A horse collar is a part of a horse harness device used to distribute load around a horse's neck and shoulders when pulling a wagon or plow. The collar often supports and pads a pair of curved metal or wood pieces, called hames, to which the traces of the harness are attached. The collar allows a horse to use its full strength when pulling, essentially allowing the horse to push forward with its hindquarters into the collar rather than to pull with its shoulders as it would be required to do if wearing a yoke or a breastcollar. The collar is also an improvement on the yoke as it reduces pressure on the windpipe. From the time of invention of the horse collar, horses became extremely valuable for agricultural success and for pulling heavy vehicles. When the horse was harnessed with the horse collar, the horse could provide a work effort of 50% more foot-pounds per second because of greater speed than the ox, as well as having generally greater endurance and ability to work more hours in a day. The horse collar was important in the development of Europe, as the replacement of oxen with horses for ploughing boosted the economy, reduced reliance on subsistence farming, and allowed the development of early industry, education, and the arts in the rise of market-based towns.