Snakes and vaccines

This is not a rattlesnake, this is a harmless to humans Pacific Gopher  Snake (note the long thin tail sans rattle!)

I stepped out of my car yesterday evening I the driveway and onto something squishy (Never a good feeling!!) I had stepped on a snake warming itself on the asphalt. There was a panic moment, was it a rattler? And did it need to be dispatched? I’ve had close encounters with rattlesnakes before, and neighbours have warned me they are common in the neighbourhood. I managed to snap a photo, and the lack of a triangle head and rattle, I shooed him off into the bushes. 

But it did get me thinking about the rattlesnake vaccine, for the dogs and ponies... I know it isn’t a cure, but does buy time for the emergency trip to the vet .... has anyone had any experience with the vaccine  (good or bad)? The yard is fenced, but backs up to acres of untouched sagebrush....so there could easily be rattlers around...