Abu Dawud Book 9, Hadith Number 2792.
Chapter : On the age of the sacrificial animal.
Narated By Zayd ibn Khalid al-Juhani : The Apostle of Allah (PBUH) distributed sacrificial animals among his Companions. He gave me a kid (of less than a year). I took it to him and said: This is a kid. He said: Sacrifice it. so I sacrificed it.