The Japanese word for "Bullock" is kyoseigyuu 去勢牛.
- A male Cow, Cattle, that has not been castrated is called a Bull. A castrated male cattle is called a Steer. An older Steer is called a Bullock, but in North America a Bullock is a young Bull. An Ox is Cattle kept for draft or riding. Oxen are often Steers. A Steer is called kyoseigyuu 去勢牛 in Japanese. If the Ox isn't a Steer, then he's called the same as a Bull in Japanese, oushi 牡牛.
Beware: some kanji that are difficult to handwrite are easy to type on the computer, which may skew the usage statistics.