I find tea tree oil in surgical spirit is good too.
I pour the small (15ml?) bottle of pure tea tree oil you can buy into 200ml of surgical spirit. Cures all sorts of sore skin things on sheep, me, dogs.....
I also use it when I tag ears, pour onto the holes/posts after tagging and have never had an infection since I started doing it.
I expect it stings a bit but they don't seem to mind too much.