Farriers are not allowed to float teeth on horses nor to give sedation shots to horses. Even if a farrier knows how to float horse's teeth, it is not a good idea to do it as it's illegal in many states to practice veterinary medicine unless board certified. Floating teeth is a veterinary job and requires a veterinary degree.  The practice of floating teeth was originally developed by veterinarians. As early as 1879, the American Veterinary Medical Association adopted the practice as a standard of care.