This reminds me that I was once attacked by a dog. I worked in the Oregon State Parks and was collecting from campers one evening. I knocked on the door of a motor home and when the owner opened it his Irish Setter came flying out at me.

I carried a clipboard which I held out in defense and he clasped his jaws on it and we danced around the campsite while he bit the clipboard and I undiplomatically instructed his owner to get control of him.

So I think carrying something (in addition to pepper spray) would be wise. Something the dog can clasp onto other than a limb.