What are mature male cattle called?

A bull, also known as a sire, is a mature male bovine that is at least 2 years old and used for breeding purposes. Bulls are usually not used for meat. Bulls are usually larger than other cattle. They have large, muscular shoulders, necks, and hindquarters. A hump is usually noticeable on its shoulders. When bulls are full-grown, they can weigh as much as 2,000 pounds.

Source: Farm and Dairy