A horse harness is a type of horse tack that allows a horse or other equine to be driven and to pull various horse-drawn vehicles such as a carriage, wagon or sleigh. Harnesses may also be used to hitch animals to other loads such as a plow or canal boat.
There are two main categories of horse harness: the "breaststrap" or "breastcollar" design, and the collar and hames design. For light work, such as horse show competition where light carts are used, a harness needs only a breastcollar. It can only be used for lighter hauling, since it places the weight of the load on the sternum of the horse and the nearby windpipe. This is not the heaviest skeletal area ; also heavy loads can constrict the windpipe and reduce a horse's air supply.
By contrast, the collar and hames harness places the weight of the load onto the horse's shoulders, and without any restriction on the air supply. For heavy hauling, the harness must include a horse collar to allow the animal to use its full weight and strength.
Harness components designed for other animals (such as the yoke used with oxen) are not suitable for horses and will not allow the horse to work efficiently.
Putting harness on a horse is called harnessing or harnessing up.
