Musnad Abu Ya'la al-Mawsili 42:42

'Abd al-A'la narrated to us, Hammad narrated to us, from al-Hajjaj, from 'Atiyyah, from Abu Sa'id, that a man asked the Messenger of Allah (may Allah bless him and grant him peace) about a sheep whose tail a wolf had cut off: "May I offer it as a sacrifice?" He said: "Yes, offer it as a sacrifice."