Equine Metabolic Syndrome in Horses: Cause, Symptoms and Treatment

Puggy horses have become a typical sight in our stables and pastures. It is not uncommon to see robust breeds, ponies, small horses and cold-blooded horses affected by overweight. Excess weight on the ribs of our domestic horses is a serious matter, as the fat deposits put a massive strain on the body. The result can be ametabolic disease. We are talking about Equine Metabolic Syndrome, or EMS for short. EMS is a clinical syndrome that is accompanied by a complex of symptoms and, in the worst cases, results in laminitis.

Equine Metabolic Syndrome (EMS) - What is EMS?

The metabolic disorder EMS is not known from wild horses. Equine metabolic syndrome is a disease of affluence that deliberately affects our domestic horses. Unlike their wild relatives, they do not have to roam through barren areas to find enough grass. Our horses usually go to pastures and paddocks where the food supply exceeds their needs. They then return to their stables and are often given a scoop of muesli or oats. Every now and then they are allowed to "work" a little, although the word "work" is an exaggerated term for many leisure horses.

The overabundance of feed in combination with too little exercise leads over time to overweight and prominent fat pads on the mane ridge, above the eye and along the back. Apart from the fact that the high weight has a negative effect on joints and bones, the fat pads can throw the organism as a whole out of balance. Gradually, a symptom complex develops that, in the worst case, results in type II diabetes and laminitis.

The tricky thing about EMS is that it is a vicious circle that forces the horse further and further into its health problems. The only way to break this cycle is to restore a balance between posture, feeding and exercise. More on this later. Let's first clarify how exactly EMS develops in horses.

➡️ Video tipEMS - The disease with the fat pads! Learn about the risks of obesity for horses, how to keep your horse's weight healthy and what Equine Metabolic Syndrome (EMS) is all about - including tips on weight control!

Equine Metabolic Syndrome (EMS) in Horses: Causes

In healthy horses, the glucose level in the blood rises after feeding, but is quickly lowered back to a healthy level by the pancreatic hormone insulin. If the blood glucose level falls below a certain level, insulin's antagonist glucagon comes into play and raises it again.

In EMS horses , however, this sugar metabolism is disturbed. The horses consume large amounts of feed, which means that the glucose level rises, whereupon insulin is released. Insulin is responsible for transporting the glucose molecules from the blood into the body cells, where they are made available to the body as energy. However, if the horse is not sufficiently exercised and worked, this energy is not needed and is therefore stored as a fat reserve. 

By nature, horses are designed to absorb carbohydrates slowly, which is why there are normally no noticeable peaks in blood sugar levels. Although horses can cope well with one of these peaks from time to time, an oversupply of palatable feed leads to a permanently high blood sugar level. Insulin production is constantly boosted until the hormone becomes ineffective - insulin resistance develops and the metabolism goes haywire.

At the same time, the fat pads are not just fat: the fat pads along the topline that are typical of EMS horses also release hormones that are involved in inflammation, including stimulating the release of cortisol in the adrenal cortex. Cortisol in turn inhibits insulin, the blood sugar level rises even further and even more ineffective insulin is released - creating a vicious circle.

The inflammatory substances in the body increase with the increase in fat cells and the toxic messenger substances in the circulation kill off the healthy body cells, which lowers the immune defense. The flood of toxins also damages the liver, which can no longer adequately perform its task as a detoxification organ, so that the culmination of the creeping process is laminitis caused by feeding or hormones.

Because EMS is a gradual disease, it is often only recognized late. The symptoms can also be very similar to those of Cushing's symptoms. The risk of making an incomplete or incorrect diagnosis in EMS horses is very real. Due to the already high inflammation levels and the stimulation of cortisol, treatment with cortisone, for example, would be fatal as it further promotes insulin resistance. The vet must therefore investigate the cause of a fat horse to make sure that it is actually equine metabolic syndrome.

‍EMShorse symptoms

The wobbling fat neck and other fat pads along the back up to the base of the tail are not only a typical symptom of EMS in horses, the fat and excess weight are also the cause of the metabolic disease. A horse with EMS has a body condition score of 7 on a scale of 1 to 9. The horse then carries around a clear groove over the spinous processes, the ribs can no longer be felt under the layer of fat, a second udder of fat forms in mares and the tube is also enlarged in geldings and stallions. In addition to fat pads, there are other external and behavioral changes and

If the horse's overweight is not tackled, EMS results in laminitis. So if the signs of EMS are not recognized in time to counteract them, the scenario can end in a super-GAU.

The vicious circle of the disease can be further promoted by leptin resistance. Leptin is considered a natural appetite suppressant and is one of the most important fatty acids in the horse, which is released by the fat pads. We all know it, the horse looks so sweet, then there's an apple here, a banana there, a treat there and so on. But beware! However, if the horse is given an oversupply of appetizing things, it will eventually become resistant to leptin and develop a gluttonous appetite. Hunger attacks then characterize the horse's behaviour.

➡️ Video tip: The spectre of laminitis - when every step hurts! Learn all about the causes, symptoms and dangers of this serious inflammation, including the risks of coffin bone drop and coffin bone rotation, from experts at the Karthaus Veterinary Clinic!

‍EMS and Cushing's - What are the Differences?

A correct diagnosis of EMS is therefore of the utmost importance for the long-term health of the horse. However, EMS is sometimes difficult to distinguish from the hormonal disorder Cushing's syndrome (PPID), especially in the early stages. Many of the symptoms overlap, making diagnosis difficult. Nevertheless, EMS and Cushing's are clearly distinguished from each other by a few points:

➡️ Reading tip: You can find out all about the common metabolic disease, its effects on horses and how it can be diagnosed and treated here.

How is EMS Diagnosed in Horses?

Especially in its early stages, EMS can easily be associated with Cushing's syndrome (PPID) can easily be confused with Cushing's syndrome (PPID). Symptoms such as loss of performance, muscle loss or a weakened immune system also indicate an infectious disease, viral or other metabolic disease. Therefore, in addition to the clinical examination of the symptoms, the diagnosis must be based on the blood count. To find out whether the horse is suffering from EMS, the insulin levels in the blood and blood lipid levels are examined closely. One way of doing this is to determine fasting insulin and fasting glucose levels: the test is carried out on an empty stomach for at least six hours. This is because the values are most meaningful then and are not influenced by the nutrient content of the food.

In order to make a truly reliable diagnosis of EMS and not Cushing's the test is repeated within three weeks, as a single test could be falsified by performance, stress, season or other illnesses.

On the other hand, there is the somewhat complex combined glucose-insulin test (cGIT) and the oral glucose tolerance test (OGT). In the latter, the horse is sobered up overnight and given sugar water via a nasal tube the next morning. After just two hours, the insulin levels are measured. In a healthy horse, the insulin value is below 68 mU/I insulin. In order to avoid a misdiagnosis and therefore incorrect therapy, the ACTH value is also measured in older horses to rule out Cushing's disease.

‍The Treatment of EMS in Horses

If equine metabolic syndrome (EMS) has been diagnosed, there is still something that can be done about it. Because EMS is treatable. However, anyone hoping for a miracle cure is wrong. EMS horses cannot be treated with medication for their pathogenic obesity. The only way out of the EMS vicious circle is to lose weight early on: With an adapted feed and exercise, exercise, exercise. A well-thought-out EMS horse training plan or weight loss plan can also help with EMS to keep track of progress. Even though exercise is a super important factor in the weight loss process, the regeneration process of the horse with EMS must be taken into account. Because if you want to lose a few pounds yourself and go from 0 to 100 overnight, you can expect pain, if not injury, in at least a week.

Why exercise is so important for EMS horses

Exercise is a central component of the treatment of EMS horses, as it improves insulin sensitivity, stimulates the metabolism and at the same time reduces fat reserves. Just 20 minutes of walking can significantly improve insulin sensitivity. The sugar in the blood is used immediately through exercise and is not stored as fat in the first place. It also increases fat burning, builds muscle mass and strengthens the cardiovascular system.

Lose weight properly: EMS horse training plan

If a horse already has EMS, it is important to clarify whether laminitis or other illnesses that negatively affect the horse's musculoskeletal system have also occurred. Then the training goalshould be discussed with the vet, is it realistic to pursue the goal or does the vet advise you to start with small steps first?
Basically, it can be said that a good EMS training plan for losing weight with EMS must be individually adapted to the needs and attitude of the horse.

Customize a training plan

An individually tailored EMS training plan is essential in order not to overtax the EMS horse, but still to challenge it effectively. How intensively a horse needs to be moved and trained with EMS depends, among other things, on any hoof rehabilitation strain.

• Laminitis is a burden: Once the flare-up has subsided and the horse has a stable hoof situation, it can be worked at least four days a week with no or light rider weight. 30 minutes of brisk trotting and calm cantering are appropriate.
• Without laminitis: If the EMS horse does not have laminitis, it can also be worked up to six days a week with and without a rider. This involves at least 30 minutes of work with lots of concentration, activation of the forehand and hindquarters and canter units.

A good EMS training plan for weight loss should also be adapted to the horse's posture.

• Open stable: If the horse is in an open stable where there are enough incentives to move around independently, the training sessions will vary in comparison to a horse that is only stabled and comes out to the paddock or in the horse walker for a few hours a day.
• All types of stabling: In general, however, horses in open stables can also get EMS and, just like horses from other types of housing, must have a good training plan to get EMS under control.

Endurance and fitness training

In addition, endurance and fitness training proves to be an important key to weight loss. Walks, rides through hilly or uneven terrain and calm trotting and cantering sessions not only improve the EMS horse's stamina and endurance, but also its coordination.

Gradual increase

Start taking your horse for a walk or doing small laps around the yard. These can then be extended on a weekly basis. But be careful! Don't plan a trail ride lasting several hours overnight, but increase your training slowly. Intensive training in the anaerobic range can lead to muscle acidification and additional strain on the detoxification organs.

Consultation with the vet

As a general rule, both the diet plan and the training plan should always be drawn up in close consultation with the attending veterinarian in order to take the needs of the individual horse into account. With a targeted training plan and a gradual increase in exercise, the symptoms of EMS can be effectively combated and the horse's well-being can be sustainably improved.

➡️ Reading tip: You can find out how to create a good training plan here.

Feeding an EMS horse: What you should bear in mind

➡️ Video tipFeed EMS horses correctly! Find out why low-energy roughage, the right hay/straw mix and hay soaking are essential for your horse's health - for optimum support with EMS!

Even the best training plan for horses with EMS cannot do without an adapted diet. An absolute zero diet must be avoided at all costs! Instead, the horse should be given low-energy roughage, preferably cut late and consisting of 2/3 hay and 1/3 straw. More straw should be avoided due to the risk of constipation colic. For EMS horses, 1% hay per body weight is completely sufficient for basic maintenance. A small horse with a body weight of 480 kg should therefore receive around 4.8 kg of hay - no less! not less! The hay can also be soaked for at least 30 minutes. As a rule, horses with EMS and overweight do not need concentrated feed.

➡️ Video tipHow much energy does a horse need? Dr. Patricia Sitzenstock explains how to determine your horse's energy requirements, what energy is needed for and how to optimally adjust the feed accordingly - for healthy and balanced horses!

Which Mineral Feed Do You Feed an EMS Horse?

A complete mineral feed with a low sugar and starch content is important when slimming down in order to compensate for the missing nutrients from any roughage that may have been washed out. The manganese value in particular should be examined here. It is not uncommon for EMS horses to have a manganese deficiency. Manganese is an important player in sugar metabolism and is closely linked to the hormone glucagon. If there is a manganese deficiency, this can lead to undesirable food cravings because the blood sugar level is no longer raised after it has been lowered by insulin.

You Should Avoid These Foods if Your Horse Has EMS

The following feedstuffs are taboo for EMS horses: sweets such as apples, bananas and bread, which only unnecessarily raise blood sugar levels. Haylage, grass silage, flavorings, preservatives and sweeteners are also a no-go for EMS horses. These affect the liver and put a strain on it so that the toxins released during the weight loss process cannot be filtered out. A damaged liver also means laminitis again.

Horses with EMS should be supported in their diet for the sake of their liver by herbs such as milk thistle, birch leaves, nettle and dandelion.

And as sorry as it is, the lush, green pasture is also canceled for EMS horses. As an emergency solution, it may be possible to resort to a muzzle, with which the horse can still experience the time in the pasture with his pals.

EMS horse: Summarized:

Equine metabolic syndrome (EMS) is a serious disease in horses, which is mainly characterized by obesity and metabolic disorders. This metabolic syndrome in horses occurs particularly in robust breeds, ponies, small horses and cold-blooded horses. EMS in horses is caused by a combination of excessive feeding, lack of exercise and genetic predisposition. This disease of affluence leads to fat deposits, insulin resistance and inflammatory processes in the body. EMS horses can suffer from a variety of symptoms that need to be recognized in time to avoid more serious consequences such as laminitis.

Typical EMS horse symptoms include fat pads on the eyes, mane ridge, back and tail base, ravenous appetite, loss of performance, dull coat and stiffness of movement. Particularly noticeable is the so-called "fat neck", which often serves as an indicator of EMS disease. EMS in horses develops gradually, which is why symptoms such as a high body condition score or watery stools are often only noticed at a late stage.

The diagnosis of equine metabolic syndrome requires specific tests, including the determination of insulin levels in the blood. It is important to differentiate EMS symptoms in horses from other diseases such as Cushing's syndrome.

The EMS horse treatment focuses on adapted feeding and targeted exercise training. An individually tailored training plan that promotes stamina and condition is essential. In addition, low-energy roughage should be fed, supplemented with a high-quality mineral feed. Sweets and concentrated feed must be avoided in order to relieve the metabolism. Metabolic syndrome in horses can be successfully treated in this way, even if it requires a long-term change in husbandry and feeding.

Prevention remains the best way to avoid EMS in horses. Balanced husbandry, controlled feeding and regular exercise are crucial. Horse owners should pay particular attention to EMS horse symptoms on the eyes, mane ridge and tail base. Pictures and further information on EMS horses can help to recognize the disease at an early stage and take action.

With the right combination of feeding, exercise and veterinary support, the consequences of metabolic syndrome in horses can be contained and the quality of life of the animals improved in the long term.

FAQS: Frequently asked questions about EMS in horses

How do you recognize EMS in horses?

EMS can be recognized by fat pads on the mane crest, base of the tail and above the eyes, combined with overweight and a tendency to laminitis.

Which treats are suitable for EMS horses?

EMS horses can be given low-sugar treats such as carrots in moderation, special EMS horse treats or unsweetened vegetables.

What should an EMS horse not eat?

EMS horses should not be given sweet snacks such as apples, bananas, bread or grass silage. These contain too much sugar and put a strain on the metabolism.

How do you feed an EMS horse?

An EMS horse is best fed with soaked hay, lean roughage and low-sugar mineral feed. Concentrated feed is usually not necessary.

How is EMS treated in horses?

The treatment of EMS includes an adapted diet, plenty of exercise and, if necessary, the use of medication to improve insulin sensitivity.

How long can an EMS horse eat grass?

EMS horses are only allowed to eat grass to a very limited extent, ideally in a pasture low in fructan and with a muzzle to control feed intake.

Which nutritional supplements are useful for EMS horses?

Supplements such as low-sugar mineral feed, milk thistle, nettle and dandelion can support the metabolism and liver function.

Is EMS hereditary in horses?

Yes, EMS has a genetic component and is particularly common in robust breeds, ponies and cold-blooded horses. The probability is partly hereditary.

Can EMS in horses be improved with exercise?

Yes, regular exercise improves insulin sensitivity, helps with weight loss and supports metabolic function.

How does EMS develop in horses?

EMS is caused by a combination of genetic predisposition, overfeeding and lack of exercise, which leads to obesity and insulin resistance.