On the day of Khaybar, the Messenger of Allah ﷺ forbade the eating of donkey meat and permitted the eating of horse meat.
أخبرنا قتيبة وأحمد بن عبدة قالا حدثنا حماد عن عمرو وهو ابن دينار عن محمد بن علي
نهى وذكر رسول الله ﷺ يوم خيبر عن لحوم الحمر وأذن في الخيل
Reported by Muslim in Sayd wa Dhabaih, chapter on the permissibility of eating horse meat, no. 1941, from Qutayba, and by Bukhari in Maghazi, chapter on the Battle of Khaybar, no. 4219, and nos. 5520, 5524, from the hadith of Hammad bin Zayd through this same chain. It is also found in Kubra, no. 4839.