Sunan Ibn Majah
3204
Sahih+3

It was narrated that Abu Hurairah said:“The Messenger of Allah (ﷺ) said: ‘Whoever keeps a dog, one Qirat will be deducted from him (good) deeds every day, except a dog for farming or herding livestock.”

SahihAl-Albani
SahihMuhammad Fouad Abd al-Baqi