Simplify the following text for a Grade 4 native English-speaking person.
Original: Historically , `` ox '' was a non-gender-specific term for adult cattle , but generally this is now used only for draft cattle , especially adult castrated males . The term is also incorporated into the names of other species such as the musk ox and `` grunting ox '' ( yak ) , and is used in some areas to describe certain cattle products such as ox-hide and ox-tail .
Simplified: Ox is the usual word for working cattle .