I think a walking stick would serve the purpose. 95% of the population will not recognise a walking stick as a weapon, while 5% will realize it is a quarter staff, more or less. It has the advantage of reach, adds power to your hit, can be used to keep the animal away from you (bite range), and if you have to, it can kill a dog rather easily.

I had a run in with a neighbor's dog. I got 29 stitches and a really neat scar on my right calf. The dog was buried. Privately the neighbor thanked me, son's dog, but son didn't want it around his young child as it was a biter. No kidding.

Since that day I am vigilant around dogs of any size. I like dogs, I just realize they are not all friendly puppies.