From Sahih Bukhari (Hadith 5547):
Narrated `Uqba bin 'Amir Al-Juhani:that the Prophet (ﷺ) distributed among his companions some animals for sacrifice (to be slaughtered on `Id-al-Adha). `Uqba's share was a Jadha'a (a six month old goat). `Uqba said, "O Allah's Messenger (ﷺ)! I get in my share of Jadha'a (a six month old ram)." The Prophet (ﷺ) said, "Slaughter it as a sacrifice
Reference: Bukhari 5547