The Book of Musaqah
حَدَّثَنَا مُحَمَّدُ بْنُ الْمُثَنَّى، وَابْنُ، بَشَّارٍ - وَاللَّفْظُ لاِبْنِ الْمُثَنَّى - قَالاَ حَدَّثَنَا مُحَمَّدُ، بْنُ جَعْفَرٍ حَدَّثَنَا شُعْبَةُ، عَنْ قَتَادَةَ، عَنْ أَبِي الْحَكَمِ، قَالَ سَمِعْتُ ابْنَ عُمَرَ، يُحَدِّثُ عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " مَنِ اتَّخَذَ كَلْبًا إِلاَّ كَلْبَ زَرْعٍ أَوْ غَنَمٍ أَوْ صَيْدٍ يَنْقُصُ مِنْ أَجْرِهِ كُلَّ يَوْمٍ قِيرَاطٌ " .Ibn Umar (Allah be pleased with them) narrated Allah's Messenger (ﷺ) as saying:He who kept a dog ther than one meant for watching the fields or herds or hunting would lose one qirat every day out of his reward (with God)
From Sahih Muslim, whose reports the scholars accept as authentic.