Guard dog

The second question of Fatwa no. 7900 What is the ruling on having a dog at home only for guarding the house? What is the part in the body of the dog which is Najis (ritually impure)? Is it the saliva or its whole body? Should a Muslim perform Wudu' (ablution) if he touches a dog or not?

A: It is permissible to keep dogs to guard a house, sheep, or farms. It is authentically reported that the Prophet (peace be upon him) stated: Whoever keeps a dog except a dog for herding, hunting, (Part No. 22; Page No. 509) or farming, one qiraat will be deducted from his reward each day. Related by Al-Bukhari and Muslim A Muslim does not need to perform Wudu' if he touches a dog, because touching it is not a nullifier of Wudu'. However, all the dog is impure including its saliva and other parts.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.