By Dr Thomas Burke BSc. DVM
Equine metabolic syndrome (EMS) is a complex metabolic disease that has only recently started to be well understood within the Veterinary profession. Generally, Veterinarians are most concerned with EMS in relationship to predisposing horses/ponies with developing Laminitis.
The cause of EMS is multifactorial; current research suggests it is a combination of genetic factors with excess calorie intake and sedentary lifestyle which leads to obesity/insulin dysregulation. Ponies in general appear to be more at risk of developing EMS, with some breeds that appear to be over represented including Welsh, Dartmoor and Morgan. EMS susceptible ponies/horses are thought to have “thrifty genes” which in the past have served them well to maintain condition in harsh environments. However due to the nature of domestication and improvement of pastures these genes are now doing them more harm than good.
Some of the known causes linked to EMS developing include genetic predisposition, excess calorie intake and sedentary lifestyle as risk factors. These characteristics leads to obesity or regional adipose tissue deposits (e.g. cresty necks). In horses or ponies that are susceptible to EMS the increase in adipose tissue, in combination with dietary sugars and starches can lead to insulin dysregulation. Insulin dysregulation occurs when either the body’s cells don’t respond to insulin, leading to increased insulin being secreted to control blood sugar, or an excessive insulin response to sugars and starches in the diet. When a combination of insulin dysregulation and obesity are placed together the horses/ponies go through a series of blood changes that can cause disruption to the laminar vessels and overall cause serious inflammation of the hoof lamellae (Laminitis).
Veterinarians usually have a suspicion that EMS is playing a role in your horse/pony developing laminitis by the patient’s age, body condition score and the time of year. However, there are a variety of syndromes that can lead to laminitis, including PPID (Cushing’s disease), grain overload or endotoxemia that should also be evaluated. The preferred method of testing if your horse/pony has susceptibility to EMS and therefore laminitis, is the In-feed glucose test. This test involves fasting the horse overnight and then taking a blood sample to test for serum insulin and plasma glucose. The horse is given a small feed with a known quantity of sugar, and a second sample is taken two hours after the feed is eaten. This test provides excellent information not only to help diagnose EMS, but also to determine the actual risk of your horse developing laminitis, unless management changes are made.
Changing a range of lifestyle factors can help reduce insulin resistance in horses and ponies by reducing the amount of dietary sugar, adipose tissue and insulin responses. These include introduction of exercise programme and reduction of non-structural carbohydrates (sugars and starches) in the diet. While diet and exercise are the mainstay of control (assuming your horse does not have laminitis), we sometimes use medication to aid weight loss and help reduce the risk of laminitis further.
If you would like to know more about EMS, or EMS testing for your pony, please feel free contact us on 0895303751 to talk to one of our friendly team members. Remember, spring will be on us before you know it, so now is the time to act!
