What happens if I leave my horse with a full winter coat and continue working him?
A horse with a full winter coat will sweat if worked. This mechanism cools the horse, but if it doesn’t do so sufficiently, the body temperature will rise and the horse may even collapse. When the horse stops work, it will cease sweating, but will be wet. This moisture will gradually evaporate and the horse dries off. In order for water to evaporate, it needs energy in the form of warmth, which it takes from the horse. This robs the horse of condition, and can cause chilling, even to the point of hypothermia.
The chilled horse will shiver in an effort to maintain its body temperature, which in itself further depletes energy and body condition. So if the horse is need to work on a regular basis during the winter months, it is in the horse’s best interest to keep him clipped to some degree depending on the amount of work that is required from him.