On big roundups that often last many weeks or months on the large ranches of the west, each cowboy must have a number of horses to ride. The horses that are assigned to the cowboy are called his string. There may be ten or more horses assigned to each man. He is responsible to take care of them and no one else can ride them without his permission. All the strings combined form a herd called the remuda (a Spanish word for a herd of horses). About the break of day the remuda is rounded up and run into a rope corral formed by the men and their lariats. Each man selects his mount for the morning ride. They are roped and brought out to the men. In this particular scene, the cowboy has tied up the horses hind leg with a soft cotton rope to insure that the horses pastern will not be burned or cut. Tying the horse in this manner insures that the cowboy will be able to saddle him and get on board before he bucks, if he's inclined to.