Originally Posted by Corporal
You won't be able to buy rabies if you need to give that shot without a prescription from your Vet.
I think this is a state-by-state thing. My understanding (though I'm sure at least some places have changed in the 20 years since I needed this!) is that in some states (including NH at the time) it's basically unregulated, you just order it, in others no one but a vet could get it, even with a prescription. Or maybe it's just a matter of shipping, and you can buy it locally - but the Omaha Vaccine listing says that state laws don't even allow them to ship to 30+ states. I also understood when we gave it that it gave us peace of mind, but in the unlikely event that our horse was bitten by something and the authorities became involved, legally it was as if it were unvaccinated (because we didn't have that signed paper from the vet).
At some point we had a bad experience with the only large-animal vet in the area and from then on we gave vaccines ourselves (and thank goodness never needed another vet until the day over a decade later when one of our horses colicked and died - vetless, though my mom did try to get one out
). We used the instructions from an early issue of _Equus_ magazine which showed the safe area. We were a bit squeamish - when I first brought my husband (then fiance) to my parents' house, Mom & I shoved the syringe in his hand, held up the article pictures for him to see, and had him do it from then on.