I'm no expert, but I've dealt with plenty of amatuer guard dogs, and a few professinals ones (they have business cards and a union).
The average dog I've seen is someone who's just conditioned their average dog to be a mean little bastard or gives 'em little love and attention so they're not as friendly as American type dogs (which are pampered IMO).
I saw some guys take a cat in a carrier, and let the cat out where the dogs where. Soon as the cat was running, the dogs followed, and they went into the house. Don't know what happened to the cat, but the dogs were back the next day.
This one local warlord (if you will) had these mean ass mutts that he'd feed scraps, so they were always hungry............BUT..........they'd eat the food and watch you. If you moved, they stopped eating and went on guard and would charge you if you got to close to the house/compound.
The trick with those dogs? They loved to play catch. One of the guys spent about two weeks getting the dogs used to him, tossing things ...balls, sticks, food, etc. One day during a big raid, he tossed the dogs a gernade, they caught it and ran off. You can image what happened next. He made sure to marinate the gernade overnight in some food I think.
Some of the dogs we've meet don't bark english......and didn't respond to commands in english. Though, sometimes it's the tone of the voice that will make 'em respond. SIT! With street tough dogs, sometimes a strong verbal prescene will back 'em off.
As for shooting them........lots of the guys won't shoot 'em, even if they think the dog deserves it..........mainly because it'll indicate thier position.
A few of the MPs have carried vinger or ammona in spritz bottles if they know they're going into a bad area with dog packs. Spritz spritz in the muzzles. It's a deterrent.
One trick another gal had was that she found a dog is sesson and used it to lure the street dogs away from the house we needed to go into.
It's easy getting in.........sometimes the getting out part is tougher.