Oxen (singular ox) are bovines trained as draught animals. Often they are adult, castrated males. In New England and Maritime Canada, the term oxen refers to trained steers at least four years of age. Prior to age four they are referred to as handy steers. Oxen are used for ploughing, transport, hauling cargo, threshing grain by trampling, powering machines for grinding grain, irrigation or other purposes, and drawing carts and wagons. Oxen were commonly used to skid logs in forests, and sometimes still are, in low-impact select-cut logging. Oxen are most often used in teams of two, paired, for light work such as carting. In the past, teams might have been larger, with some teams exceeding twenty animals when used for logging.