Musnad Ahmad 28:561

Mu'ammal narrated to us, Wuhayb narrated to us, Ibn Tawus narrated to us, from 'Amr ibn Shu'ayb, from his father, from his grandfather, who said: "The Messenger of Allah (peace and blessings of Allah be upon him) forbade the meat of domesticated donkeys, and [he forbade] the *jallalah* (animal that feeds on filth), and [he forbade] riding it and eating its meat."