From the time of the invention of the horse collar, horses became more valuable for plowing and pulling. When the horse was harnessed in the collar, the horse could apply 50% more power to a task in a given time period than could an ox, due to the horse's greater speed. Additionally, horses generally have greater endurance than oxen, and thus can work more hours each day. The importance and value of horses as a resource for improving agricultural production increased accordingly.