Weight loss and fat cell reduction through diet and exercise is the mainstay for treatment of this condition, as well as tests to check for the presence of the disease “Cushings”.
A reduction of total calorie intake as well as basic carbohydrate intake is crucial.
Soaking hay for at least one hour is also essential. Soaking hay acts to dilute out the starch and sugar content. Every case is different and we will tailor the diet specifically to your horse. However, as a rough guideline, to achieve weight loss in an obese horse the initial aim should be to feed 1-1.5% of the horse’s body weight as dry forage daily. The total quantity of hay is measured out as dry matter before it is soaked. For example, a 400kg pony should be fed 4-6 kg of hay (which should then be soaked for a minimum of 1 hour) per 24 hours as a maximum. Any additional feed such as low calorie chaff containing vitamins and minerals, is weighed out and subtracted from the total daily allowance, e.g. 1kg of chaff fed split between 2 feeds, should leave a 400kg pony having 3-5kg of hay in 24 hours.
After an acceptable body weight has been reached, depending on your vet’s advice, the quantity of feed may increase but it never should go above 2-2.5% of the horse’s body weight as a daily ration.
Metformin is a medication which has variable results in treatment of insulin resistance. Its effects are thought to include creating increased insulin sensitivity in tissues and decreased production of glucose by the liver. It also is thought to block glucose absorption by the gut. Whilst its effects are still debated, it remains one of the only medicines we can use to treat this condition.
A very recent study has found metformin to be most useful in the later stages of treatment of insulin resistance. The use targeted in the study was for the period of time after the horses have been dieted and reached a goal weight. It was found to be beneficial as a treatment for horses that are starting to return to a more normal life and beginning to be reintroduced to small amounts of grazing again.
Much more research is still needed. Metformin has been thought to be successful in some horses, but not in others such as obese mares which are reported to be least responsive. There are a variety of low calorie enrichment ideas suitable for the EMS-risk pony.