The Bodhisatta was once an ox, called Mahālohita, in a householder's family, where his brother Cullalohita and he did all the work. When their master's daughter was about to be married, a pig, named Munika, was brought and fattened on all kinds of luxuries. Cullalohita protested to his brother, but the latter warned him of Munika's fate. And soon after Munika was killed and eaten.
The origin of the story is the same as that of the Culla Nāradakassapa Jātaka. The passion-tost monk was Munika, and Ananda the younger ox. J.i.196ff.