By personal experience don't bother with any spray marked for dogs, it is too weak. You will have to get bear spray. Unfortunately I have had to use it on a dog, and it did stop. It did not seem to bother it much though. I also have used the repeal for dogs, didn't do much but the dog stopped just as it ran out, and seemed to laugh at me.
Chuck, Cooper and Nina
Shelter dogs aren't broken. They've simply experienced more life than other dogs. If they were human, we would call them wise. They would be the ones with tales to tell and stories to write. Do not pity a shelter dog. Adopt one.