Turn the aerator housing counterclockwise and remove it from the faucet. Pull the O-ring off the tip of the faucet spout with your finger. The O-ring prevents leaking between the housing and the faucet. Set the O-ring in a safe place until you are ready to reinstall the housing.
After that, they are referred to as yearlings or stirks if between one and two years of age. A castrated male is called a steer in the United States; older steers are often called bullocks in other parts of the world but in North America this term refers to a young bull.
In the terminology used to describe the sex and age of cattle, the male is first a bull calf and if left intact becomes a bull; if castrated he becomes a steer and in about two or three years grows to an ox. The female is first a heifer calf, growing into a heifer and becoming a cow.