It was narrated that Ibn 'Umar said:

"The Messenger of Allah said:' whoever keeps a dog except one that is trained for hunting or a dog for herding livestock, two
Qirats will be deducted from his reward each day."

أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا اللَّيْثُ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، أَنَّهُ سَمِعَهُ يَقُولُ إِنَّ رَسُولَ اللَّهِ ﷺ قَالَ " مَنْ أَمْسَكَ كَلْبًا إِلاَّ كَلْبًا ضَارِيًا أَوْ كَلْبَ مَاشِيَةٍ نَقَصَ مِنْ أَجْرِهِ كُلَّ يَوْمٍ قِيرَاطَانِ " .