January 6, 2017 Letter from Jerold S Bell, DVM, Adjunct Professor of Genetics, Cummings School of Veterinary Medicine, Tufts University Member, Hereditary Diseases Committee, World Small Animal Veterinary Association, Member, AKC Health & Welfare Advisory Panel, Member, Board of Directors, OFA
The following is what I sent to the AVMA delegate body regarding the proposed AVMA resolution:
The AVMA resolution is a welcome addition to the conversation concerning the breeding of companion animals. The issue at hand is that the majority of breeders have not/do not implement any selection for health. This has allowed detrimental genes and unhealthy anatomical extremes to accumulate over time. Health quality control and health-conscious breeding must be part of any mating in companion animals. Prospective breeding animals should be screened and health tested to select against detrimental and breed-related inherited traits and disorders.
There are many excuses that breeders can give as to why they do not health screen their breeding stock. None of these excuses absolve them from producing unhealthy animals with preventable inherited disease. Health screening and the selection of healthy breeding stock is the only means of improving the genetic health of companion animals.
AKC parent clubs have established breed-specific pre-breeding health screening requirements (https://www.ofa.org/breedtests.html). A similar listing of tests is not available for cat breeds, however breed related diseases are found on the International Cat Care website: www.icatcare.org/advice/cat-breeds <http://www.icatcare.org/advice/cat-breeds>. Veterinarians should counsel prospective pet purchasing clients to seek out health-conscious breeders that can provide health screening test results on the parents of companion animals they are producing. Veterinarians should counsel breeders to follow pre-breeding health screening requirements.
Regarding the Resolution:
I disagree with the singling out of Springer rage syndrome and recommend deleting it as an example of breed-related disease. The AVMA states that "...the intention of this policy is not to condemn individual breeds..." Rage syndrome is a rare pathological aggression that can be seen in several breeds and mixed-breed dogs. It does not occur at a high frequency in Springer Spaniels and its mention unfairly stigmatizes the breed.
This is different from the mentioning of "twisty cats" as this is a detrimental genetic malformation that occurs in all members of the "breed" and should not be propagated.
While "only animals without deleterious inherited disorders are selected for breeding" is the goal, the means of getting there is not so straight-forward. For recessive disorders where a genetic test is available, affected animals can be bred to (homozygous) normal-testing animals and no clinically affected offspring will be produced. Carriers can be bred to normal testing animals and replaced for breeding with normal testing offspring. For complexly inherited traits, breeding mildly affected to normal-screened animals will produce healthier offspring and move breeds away from detrimental disorders.
For breeds with brachycephalic syndrome and others with disorders that have a minor health effect (hypothyroidism, etc.) a statement to only breed "normal" animals could be so restrictive as to effectively eliminate entire breeds. Some breeds have been bred to anatomical extremes or genetic disorders have increased in frequency over decades by not selecting for health. Breeds should be allowed to focus health-based selection on "grading up" by breeding towards a less extreme anatomical conformation, and against genetic disorders that will produce a healthier breed without welfare issues. There are many examples of breeds where concerted and uniformly utilized breeding programs have been in place, genetic disease has declined, and breed health has improved.
In addition, a dogmatic statement against breeding provides ammunition for animal rights extremists to use the AVMA resolution to propose new legislation and regulations against the breeding of companion animals. This is also why I do not recommend singling out individual breeds using behavior as an example – there is already too much ill-advised breed-specific legislation versus proper aggressive dog legislation in the pipeline. The goal is to improve the genetic health of all breeds through health-conscious breeding.
In the "Statement about the Resolution" it states, "This may necessitate outbreeding until appropriate individuals can be identified within a breed." I recommend deleting this sentence. It is fallacious, and supposes that inherited disease comes from inbreeding instead of a lack of selection for health. All breeds by definition are inbred, and published data do not support that variations in inbreeding coefficients alone alter the expression of genetic disease. Breed-related genetic disease is already dispersed within breeds, so outbreeding will not reduce the frequency of affected individuals. This is not meant to advocate close inbreeding, but focusing on outbreeding will only delay breed improvement by distracting breeders to focus on a tool - the inbreeding coefficient - as opposed to directed selection against deleterious genes and disorders and for superior breeding individuals.
Dachshunds do not have extra vertebra predisposing them to disc disease - which involves biomechanical and other undetermined factors. This statement should also be deleted. The published literature shows that selection of Dachshund breeding dogs without radiographic evidence of disc calcification on a lateral radiograph diminishes the overall frequency of disc disease. Again, it is using scientifically validated health screening and selective pressure that reduces genetic disease.
I liken pre-breeding health screening to equine pre-purchase examinations. For an informed consumer it is a requirement; not an optional endeavor. This is a paradigm shift from the past (I’ve got a pet, you’ve got a pet – let’s breed them together). If a breeder is not willing to perform health quality control through pre-breeding health screening, they are doing a bad job. They need to find a hobby or occupation that they can actually be good at. Each breed and breeder needs to be educated on their responsibilities, as well as the discerning role of the pet purchasing consumer (our clients). This is not an easy road, but one the veterinarian must embrace as we are the professionals entrusted with the health of animals.
The attached article “Maintaining and Improving Breeds” was published in the AKC Delegates Perspectives newsletter this past September and outlines my views on breeding and maintaining healthy dog breeds. The same principles apply to other companion animal breeds.
Please let me know if you or the Delegate body would like further input on this matter. You can call me at my office 860-749-8348 or email Jerold.bell@tufts.edu <mailto:Jerold.bell@tufts.edu>.
Note: The recommendations from Dr. Bell and endorsed by the English Springer Spaniel Foundation were adopted.
