Well I think its more so just the fact that the dogs can climb buildings, and have a 10 meter lunge range that will troll every one.
I also find that the dog's take two bursts from a MR-28 which is about 390 damage within like 20m. After one burst it usually causes them to roll meaning they won't make it to you and that alone is like 195 damage.
I'm a shotgun user, so I need to get in close for kills. If I come across a guy with a dog I go for the guy 1st to end his streak. 80% of the time the dog will get me after if it's full health.
A dog can take 3-4 shotgun blasts, but I don't cry about it. It's part of the game ... a COD game lol.
If a guy gets close, then check the mini map more or change a perk so you can hear him or his dog.
You're using a sniper rifle lol, you can kill from distance and QS in CQs. Sounds to me like you want that 'invincible' perk that doesn't let you get killed by anything, anywhere at any time lol.