Musnad Abu Ya'la al-Mawsili 153:4

Abu Khaythama narrated to us, Sufyan ibn 'Uyaynah narrated to us, from al-Zuhri, from Salim, from his father, from the Prophet (peace and blessings of Allah be upon him), who said: "Whoever acquires a dog, except for a hunting dog or a dog for livestock, two qirats from his reward decrease every day."