Sahih Muslim
The Book of Games and the Animals which May be Slaughtered and the Aninals that Are to be Eaten (Kitab-us-Said wal-Dhabaih wa ma Yukalu min Al-Hayawan)
Book Number: 021 / Hadith Number: 4763
'Ali b. Abi Talib reported that Allah's Messenger (may peace be upon him) forbade on the Day of Khaibar temporary marriage (Muta') with women and the eating of the flesh of domestic asses.