He heard the Messenger of Allah ﷺ say, "It is not permissible to eat the meat of horses, mules, and donkeys."
أخبرنا إسحق بن إبراهيم قال حدثنا بقية بن الوليد قال حدثني ثور بن يزيد عن صالح بن يحيى بن المقدام بن معدي كرب عن أبيه عن جده
أنه سمع رسول الله ﷺ يقول لا يحل أكل لحوم الخيل والبغال والحمير
[Its chain is daif] Abu Dawud narrated it in the Book of Foods, chapter on eating horse meat, no. 3790, and Ibn Majah, no. 3198, from the hadith of Baqiyyah with this wording. It is also found in Sunan al-Kubra, no. 4843. Musa bin Harun al-Hafiz, Bayhaqi, and others declared it daif.Salih is lenient (Taqrib), and Bukhari said of him, "There is doubt about him," and his father is obscure.