Musnad Ahmad 627:12

Muhammad ibn Ja‘far narrated to us, Shu‘bah narrated to us, from Sa‘id ibn Masruq, who said: Al-Sha‘bi narrated to us, who said: I heard ‘Adi ibn Hatim—and he was our neighbor, or an associate, or a resident in Al-Nahrayn—that he asked the Prophet, peace and blessings of Allah be upon him, and said: "I send my dog, and I find with my dog another dog that has caught [the game], and I do not know which of the two caught it." He said: "Do not eat, for you only pronounced the name of Allah over your dog, and you did not pronounce it over the other."