I'm pretty sure that picking up your dog is a mistake, and in many cases will result in a bite either to him or you. (It would probably be my first reaction as well though! <img src="/images/graemlins/grin.gif" alt="" />) Doing so reduces your mobility as well as negating any chance of using your arms to defend yourself. Perhaps, if legal, take a stout walking stick and/or some pepper spray along when you walk him. Much better than a knife, which should be a last ditch weapon at best. Oh, and buy two pepper sprays and practice with one!