DayZ creator Dean "Rocket" Hall has been showing IGN his plans to bring dogs to DayZ. They'll act as faithful companions that can track down animals and, eventually, will defend you from zombie attacks. The German Shepherd can be given orders, but the extent to which he'll follow them depends on how experienced he is. A young dog will wander around trying to find you after 30 seconds if he's not well trained.
Of course, owning a dog brings with it the possibility of losing your chum to the zombie hordes. That's a harrowing thought. I love dogs, even virtual ones that sit so still it looks as though they've died and been replaced by a stiff taxidermy replica. Their addition to DayZ will surely make the entire experience that much more fraught. See an early build of the dog update in action in this very video.
The DayZ Arma 2 mod is being updated alongside development of the standalone version of DayZ announced earlier in the month. Evan had a chat with Dean Hall recently about the future of DayZ , we can look forward to much more than dogs.