The Prophet ﷺ said, "Whoever keeps a dog, except a dog for guarding crops, livestock, or for hunting, his reward decreases by one qirat each day."
حدثنا محمد حدثنا شعبة عن قتادة عن أبي الحكم سمعت
عن النبي ﷺ قال من اتخذ كلبا إلا كلب زرع أو غنم أو صيد فإنه ينقص من أجره كل يوم قيراط
Its isnad is sahih. Abu Hakam is Bajali Abdul-Rahman bin Abu Naeem. The hadith is an abridgment of 4813 through his route, and its meaning has already occurred through other routes many times, the last of them being 5393.