Equine Metabolic Syndrome
Equine Metabolic Syndrome is a rather new term used to describe horses with what is thought to be a genetic predisposition that leads to obesity, insulin resistance and laminitis.
Other Names for Equine Metabolic Syndrome
Equine Metabolic Syndrome, EMS, Prelamintic Metabolic Syndrome, Peripheral Cushing’s Syndrome.
Causes of Equine Metabolic Syndrome
It is thought that horses have a genetic predisposition for EMS.
Some breeds, ponies in particular, seem to more likely to get EMS than others. Paso Finos, Arabians, Spanish Mustangs, Quarter Horses and other breedsthat come from an ancestry of horses that lived in harsh conditions appear to develop EMS more easily than horses like Thoroughbreds and Standardbreds. My mare is a Paint and Thoroughbred cross and undoubtedly has some Quarter Horse in her background.
Equine Metabolic Syndrome has three characteristics. Horses with EMS tend to carry fat along the tops of their necks, over the top of tail, behind the shoulders or in the udder/sheath area. Even when my mare becomes leaner through dieting and exercise, she still has a pad of very hard fat along the top of her neck. Horses with EMS become insulin resistant. Insulin resistance is determined by a veterinarian who measures the insulin and sugar levels in the blood.
The third characteristic of EMS, and most devastating, is laminitis. While my own horse does not have laminitis, I do worry that her apparently tender soles are an indication that without proper management, full blown laminitis could easily develop. (As it it, the only way I have been able to keep her feet comfortable is with shoes, as much as I would prefer to keep her unshod.)
EMS tends to affect horses in the prime of their lives, unlike Cushing’s Disease which affects horses in their senior years. EMS in horses is similar to Metabolic Syndrome in humans.
EMS is controlled by managing a horses diet and exercise regime. Pasture grass should be limited, especially in spring or when pasture is rebounding after a drought as quickly growing grass is high in carbohydrates that need to be limited. All feeds need to be low energy foods and concentrates; especially those made with high energy ingredients like sweet feed with molasses orcorn should be eliminated. When a hay only diet doesn’t provide enough nutrients low calorie commercial feed can be fed, along with beet pulp without molasses, and vegetable oils to replace the carbohydrates without affecting the horse’s insulin levels. This is similar to a low glycemic dietfor humans. Horses with severe EMS may never be able to graze at pasture, while some may be able to tolerate a brief grazing time—say an hour or so a day.
Exercise is also essential and being a pasture potato is not good for any horse. Regular exercise is good for a horse (and human). Despite my mare’s assertions that her role is to eat and look pretty, having a steady job is good for her. Of course, if a horse with EMS has developed laminitis, theveterinarian will be able to advise on how to exercise it without causing pain.
So far, there are no drugs that have satisfactorily prevented or treated EMS. If the EMS horses develops laminitis, drugs may used to treat the inflammation and pain.
Pity poor Trillium in her diet pasture as she gazes longingly over the fence watching her buddies dine on green grass or rich second cut hay. But, the only way to prevent the onset of EMS may be to prevent a horse becoming obese in the first place.