Usually a female under three years of age is called a heifer. A heiferette is a young cow that has not had more than one calf. The steer is a male animal that has been castrated early before he reached his sexual maturity. The bull is an uncastrated male of any age. The stag is a male animal that has been castrated after he was a mature bull.
Cattle are always classified according to their age.
They are called calves until one year of age, from one to two they are yearlings, and over eighteen months they are short-yearlings. Long-yearlings are cattle over eighteen months but less than two years, two year olds are between two and three years and cattle three or more years are seldom considered except in the feeder trade, except for stags, bulls and cows. Steers and heifers are light, medium and heavy, and there is no weight classifications for stage, bulls or cows. The age of the animal will determine weight. It depends on the frame of the individual cow as to the classifications also.