Oxen were beasts of burden commonly used on Earth. Cameron Campbell once travelled in rural India and was disturbed by the fact he couldn't see even one skinny ox pulling farmers around in a cart. (PROSE: Ghosts of India)
Oxen were found in Kiev in 1240. (PROSE: Bunker Soldiers)
The Thirteenth Doctor sent Graham O'Brien to collect the spit from an ox. (TV: Demons of the Punjab)
The First Doctor used an example of having three oxen and a box which travels through space in a description of Chinese whispers to a group of 1st century Christians. (PROSE: Byzantium!)