The Prophet (may Allah's peace and blessings be upon him) forbade eating the flesh of domestic donkeys and permitted that of horses.

Jābir ibn ‘Abdullāh (may Allah be pleased with him) reported: The Prophet (may Allah's peace and blessings be upon him) forbade eating the flesh of domestic donkeys, and permitted eating horseflesh.
Muslim's narration reads: "We ate horse meat and wild donkeys during the time of Khaybar, but the Prophet (may Allah's peace and blessings be upon him) forbade us from eating the flesh of domestic donkeys."
‘Abdullāh ibn Abu Awfa (may Allah be pleased with him) reported: We were afflicted with severe hunger during the nights of Khaybar. On the day of the battle of Khaybar, we came across some domestic donkeys and we slaughtered them. While being cooked in the pots, the Prophet's announcer called that the pots should be turned over - and perhaps he said: "And eat nothing of the donkeys' flesh."
Abu Tha‘labah (may Allah be pleased with him) reported: The Messenger of Allah (may Allah's peace and blessings be upon him) prohibited eating the meat of domestic donkeys.