A public interest group is suing the Minnesota Board of Veterinary Medicine on behalf of a plaintiff the group claims has been denied his constitutional rights to earn a living filing down horses' teeth.

The Minnesota Chapter of the Institute for Justice filed its suit Aug. 16 in the First Judicial District Court on behalf of Chris Johnson of Hutchinson, Minn., a third-generation horse teeth floater who is not a veterinarian.

Johnson had floated the teeth of about 500 horses during a six-month period in 2004 until the veterinary board warned him he could face prosecution for practicing veterinary medicine without a license, according to the lawsuit.

Minnesota's Veterinary Practice Act was amended the next year to designate licensed veterinarians, laypersons with more than 10 years of floating experience, and laypersons certified by the International Association of Equine Dentistry as authorized to float horse teeth.

The Institute for Justice said the conditions placed on Johnson are unreasonable, and characterized the law as "anti-competitive" and a monopoly on "the most trivial areas of animal care."

The triviality of floating horse teeth is open for debate, however. Resistant horses oftentimes need to be tranquilized, for example. Or, broken teeth, lacerations, and other complications resulting from floating could require immediate veterinary care.

According to the AVMA State Legislative and Regulatory Affairs Department, 13 states make exemptions for nonveterinarians to float horses' teeth: Arizona, Connecticut, Florida, Idaho, Illinois, Louisiana, Maryland, Minnesota, New York, Oregon, Pennsylvania, South Carolina, and Vermont.

AVMA policy states that dentistry on animals is part of the practice of veterinary medicine and should be performed by veterinarians in accordance with their state veterinary practice acts.