A few weeks ago while hiking, my German Shepherd and I had a close encounter with two Rhodesian Ridgeback (aka African Lion) dogs ... I had to draw my weapon on them, but since I'm familiar with dogs I didn't shoot. These dogs showed attack behavior up until the last 10 yards (of their 100 yard sprint to us). In addition, we encounter coyotes (solo and packs of six) very often when we hike.
I recently started carrying Counter Assault Bear Spray
as my first line of defense. I emailed the company and they told me that their spray is effective to deter dogs and coyotes from continuing their attack. I've also seen bear spray used in youtube videos on attacking dogs and it appears to work. I purchased my 8 oz can at Sportsman Warehouse for about $40.