Yahya related to me from Malik from Abdullah ibn Dinar that heused to see Abdullah ibn Umar sacrificing animals two at a time duringhajj and one at a time during umra. He said, "I saw him sacrifice ananimal during an umra outside the house of Khalid ibn Usayd, where hewas staying. I saw him stick his spear in the throat of the animal hewas going to sacrifice until the spear came out under its shoulder."'
USC-MSA web (English) reference: Book 20, Hadith 141
Arabic reference: Book 20, Hadith 844