i remember a lecture i once attended given by a venomous snake expert from usc, and i could possibly come up with the scientific reference for the following: statistically, a snake bite victim is a male, under the age of 25, has tattoos, is bitten on the hand or fingers, and has a blood alcohol content that would get you arrested if driving. as i recall, that's what he said.

remember, the snake will sense you by vibration but will strike at the heat it senses - it will strike at the threat with some accuracy. it'll go for your legs or higher. not your foot-level boot.

in your case, i'll make a stretch here and assume you wear pants with your cowboy boots. the snake's fangs may or may not even pierce the pant fabric - denim is pretty dense material. even if it does pierce the material, it's unlikely the fangs would then pierce your cowboy boot.

if you still have a concern, i agree that gaiters, commonly found in hiking stores, are your answer. impenetrable. and they go on and come off easily.

in my case, the snakes have all seen me and let me know about it by making noise before i ever saw them. and that's how i learned to fly. but that's another story.