Hurmat Vs Fitrat
The cause of the prohibition is not explicit in the incident. Narrated Ibn Abi Aufa: We were afflicted with hunger during the besiege of Khaibar, and when it was the day of (the battle of) Khaibar, we slaughtered the donkeys and when the pots got boiling (with their meat). Allah's Apostle made an announcement that all the pots should be upset and that nobody should eat anything of the meat of the donkeys. We thought that the Prophet prohibited that because the Khumus had not been taken out of the booty (i.e. donkeys); other people said, "He prohibited eating them forever." The sub-narrator added, "I asked Sa id bin Jubair who said, ‘He has made the eating of donkeys’ meat illegal for ever.”) (Bukhari 3155)