Sahih Muslim — The Book of the Merits of the Companions — Hadith No: 6248

Sulaiman Shaibini reported:I heard Abdullah b. Abu Aufa say: We were smitten with hunger during the nights of Khaibar. On the Day of Khaibar, we fell upon domestic asses and we slaughtered them, and when our earthen pots boiled with them, the announcer of Allah's Messenger (ﷺ) made an annoancement that the earthen pots should be turned over, and nothing should be eaten of the flesh of the domestic asses. Some of the people said that Allah's Messenger (ﷺ) had forbidden (the use of this flesh) for one-fifth (due to the State) has not been paid, while others said: He prohibited it for ever

Bara' b. 'Azib reported:Allah's Messenger (ﷺ) commanded us to throw away the flesh of domestic asses whether uncooked or cooked; he then never commanded us to eat that

Al-Bara' said:We found on the Day of Khaibar domestic asses, and the announcer of the Messenger of Allah (ﷺ) made an announcement that the earthen pots should be turned over

Jabir b. 'Abdullah reported that Allah's Messenger (ﷺ) prohibited eating of the flesh of domestic asses on the Day of Khaibar, and permitted the cooking of the flesh of horses