Q: What is stocking up?

A: Stocking up is a phrase used to describe what happens to a horse’s legs when they swell up below the knees. Commonly owners report that a horse swells up below the knees after a night spent in the stable, but then after turn-out in the paddock, the swelling goes back down. Usually, both fronts or backs, or all four legs, will be swollen in stocking up. Stocking up differs from swelling due to injury in that the horse is usually not lame, and the swelling is generalised, not specific to one location or leg.

The most common reason for stocking up is a lack of movement. Horses are designed to be on the move most of the time. Through contraction and expansion of the digital cushion in the hoof (among other things), this movement helps to move blood in the circulatory system back to the heart. If a horse is left in a stable for a while, the circulatory system cannot work as effectively due to the lack of movement, and fluid will pool in the tissues, causing oedema. This fluid pools in the lowest point of the horse due to gravity, leading the legs to appear puffy and swollen. Some horses may also stock up due to heart issues or problems with the lymphatic system. Therefore, it is worth confirming with your vet that the stocking up is simply caused by a lack of movement and then trying to find ways to maximise your horse’s ability to move during the day.