It is narrated from Bushayr bin Yasar (may Allah have mercy on him) that Sayyiduna Abu Burdah bin Niyar (may Allah be pleased with him) offered his sacrifice before the Messenger of Allah (peace and blessings be upon him) had prayed. He said: Then I asked the Messenger of Allah (peace and blessings be upon him); I said: I took my sacrificial animal out to the prayer ground and slaughtered it before the prayer. The Messenger of Allah (peace and blessings be upon him) said: "Offer another sacrifice in its place." I looked for a goat but could not find one, so the Messenger of Allah (peace and blessings be upon him) ordered me to sacrifice a one-year-old lamb.
Hadith Referenceالمعجم الكبير للطبراني / باب الهاء / 18728