A Hereford bull In general, the same words are used in different parts of the world, but with minor differences in the definitions. The terminology described here contrasts the differences in definition between the United Kingdom and other British-influenced parts of the world such as Canada, Australia, New Zealand, Ireland and the United States. A wild, young, unmarked bull is known as a micky in Australia. An adult female that has had a calf or two, depending on regional usage is a cow. Young cattle of both sexes are called calves until they are weaned , then weaners until they are a year old in some areas; in other areas, particularly with male beef cattle, they may be known as feeder calves or simply feeders. After that, they are referred to as yearlings or stirks  if between one and two years of age.
This is SO mean-spirited. Think about all those poor hispanic women who timed their pregnancies so that they'd drop their litter of anchor babies in the first few weeks after arriving in the U.S. Their plans are foiled now that they're forced to stay in Tijuana. This isn't very welcoming of us.