I recall someone telling me to use straight vinegar
or amonia in a squirt gun.
My neighbor was attacked by a dog while riding. The
dog attacked up front first, then round round back & jumped on the rump.
Neighbor ended up with fractured skull, bad concussion, 7 broken ribs, in
intensive care for over a week. The dog owner did have him in a fence, but the
dog jumped out, it was the first time. The insurance co paid, but made them make
the fence higher.