The name for a female donkey is a Jenny or a Jennet, the male is called a Jack and the young are called Foals.

A donkey is typically called an Ass in the USA but rarely in the UK. This name derives from the species scientific name Equus asinus asinus.

A combination of the words Jack and Ass results in the word Jackass which is used to denote stupidity in a human more frequently than as a referece to a male member of the donkey species.

It may be argued that the perseverence of the word Ass in England is almost entirely down to it's comedic synonym 'Ass' meaning a person's bottom.