The Book of Hunting and Slaughtering
42/29. Chapter:
Permission To Eat Horse Meat
Sunan an-Nasai
أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا سُفْيَانُ، عَنْ عَمْرٍو، عَنْ جَابِرٍ، قَالَ أَطْعَمَنَا رَسُولُ اللَّهِ صلى الله عليه وسلم لُحُومَ الْخَيْلِ وَنَهَانَا عَنْ لُحُومِ الْحُمُرِ .
It was narrated that Jabir said: "The Messenger of Allah allowed us to eat the flesh of horses but he forbade the flesh of donkeys."
Reference : Sunan an-Nasa'i 4328In-book reference : Book 42, Hadith 66English translation : Vol. 5, Book 42, Hadith 4333