Excellent advice here....really.
John,
First time I was alone with my dog. It probably looked comical but when this dog went after mine I picked my dog up, by the short leash, and tried to suspend him above the attacking dog and beat him away with my foot and free arm. I tried to keep myself between the two. in spite of my effort a couple of pucture wounds were found later.
Rick, I love shepards ...well except for this frustrated one
A talk is in order as this animal is a menace. The invisible fence is a great idea but I've heard out of control dogs ignore the collar when they're fired up.
A 357 wouldn't be my solution but something more of pick-up and slam to the ground or tree or....? But I really don't want to resort to that.