Sahih Bukhari Volume 007, Book 067, Hadith Number 417.
Narrated By Rafi bin Khadij : I said, "O Allah's Apostle! We are going to face the enemy tomorrow and we do not have knives." He said, "Hurry up (in killing the animal). If the killing tool causes blood to flow out, and if Allah's Name is mentioned, eat (of the slaughtered animal). But do not slaughter with a tooth or a nail. I will tell you why: As for the tooth, it is a bone; and as for the nail, it is the knife of Ethiopians." Then we got some camels and sheep as war booty, and one of those camels ran away, whereupon a man shot it with an arrow and stopped it. Allah's Apostle said, "Of these camels there are some which are as wild as wild beasts, so if one of them (runs away and) makes you tired, treat it in this manner."