Genetic Defects Statement Issued by AAEP

The American Veterinary Medical Association (AVMA) recently re-stated a policy that surgical correction of “genetic defects” for the purposes of concealing the defect is unethical. If surgical correction is undertaken for the purpose of improving the health of the individual, then it should be accompanied by sterilization to prevent the perpetuation of the genetic flaw.

The American Association of Equine Practitioners (AAEP) agrees with the intent of this position. In their communications the AVMA specifically mentions the substitution of prosthetic testicles for natural testicles in cryptorchid dogs. There is no doubt that this type of procedure is fraudulent in that the prosthetic substitute is a non-functional substitute for a body organ with a normal physiologic function and is aimed at deceptively representing that the dog has normal testicles. The AAEP concurs that this type of surgery is equally fraudulent in horses and is to be condemned as a surgical procedure intended only to deceive, not to treat. The procedure is of no benefit to the horse.

Genetic Defect

The AVMA statement refers specifically to correction of genetic defects. By definition genetic defects are a pathologic condition of proven genetic origin. The gene responsible for inheritance is known for only three genetic defects in the horse: hyperkalemic periodic paralysis in the Quarter Horse, lethal white syndrome in the Paint Horse and combined immunodeficiency in Arabian horses.(1) If these diseases were correctable surgically, which they currently are not, their correction should be accompanied by sterilization.

Congenital Defect

All undesirable traits and pathologic conditions present at birth were at one time thought to be entirely genetic in origin. Present-day knowledge has evolved to the point that we now know that many, if not most, congenital defects are the result of intra-uterine events that results from extra-uterine influences. Viruses and toxins are well documented to cause congenital defects(2,3). Certain conditions that were previously thought to be genetic are now suspected, with good evidence, to be created by viral or toxic insults. Contracted flexor tendons in newborn foals have been proven to be created by toxic influences in some instances.(4) Arthrogryposis and cerebellar hypoplasia, are other diseases that have suspected infectious or toxic causes because this link has been proven in other species.(2,3) Congenital defects do not indicate inheritance; they simply indicate that the defect was present at birth.

Inherited Tendencies

There are characteristics in horses that are genetically influenced. Horses have been selectively bred for centuries to promote or discourage these characteristics. The selection for or against these inherited tendencies is the basis for our current breed registries. Size, power, color, speed, conformation and many other characteristics that are genetically influenced are selected for or against by certain breed registries. Variations from ideal may be undesirable but they are not genetic defects. A variation in color is an example of an undesirable characteristic that may be named by a breed as being undesirable. Correction of this characteristic specifically named by the breed organization as being prohibited, with the purpose of concealing the characteristic for obtaining registration, would be an example of a surgical procedure that would be unethical. It has no benefit to the horse and is intended only to deceive the breed organization.

The AAEP supports surgical correction of diseases that are in the best interest of individual horses. Surgical correction of inherited defects in the horse is currently not practical for the known genetic defects. So, while the AAEP supports the intent of the AVMA statement, it should be applied to genetic defects and not misapplied to congenital defects or inherited tendencies.

1) Personal Communication, Dr. Doug Antczak, Cornell University, Baker Institute, 2002.
2) Murtaugh, Robert J. Pediatrics: The Kitten from Birth to Eight Weeks, In “The Cat”, Sherding Chirchill/Livingstone p. 1504.
3) Kahrs, RF: Viral Diseases of Cattle, Iowa State Press, 2001, p.117.
4) McIlwraith CW, James LF: Limb Deformities in Foals Associated with Ingestion of Locoweed by Mares. J Am Vet Med Assoc, 181:255-258, 1982.

About the Author

American Association of Equine Practitioners

AAEP Mission: To improve the health and welfare of the horse, to further the professional development of its members, and to provide resources and leadership for the benefit of the equine industry. More information:

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