So many good ideas
Pellet guns work wonders :)
I don't know if my parents would let me, but this definitely would work :)
@Fiinx: Me too... I lost some amazing trails just because of the stupid dogs.
I didn't try chasing the dog, but I'll try next time. :) Dogs, here we come! Beware!
When my dog was still able to go to trails with us (he is dead now, because of the age - he couldn't walk in the end :( ) he made all dogs ran away. There was a problem only once, when some dog didn't want to leave and they got into a fight... Thank god, he wasn't injured, but it didn't keep my horse calm either :P
A squirt bottle (think travel sized from walmart) with water alone will scare them. Filled with white vinegar, the dog owner will think twice before they let the dog come close to you again. If you are riding on a public road or on your own private property, I highly suggest this route. No one gets hurt and the owners usually get the point when their dog comes in reeking like vinegar.
I will definitely do this! I think this will help a lot!