Will your job entail long periods on your feet walking/standing, or is there deskwork involved to give your dogs a rest?
If you'll be on your feet most of the time, and need a dressier-style of shoe than running shoes, I second the 'chef shoe' recommendation - they are usually black, sensible and comfortable and your legs and back will thank you. Think Dansko
; Google "chef shoes". I wear this type of shoe as a flloor nurse.
Another option for a very comfortable shoe that looks great with khakis is Dr. Marten's. They come in laceup, slip on and clogs, many styles to choose from, black, brown...very comfy!