Can I hit a dog for self defense?

Yes. Absolutely. I AM a dog lover, and if a dog attacked me, I'd do whatever the hell I could to get it off me.
That being said, hitting it probably isn't the best way to stop an attack... if you're reaching out with your arms to hit it, you're exposing your belly and throat.
Try speaking to the owners about your concerns, and ask that they keep the dog under control and/or confined. Stress that although you';re not going to be contacting anyone YET, they could be in serious trouble by allowing this to happen. If you aren't satisfied with the response you get from them, or if they continue to allow the dog to attack, you have every right to call animal control.

If you are being attacked by a dog, yes you can hit it all you want however, when a dog is in what they call the "Red Zone" enough to attack then they feel no pain what so ever. Chances are when it's attacking you won't be able to hit it. If a dog runs at you, do not run, this makes the dog chase even more, simply stand straight up, cross your arms and do not make eye contact. Your demeanor tells the dog you mean business it's the body language that tells the dog to back off. Another method is if you are being attached you pull yourself into a tiny ball as tight as you can and you yelp like a wounded puppy, it might take a few minutes for this to register but a dog is more likely to back off than if you are fighting it.

If this dog is getting loose and is attacking people then it should be reported to animal control, no dog should be running around loose especially if it's a menace to society.

if the dog is actually trying to bite you, yes, you can do anything necessary out of self defense.

If the dog does bite.. I highly reccommend that you go to the hospital, get it treated (your neighbor is responsible for the medical bills, and you can take him to small claims if he refuses to pay).. DO report the bite! If a dog is allowed to roam loose and is attacking and biting, then the bites should be reported.

If you see the dog loose, call animal control and report that there is a dangerous dog at large. There's no reason why your neighbors should allow their dog to roam freely like that.

You are allowed to hit a dog if it attacks you, but other than that, no. Don't kill it, and remember dogs are very friendly creatures!

You may generally use reasonable force necessary for self-defense under circumstances where you have a reasonable belief that you are in imminent jeopardy of bodily harm. If there are multiple attackers, reasonable force might include shooting as many of them as you can. You just have to make sure that YOU are not the one starting anything, as those deaths would be manslaughter or murder (as ridiculous as that may sound). Idiots like these are the reason the national "gun death" statistics show so many "juveniles" being killed, since that number includes many that deserve to be dead for one reason or another.

Well if a person was trying to attack you, you would hit them would'nt you? its not much difference if its a dog attacking.

I don't think you can chase the dog down with a gun or a shovel (might be talking public endangerment), but you can do whatever is necessary to keep yourself safe when the dog attacks you.

If you think it will attack you again, call animal control. No sense in letting it get to that point. If it does attack you again, you are able to use lethal force to defend yourself IF it is off the owners property. If you are on the owner's property, you are a trespasser.

If it's in self-defense

First choice is stop and stand up straight and be a tree. Most dogs don't attack they put on a show. Also turn a bit so you are not staring at the dog. As for hitting well I would rather you just tried to grab and control the dog by the scruff of the neck or collar. If that is not an option then a kick usually works.

Since this is a neighbours dog really best option is talk with the neighbour and discuss how to keep the dog under control or how to make the dog get to know you and not scare you. You can do things like go over and treat the dog walk the dog and play with the dog.

My back neighbour used to have three dogs and they used to bark at me every time I went in the yard so instead of fighting with my neighbour I work with her and her dogs and trained them in about three days and about six sessions just with some cheap dog treats. I basically fed a treat to the dog that stopped barking and then I added a sit and no barking. I never said anything to them I just stood still and tossed a treat to the dog that was quiet first and then next and soon the third dog figured out if he was quiet he would get a treat.

You can, but your gonna piss it off. Especially if it wasn't attacking you. I don't mean to question what your saying, but I highly doubt that it was. My old dog got out a couple of times. She was just an escape artist. The dog getting out doesn't make them bad owners either BTW. If you own dogs over your lifetime, and other owners should back me on this, once and a while they escape. Sometimes, you might get one that's particularly good at it. This doesn't alieviate the owner's responsibility however. They are still to blame. If the dog was attacking, you woulda gotten bitten. It might have just walked up to see what you were doing. When you became aware of it's presence, you probably turned quickly if it was behind you or froze in fear if it was coming towards you. Your reactions might have put the dog off as well. My grumpy old neighbor is a dog HATER! My dog walked up behind him to see what he was up to. He was tending his garden. She was there a couple seconds just observing. When he noticed her, he freaked and swung at her. She shouldn't have been off her lead so it was my fault, but after that, she bit him and though she didn't break skin through his shirt, he had a nasty bruise. Took his whole tricept in her mouth. I would have too if I were her. Moral, make sure the dog is actually attacking otherwise its gonna be pissed. ++again, I know it was my fault, I offered to pay any expenses as a result. He just grumbled and went inside. Before it happened I was working in the yard, so I was out there and turned in time to see it happen. As soon as I yelled at her after it began, she let go and ran to our back door. She knew I was pissed at her. She was a long haired shepherd. Great dog except for that.