Swellings in horse's legs are a very common event. As such many of the most common ones have developed a specific term used by horsemen. Stocking up is one of those terms defined as a normal temperature, non-painful, usually bilateral, swelling of the lower legs. This swelling will pit on firm finger pressure and when released will slowly refill in 5 to 30 seconds. Most often in the hind legs, occasionally the fronts or even a single leg is effected. The definition differentiates it from other cool swellings like windpuffs, firm swellings like splints or ring bone, or any swelling associated with hot painful legs. This article will describe the causes, treatment and prognosis of stocking up.

Stocking up is the accumulation of excess fluid in the subcutaneous tissues of the leg and in medical parlance is called non-inflammatory edema. Healthy blood vessels are really quite “leaky”. The fluid that leaks out is picked up by the lymphatic system and returned to the blood. Any process that either speeds up the leak or decreases the return can cause a horse to stock up. One of the processes that both slows the leaking and increases the return is the tissues natural elasticity. The skin, subcutaneous tissues, connective tissues etc all have a certain amount of elasticity that exerts pressure helping to keep the sub-q fluid to a minimum. Exercise also helps to push this interstitial fluid along the lymphatics. Other causes of edema are:

• Increase blood pressure particularly venous pressure
• Decrease in lymphatic flow
• Decrease in the amount of protein in the blood