out fat globules.

The IR horse can have a ravenous appetite – they don’t feel satisfied no matter how much they eat. Surges of insulin trigger pangs of hunger by causing blood sugar to rise and fall erratically.

Diabetes Is Next

Once the fat stores become saturated, the blood sugar levels rise (because the blood sugar can no longer go anywhere); the pancreas can no longer produce enough insulin and the insulin levels drop from an insulin resistant high to a hormonal low. This condition of high blood glucose and insulin deficiency is known as diabetes mellitus, or Type II diabetes.

The diabetic horse exhibits signs of excess thirst, frequent urination, excessive hunger, fatigue and/or depression. An advanced metabolic horse or pony can actually lose weight at this point, since they are no longer able to use glucose as a source of energy; instead they must burn fat and muscle in order to fuel vital body functions. This is as seen as the “skinny diabetic.”

Identifying Equine Metabolic Syndrome

The development of equine metabolic syndrome is usually a slow process as the years of an unnatural lifestyle gradually progress. This development may not be apparent until the early signs or symptoms of EMS begin to appear including weight gain, fat pads, excessive appetite, thirst, fatigue and/or laziness. Sore hooves are also common, but some horses can be metabolic without ever showing signs of tender-footedness.

While lab tests are available to test insulin, ACTH and other hormone levels, they are not always conclusive – endocrine hormones are secreted into the blood in ‘bursts’ rather than in a steady flow, making them difficult to track. Rather than wait for a definitive diagnosis or for clinical signs to appear, it is more prudent to implement prevention strategies as the standard in all horse-keeping practices – no matter the breed or the discipline.

Preventing Equine Metabolic Syndrome

Aside from the at-risk breeds, the biggest risk factors that predispose any horse to equine metabolic syndrome are diet, lack of exercise and/or stress.

  • Unlimited grazing on lush grass and/or the regular feeding of grains are the two most common dietary faults in the barn. Contrary to popular opinion, horses do not require a high-starch or high-sugar diet (or highprotein for that matter) to maintain weight or energy levels.
  • Horses use fibre for energy; the intestinal tract of a horse is evolved to digest high fibre forage, which is typically low in sugars. Fibre is fermented in the cecum by billions of strains of friendly bacteria, known as probiotics. This fermentation process produces volatile fatty acids, which are used at the cellular level for energy. Once the dietary starch-fibre ratio becomes unbalanced, so will the horse’s energy and metabolism.
  • Lack of exercise further contributes to faulty metabolism. Exercise is critical to stimulate the movement of feed through the intestines, improve digestion, increase circulation, maintain optimum metabolic rates, prevent obesity, regulate blood sugar levels and decrease stress.There are a lot of fun ways to exercise horses other than riding – ponying, handwalking, practicing ground work or playing liberty games in the arena with one of more of the herd are not only physically beneficial, but help to engage the horses’ minds and give them variety in their daily routine. Exercise your horses at least twice per week.
  • Stress exacerbates blood sugar imbalances by elevating cortisol levels. As we now know, cortisol is a major contributor to EMS, poor immunity and laminitis. Common causes of stress in the barnyard are infrequent feedings, physical pain, over-training, confinement, isolation (remember horses are social herd animals), lack of companionship, herd dynamics, boredom, neglect and emotional distress.

Dietary Strategies

First and foremost in treating equine metabolic syndrome, the diet must be changed. Supplements and natural remedies will be virtually useless if the diet is not appropriate.

  • Restrict all grass grazing.
  • Feed low-sugar, high-fibre hay only. Either do a hay analysis or soak the hay up to one hour before feeding (this is a temporary measure). Change hay types often until the inflammation decreases naturally.
  • Eliminate all alfalfa.
  • Eliminate all grains including oats, barley, corn, C.O.B. (a combination feed of corn, oats and barley), sweet feed, extruded feeds, complete feeds or any other feeds with added sweeteners.
  • Use slow feeders that enable the horse to eat small amounts of hay all day long thus alleviating digestive problems, blood sugar spikes, boredom and stress.
  • Increase fibre intake by feeding coarse hay, soaked beet pulp and/or soaked soybean hulls. Fibre reduces appetite, regulates blood sugar and increases digestive efficiency.
  • Avoid over-using antibiotics, non-steroidal anti-inflammatories, glucosamine and chemical dewormers, all of which either alter the colonic eco-system, damage the intestinal mucosa, or elevate blood sugar.
  • Exercise your horses and always give them freedom to move. (Never stall a metabolic or laminitic horse).

Natural Remedies

The following remedies can be very beneficial. Note, however, that it can be difficult to determine the exact duration that horses should remain on certain remedies or supplements, as each horse has a unique response to any health program.

  • Give a good quality probiotic once daily, for one to two months, to replenish friendly bacteria in the hindgut. To ensure potency, probiotics should be kept refrigerated before and after purchasing, and contain at least 50,000 CFUs.
  • Use a colon cleanser such as psyllium seed (not the husk), slippery elm and/or aloe vera to remove the overload of mal-digested feed material, bacteria, toxins and acids. Give daily, for six to eight weeks, and follow the dosage instructions on the label.
  • Feed Vitamin B6 – 500 to 900 mg (depending on weight) – daily, for up to four months. B6 will regulate blood sugar levels, support the liver and strengthen the hormone system including the pancreas, pituitary and thyroid.
  • In the presence of Cushing’s symptoms and/or fatigue, feed Siberian ginseng powder, two to three tablespoons daily, for up to four months, to strengthen the adrenal glands; support the pituitary gland; stabilize blood sugar; relieve stress, fatigue and burn-out; and build vitality, energy and stamina.
  • For laminitis and inflammation, feed two to three tablespoons of yucca root powder for as long as required to relieve discomfort.


Leaky Gut (Cecal Acidosis)
Sugars and starches are normally digested with enzymes in the small intestine. When large amounts of sugars and starches are ingested, the small intestine cannot digest them all at once, thus the digestive load is forced back into the cecum in the hindgut for fermentation. The excess fermentation of sugars causes abnormal levels of gas (often causing colic), heat and acids. These destructive lactic acids destroy beneficial bacteria (probiotics), but are favoured by harmful strains of bacteria such as Salmonella, Streptococcus, and E. Coli as well as yeast cells.

These bacteria then produce a variety of different toxins that are very damaging to the colon walls. This cocktail combination of gas, heat, acids and toxins is known as cecal acidosis, a condition that not only permanently disrupts the natural balance of microflora by killing off beneficial bacteria and encouraging the growth of unfriendly bacteria, but damages the intestinal lining of the colon making it abnormally permeable.

Known as “leaky gut syndrome” the damaged colon allows the migration of bacteria, yeast, acids, and related toxins to leak across the membranes, out of the colon and into the general body systems affecting the liver, kidneys, heart, muscles, immunity, and the ever sensitive laminellar hoof tissue. Leaky Gut is a major cause of laminitis as well as arthritis, skin conditions, digestive disorders and poor immunity.

Cushing’s Syndrome
Equine metabolic syndrome is sometimes referred to as Cushing’s Syndrome, because it is a factor in the development of Cushing’s Syndrome. Previously thought to be caused by a tumour in the pituitary gland (a small endocrine gland at the base of the brain), Cushing’s is a result of advanced equine metabolic syndrome as caused by high-sugar diets and erratic hormones levels in the blood.

The chronically elevated levels of insulin cause the adrenal glands to increase the production of cortisol and corticosterone – steroid-like hormones that normally combat stress, decrease inflammation and regulate carbohydrates. Elevated cortisol levels, however, also increase blood sugar, depress the immune system, increase weight, dissolve bone density, weaken the muscles and catabolize connective tissue – including the lamina. This causes the pituitary gland to increase its levels of ACTH (adenocorticotropic hormone) in an effort to regulate the cortisol levels.

If the underlying cause – high starches and a lack of exercise – isn’t resolved the excess production of ACTH leads to fatigue, sweating, curly hair, and slow shedding of the hair coat. It is not unusual for the thyroid to become less active too – thyroid hormones are suppressed in the presence of high insulin and high cortisol levels. These collective hormone imbalances exacerbate and perpetuate weight gain, stress, digestive problems, poor immunity, fatigue and laminitis.

Because of the highly vascular nature of the horse’s hoof it is extremely susceptible to inflammation and damage especially from digestive toxicity. Once the laminar tissue becomes weakened the connection between the hoof wall and coffin bone begins to separate causing pain and inflammation. While not all metabolic horses are laminitic, the three main causes of laminitis are insulin resistance, leaky gut and Cushing’s Syndrome.


Equine Metabolic Syndrome (EMS) is the result of modern horsekeeping, mostly caused by the lifestyle that humans have created for the domesticated horse. And so it is that the responsibility lies on us as the horses’ care-givers to eradicate this unnecessary disease. With proper management of diet, exercise and horse-keeping, the symptoms of metabolic syndrome and laminitis can not only be reversed, but most horses can be rehabilitated to the point of being completely well again.

Ask Bernice, the owner of Kazak. ‘Zak’ is a 22-year-old Arab gelding living in Calgary, Alberta. His story came to me in October 2005, when he was 16 years old and already showing the visible signs of EMS and Cushing’s. Zak was at least 100 pounds overweight, with fat pads around his tail head and his shoulders, a pot belly, a long coat that got curly when he was wet (he looked like a buffalo), easy sweating, runny and dull-looking eyes, depression and a low energy level. Needless to say, Zak loved food. His diet consisted of grass pasture, crushed oats, four to five carrots per day and a molasses based vitamin and mineral mix.

The first thing we addressed was Zak’s diet. We switched him from grass pasture to grass hay and eliminated his oats, carrots and vitamin mix. Zak’s first supplement program consisted of Vitamin B6, Vitamin B12 and folic acid to support blood sugar levels, liver function and digestion, as well as herbal colon cleansers and probiotics to detoxify the colon, slow down sugar absorption and encourage better digestion of fibre and nutrients.

Zak’s initial response to his new lifestyle was weight loss, an increase in energy and improved shedding. A few weeks later, we focused his program on pituitary and thyroid function, as he continued to sweat, and his energy levels and depression were somewhat erratic (the long years of excess weight and high dietary sugars had taken its toll on his hormones). Zak started Siberian ginseng to improve the overall endocrine hormone function.

Throughout Zak’s recovery, Bernice always continued to ride him regularly – at least four to five times per week, even if his exercise was kept to a walk. She often stated that she would feel terribly guilty doing it, especially on days when he was so tired and depressed, but she knew that his exercise program was a significant part of his healing journey. Zak made a gradual recovery and continued to improve every step of the way. Today, Zak is completely recovered – healthy, happy, ridden regularly and looking like a horse, rather than a buffalo.