Yahya related to me from Yahya ibn Said from Muhammad ibn Ibrahimibn alHarith at-Taymi from Rabia ibn Abi Abdullah ibn alHudayr that hesaw Umar ibn al-Khattab taking the ticks off a camel of his at as-Suqya while he was in ihram .Malik said that he disapprovedof that.
USC-MSA web (English) reference: Book 20, Hadith 93
Arabic reference: Book 20, Hadith 795