Spring is here and with it comes that fresh growth of grass.
Suppose you had two horses –
One a fit young thoroughbred
One middle aged, live-off-the-smell-of-an-oily-rag pony
Why is the pony more likely to develop laminitis during this spring flush?
The reason is that some horses, typically easy-keepers, are genetically predisposed to respond to dietary non-structural carbohydrate (sugars and starch) differently – their cells are less responsive to insulin, i.e., they have “insulin resistance”.
Insulin is a hormone normally released after a meal that signals the body tissues to take up and store glucose. With insulin resistance, typically even more insulin is released to overcome a lack of sensitivity to this hormone.
This results in high circulating insulin levels: Either just after a meal or all day.
This is similar to the metabolic abnormalities that accompany type 2 diabetes in humans.
In horses, the insulin resistance is associated with two endocrine conditions –
Equine Metabolic Syndrome (EMS)
And Cushings Disease (PPID)
So, what has this got to do with laminitis? High levels of insulin over a sustained time period has been shown to cause the painful condition, laminitis – weakening of the tissues (laminae) that anchor the hoof wall to the bone.
Can we test for insulin resistance? Yes, the most sensitive test involves feeding your horse a meal containing glucose powder and then checking blood insulin levels 2 hours later. We can also test for PPID by checking blood ACTH levels.
Can we treat it? Although we cannot change the genetic predisposition, we can enhance the insulin sensitivity of the tissues through dietary management and exercise. We can also use medications to help control PPID and EMS.
Be on the lookout for any signs of foot pain – mild laminitis can be hard to detect because it affects both feet so the only sign your horse might show is moving around less or being reluctant when ridden. Prevention is always better than the cure, so if you are concerned about your easy-keeper call us for a health and nutritional assessment.