Although that may conflict with part of the Koran:

252.When you set your dog (for the chase), mention the name of Allah, if he catches the game, and you reach it while it is still alive, cuts, its throat.
(Bukhari, Muslim).
(The Lawful and Prohibited in Islam (arb: Al Halal Wal Haram Fil Islam) by. Yusuf Qaradawi).

253.If you send your dog after the game, and it eats part of it, you should not eat of it, for the dog has hunted for itself and not for you; but if you send the dog and it kills the game without eating it, you can eat it, as it has caught it for its master.
(Ahmad, Bukhari, Muslim).
(The Lawful and Prohibited in Islam (arb: Al Halal Wal Haram Fil Islam) by. Yusuf Qaradawi).

There there's this:

Bukhari vol. IV, nos. 539 Narrated Abu Talha: The Prophet said, "Angels do not enter a house which has either a dog or a picture in it.

Bukhari vol. IV, no. 540 Narrated Abdullah bib Umar: Allah’s Apostle ordered that the dogs should be killed.

Muslim vol. I, no. 551 Ibn Mughaffal reported: The Messenger of Allah ordered killing of the dogs, and then said: "What about them, i.e. other dogs?" and then granted concession to keep the dog for hunting and the dog for the herd and said: "When the dog licks the utensil, wash it seven times and rub it with dirt the eighth time."

Muslim vol. I, no. 552 A hadith like this has been narrated from Shu’ba with the same chain of transmitters except for the fact that in the hadith transmitted by Yahya those words are: "He (the Holy Prophet) gave concession in the case of the dog for looking after the herd, for hunting and for watching the cultivated land," and there is no mention of this addition (i.e. concession in case of watching the cultivated lands) except in the hadith transmitted by Yahya.

Footnote # 486 The dog is one of the unclean beasts according to Islam and eating its flesh is forbidden and its keeping in the house as a pet is also prohibited for the Muslims. They have, however, been permitted to keep dogs for hunting, herding and watching.

Chapter DCXVIII

THE PRICE OF A DOG...AND THE SELLING OF A CAT FORBIDDEN:

Muslim vol. III, no. 3803 Abu Mas’ud al-Ansari reported that Allah’s Messenger forbade the charging of price of the dog.

Muslim vol. III, no. 3806 Khadji reported Allah’s Messenger as saying: "The price of a dog is evil."

Muslim vol. III, no. 3808 Abu Zubair said: I asked Jabir about the price of a dog and a cat; he said, "Allah’s Messenger disapproved of that."

Muslim vol. III, no. 3809 Ibn ‘Umar reported Allah’s Messenger giving command for killing dogs.

Muslim vol. III , no. 3810 Ibn ‘Umar reported: Allah’s Messenger ordered us to kill dogs and he sent men to the corners of Medina that they (i.e. the dogs) should be killed.

Muslim vol. III, no. 3813 Abu Zubair heard Jabir b. Abdullah saying: Allah’s Messenger ordered us to kill dogs and we carried out this order so much that we also killed the dog coming with a woman from the desert... He said, "It is your duty to kill the jet-black dog having two spots, for it is the devil."

(See also Muslim vol. III, nos. 3814-3829)