The Bodhisatta. was once an ox named Mahālohita and his brother was Cullalohita. They both belonged to a village family, and when the girl of the family grew up and was married, a pig, called Sālūka, was fattened for the feast. Cullalohita, saw this and coveted the food which was being given to the pig, but when he complained to his brother, it was explained to him that the pig's lot was an unhappy one.
The introductory story is given in the Culla Nāradakassapa Jātaka. Sālūka is identified with the love sick monk of that story, and Cullalohita with Ananda. J.ii.419f.