My views on this topic are quite similar to the preceding posts. If there are wild dogs present in your hunting area, not only do they pose a serious threat to your deer heard, they also pose a threat towards you, and that's reason enough to go to extraordinary lengths to take care of such a crucially problematic situation. By all means, I'm not suggesting that you takeout every dog within a 5 mile radius, but if you see an unfamiliar dog, then I would suggest you be cautious. As the posts above stated, check with the surrounding property owners to see that they keep their dogs on their own properties.
Conserving energy is crucial for deer during the cold winter months, and if there are free-roaming wild dogs on your property there is a good chance that you may be missing a few deer from your heard the following year. Older bucks that are depleted of strength and energy from the rut, and fawns are the two most common victims of wild dogs. And if this continuously occurs, it may potentially unravel any deer management you have done to better the heard. And not only do they pose a physical threat to the deer and the other wildlife in the area, as Shredder mentioned, many of these dogs are rabid and often carry diseases.
Unfortunately, I've experienced the threat that wild dogs possess firsthand. Last year while tracking my deer, I came across a group of wild dogs that had made a den in some thick brush on our property. As I was following the blood trail, I was completely unaware that I was being watched until I heard their low, eerie growls directly in front of me. My first instinct was to hightail it out of their, but as fate would have the brush was much to thick to make a quick get away. So I grabbed a fairly large branch and managed to hit the largest dog across the face, before they dispersed. Further observation revealed that they had been feeding on a doe. Although I wasn't able to get a shot at them, if one does decide to pass my stand this fall, I will surely let an arrow fly.