After encountering multiple rattlesnakes in the course of 7 days, we decided to do rattlesnake aversion training with our dog.
It was pretty quick, on the order of 15 minutes and looked to be pretty effective. They use a shock collar, starting on a low setting. Mr. Atlatl had the trainers shock him at several levels before the collar went on the dog.
All the snakes were humanely muzzled.
They started with a baby snake, and it took a single zap for our dog to decide he wanted nothing to do with it. He correctly responded then to a shed skin, a rattle (from a snake) and an adult snake. He got some reinforcement at each of the subsequent items. The handler was great about petting and praising him along the way.
The final test was when we got to call him to us with the adult snake in between us and the dog; he took the scenic route to us, dragging the handler so as to give the snake a wide berth.
This is the company we used, I highly recommend them.