He was tending a milk-camel in one of the ravines of Uhud when she was overcome by death. Finding nothing to slaughter her with, he took a stake and stabbed it into the base of her throat until her blood flowed out. Then he came to the Prophet ﷺ and told him what had happened, and the Prophet ordered him to eat from it.
حدثنا قتيبة بن سعيد حدثنا يعقوب عن زيد بن أسلم عن عطاء بن يسار
أنه كان يرعى لقحة بشعب من شعاب أحد فأخذها الموت فلم يجد شيئا ينحرها به فأخذ وتدا فوجأ به في لبتها حتى أهريق دمها ثم جاء إلى النبي ﷺ فأخبره بذلك فأمره بأكلها
Its chain of transmission is sahih. Bayhaqi reported it in 9/250, 281 from the hadith of Abu Dawud through the same chain, and Ahmad reported it in 5/430.