Swollen joints are always cause for concern, but if both of your horse’s hind fetlocks become puffy in the dead of winter, chances are the cause is a relatively harmless condition known as “stocking up.”
Rather than injury or infection, stocking up is a function of inactivity. The equine lymphatic system, which is responsible for “pumping” excess fluids from between cells back into the circulatory system, works best when aided by movement of surrounding tendons, muscles and ligaments. So when a horse stands still for long periods of time---as he may when confined to a stall during winter months---these fluids can accumulate, particularly in areas farthest from the heart. Most commonly, stocking up is seen in the hind fetlocks, with severity ranging from mild puffiness to an extreme swelling, giving the leg a “stovepipe” appearance. Stocking up doesn’t cause lameness or affect the gait, and each leg will be equally puffy.
Treating stocking up is easy. Simply ride your horse, walk him by hand or turn him out with a companion. With activity, swelling will usually diminish within the hour. But be prepared for the puffiness to return: Many horses stock up repeatedly. Part of the reason is that once the tissues between cells are stretched by accumulating fluid, they are more susceptible to filling again. You can try to prevent the swelling with standing bandages, but there’s no physiological reason to do so, and putting bandages on too tightly can create more serious problems than stocking up.
AT A STANDSTILL: Stocking up, a harmless accumulation of fluid in the lower legs, is associated with inactivity. It usually occurs in the hind fetlocks.