By Dr. David Kronfeld
-- The House of Delegates of the American Veterinary Medical Association revived a Principle of Veterinary Medical Ethics in July 2002. It states: "Performance of surgical or other procedures in all species for the purpose of concealing genetic defects in animals to be shown, raced, bred, or sold as breeding animals is unethical. However, should the health or welfare of the individual patient require correction of such genetic defects, it is recommended that the patient be rendered incapable of reproduction."
The new principle differs from a previous one only by the addition of "or other." This applies the ethical principle to virtually all modes of environmental management, including feeding, trai ning, and hoof trimming.
The principle is responsive mainly to correction of genetic defects in purebred dogs. The common example is furnishing a cryptorchid with a prosthetic testicle. Once written, however, the words may be applied to other situations.
The key word is "concealing." The correction is likely to increase the value of the animal, especially for breeding. The scabrous word is "unethical." The Greek ethikos means character or custom, and ethics relate to customs that vary between communities.
Owners and breeders must make hard decisions about their animals. They assess the advice of veterinarians, sense peer pressure, and tune into public opinion. Their veterinarians can and should provide professional advice as well as professional services. But should a vet deny a service in a way that, in effect, accuses a client of fraudulent intent? Of course, if the client admits a criminal purpose, the veterinarian's ethical problem is resolved.
The term "genetic defects" is most readily understood in regard to an inherited abnormality. Should an owner feed a low-potassium diet to a Quarter Horse endowed with the single HYPP gene? Most conditions of genetic interest in the Thoroughbred, however, are not simple and have not been established in a rigorous scientific manner. Instead, a genetic component is suspected from breeding lines and from pathophysiological considerations. Is this suggestive information sufficient for a critical decision on genetics to be made by the veterinarian? Or would it leave this individual legally vulnerable without a sound quantitative estimate of heritability or a demonstrated pattern of inheritance?
Establishing sound evidence of inheritance requires the collaboration of competing owners and breeders. Much more data on heritabilities and modes of inheritance are available on other breeds. May we infer competitive owners and breeders of Thoroughbreds have been disinclined, with rare exceptions, to participate in genetic studies destined for the scientific literature, that is, public disclosure?
Are side effects of breeding for speed "genetic defects" in the sense of the AVMA's principle? None are defects in a simple sense. Perhaps the simplest is breeding a round rump for speed and, incidentally, obtaining a sloping vulva and an increased risk of infertility. That's a risk and not a certainty, a candidate for a defect but not a defect.
Bleeding is evident from the nose or may be seen via an endoscope in the lungs. Pharmacological management with furosemide (Salix) could be concealed, but virtually all racing jurisdictions forbid the procedure and test for the drug. Does drug testing eliminate any opportunity for deception and fraud?
Periosteal stripping to straighten legs may be difficult to detect after healing. There is an opportunity for deception, so does the AVMA principle apply? This is a tough call for veterinary surgeons. Is a particular case inherited...a genetic defect? Or congenital? Or simply a sporadic happenstance?
There are suggestive observations of angular limb deformities occurring more frequently in certain faster-than-average families, but there is no rigorous scientific demonstration of inheritance. Most crooked legs correct themselves partially or completely if left untreated, and their effects on racing performance are inconsistent. In view of all this, should they be recognized as defects and, if so, are they genetic or cosmetic?
Whose ethics are ultimately responsible for the Thoroughbred horse? The owners and breeders.Dr. David Kronfeld is the Paul Mellon Distinguished Professor of Agriculture and Professor of Veterinary Medicine at the Virginia Polytechnic Institute and State University, Blacksburg.