From Sahih Muslim (Hadith 4019):
Ibn Umar (Allah be pleased with them) reported that Allah's Messenger (may peace be, upon him) ordered the killing of dogs except the dog tamed for hunting, or watching of the herd of sheep or other domestic animals. It was said to Ibn Umar (Allah be pleased with them) that Abu Huraira (Allah be pleased with him) talks of (exception) about the dog for watching the field, whereupon he said:Since Abu Huraira (Allah be pleased with him) possessed land
Reference: Muslim 4019