Cows are livestock members of the Bovidae tribe and children of the Bovinae tribe. Cows that have been castrated and are usually used to plow fields are called oxen. Cows are raised mainly for the use of milk and meat as human food. By-products such as skin, offal, horns, and feces are also used for various human purposes. In a number of places, cows are also used as a means of transport, processing planting land (plow), and other industrial tools (such as sugar cane squeezers). Because of these many uses, cows have been a part of various human cultures for a long time.