Sunan an-Nasa'i, Volume 5, Book 43, Hadith 4426 (DarusSalam) ⓘ
It was narrated that Asma said: "We slaughtered (naharna) a horse during the time of the Messenger of Allah while we were in Al-Madinah, and we ate it." (Sahih )
أَخْبَرَنِي مُحَمَّدُ بْنُ آدَمَ، قَالَ حَدَّثَنَا عَبْدَةُ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ فَاطِمَةَ، عَنْ أَسْمَاءَ، قَالَتْ ذَبَحْنَا عَلَى عَهْدِ رَسُولِ اللَّهِ صلى الله عليه وسلم فَرَسًا وَنَحْنُ بِالْمَدِينَةِ فَأَكَلْنَاهُ .
also referenced under: Hadith 4421 (Reference) & Book 43, Hadith 61 (In-Book)