Laminitis and subsequent founder are devastating conditions that can develop in horses, and the most common causes are related to the amount of insulin in the blood. Laminitis and founder most commonly develop in horses that have Cushing’s disease or equine metabolic syndrome. In both of these conditions, the underlying cause of the condition is increased insulin in the blood. In Cushing’s disease, horses get a growth on the pituitary gland located at the base of the brain, which produces hormones; the hormones decrease insulin sensitivity, which makes the horse insulin resistant, thus increasing levels of insulin in the blood. In equine metabolic syndrome, horses are resistant to the effects of insulin and gain weight very easily, thus earning the title easy keepers. Some horses can also founder from simply eating too much pasture grass, and these horses are fat. Horses with equine metabolic syndrome do not necessarily eat too much but they eat too many carbohydrates and this increases insulin in the blood.
So certainly if your horse has ever foundered, the insulin levels should be checked as the cause may be one of these underlying diseases. However, Dr. Steve Grubbs indicated recently at a meeting in Denver that there are characteristics you should look for to get an idea if your horse may have high insulin levels. In Cushing’s disease, horses get a growth on the pituitary gland located at the base of the brain, which produces hormones; the hormones decrease insulin sensitivity, which makes the horse insulin resistant, thus increasing levels of insulin in the blood\ fat pads and those that have foundered were overtwo times more likely to have high insulin levels in the blood than those without these symptoms. Horses with high sugar levels in the blood were almost five times more likely to have high insulin levels. So if you have a horse that has abnormal sweating, laminitis, a cresty neck (looks similar to the crest of a mountain range) and a pot belly, it is likely the horse has high insulin levels and should be tested.