Facing Breed Related Diseases as a Vet ; Practical & Ethical Aspects

2010 WSAVA Congress Proceedings


Facing Breed Related Diseases as a Vet–Practical and Ethical Aspects
Jerold S. Bell, DVM
North Grafton, MA, USA

Responsibilities of Veterinarians

With each hereditary issue, we as a veterinary profession are being called upon to determine what is “normal”, what is “abnormal”, and what screening tests can be performed to allow selection away from disease causing phenotypes. Care must be taken, so that selective pressures are not so severe that they limit genetic diversity in the breed gene pool.

When a client makes an initial puppy appointment, we should examine all of the paperwork provided by the breeder or pet store. This includes not only the prior medical care, but the registration paperwork that lists the sire and dam. On receiving the paperwork, the health test requirements for the breed can be identified, and the health test results of the parents searched. If test results are not available on the web-based registries, ask the owner if the breeder provided them with verification of each of the required genetic test results on the parents; i.e., a copy of the official test results from the testing agencies. If no verified test results are available, then the puppy was not bred by a health conscious breeder. There is no expectation of genetic health in your patient, and you and the owner can only hope for good health.

When a client is planning on breeding a dog, you can look up the pre-breeding health test requirements. You can provide many of the tests yourself (radiographs, thyroid profile, or cheek swab or blood samples for genetic tests). For eye examinations or heart examinations by a cardiologist, you can assist your client by providing information on local health screening clinics. You must emphasize the ethical responsibility of pre-breeding genetic testing, or a decision to not breed their animal. Genetic testing is a requirement, not a choice.

If a client is looking to purchase a purebred or designer-bred dog, you should counsel them on the behavioral and genetic expectations for the selected breeds. Provide them with the genetic health test requirements. Ensure they understand that they should only purchase a pet from parents that have verified results of their breed-specific required health tests.

Responsibilities of Breeders

It is the ethical responsibility and obligation of all breeders to perform the available required pre-breeding genetic health tests on prospective breeding stock. A breeder is anyone that plans a mating between two dogs. These include matings between two members of the same breed, or crosses between two members of different breeds (designer matings). The most common genetic diseases of canine hip dysplasia, valvular heart disease, patella luxation, and hypothyroidism occur at similar frequencies in mixed-breed versus pure-bred populations. If two animals are purposely bred, then the breed-specific genetic testing for each parent is required.

Most genetic tests only need to be done once in the prospective breeding animal’s lifetime. Others (eye examinations, phenotypic heart examinations, thyroid profile, etc.) should be repeated, depending on the breed specific age of onset of the disorder, and age requirement for diagnosis.

If a breeder is not willing or able to have the prescribed pre-breeding genetic tests performed, then they should find a different hobby or profession. Dogs are living beings. It is not ethical to forgo the obligation of genetic testing.

Everyone loves their breed, and their own breeding stock. The more genetic tests that are developed, the greater chance there is of identifying an undesirable gene in an animal. Conscientious breeders understand that negative test results limit their breeding options. With direct gene tests, they can use carriers when bred to normal testing mates. For disorders without direct gene tests, they may have to choose a normal relative, as opposed to one they were planning on using in the next generation. Matings should be planned that prevent or minimize the risk of producing genetic disease.

When prospective breeding stock has a carrier or affected test result, you should counsel your client to release this information to the listing health registry. If negative test results are not made available, then other breeders will not be able to ascertain the disease risk of their own breeding stock to make informed breeding decisions. As opposed to the stigma that used to be attached to the appearance of genetic disease, the stigma now rests on those that hide the occurrence of genetic disease. Dealing with genetic disorders is a community effort.

When making breeding decisions, breeders can search the health registry websites for genetic test results on prospective mates. If test results are not available on dogs that have already been bred, then it must be assumed that they are affected or carriers. Otherwise the results would be available.

When selling a puppy, breeders should provide new owners with full documentation of the health test results (copies of official test results) on the parents. If early direct genetic testing was done on the puppies, these results should be provided. It is not enough to say that the testing was done. If testing was done then the breeder has the paperwork, and it should be provided. It must be impressed upon the public that health consciousness is one of the most important considerations when getting a puppy. Health guarantees that provide for replacement of puppies with genetic defects are not a replacement for health testing. Such a guarantee is of little value, as no one wants to part with their family member once the emotional bonds have been made. A puppy is not a toaster.

Responsibilities of Breed Organizations/Parent Clubs

It is the responsibility of the breed club to conduct regular breed health surveys to monitor the health of the breed. If breed-related disease is present, it is up to the breed club to promote and fund research to identify phenotypic and genotypic tests that can be used by breeders to improve the genetic health of the breed.

For dog breeds, the parent club should work with CHIC, the Kennel Club, or other national agencies to select the required and recommended genetic testing that should be performed before dogs are bred. Breeders should be counseled to perform pre-breeding health testing.

Parent clubs should review their breed standards and select against morphological changes that promote disease, morbidity, or mortality. They should counsel their breeders against breeding to extreme standards that can promote disease, and should educate judges to select against morphology that promotes disease.

The parent club should also scientifically monitor if significant health issues are being caused by a lack of genetic diversity. If so, they should be open to scientific measures that can increase genetic diversity, including opening of the stud book, or even controlled crossbreeding programs.

Responsibilities of the General Public

When a consumer gets a puppy, the emotional aspect of adding a new member to the family often overwhelms the rational aspect of this important decision. Acquiring a new pet should not be an impulse decision. The new pet will hopefully be with the family for the next 10 to 15 years. The public should spend as much time researching this decision as they do when purchasing a new car or a refrigerator.

Prospective owners need to research whether a specific breed is suitable for them and their home. They also need to research the breed-specific health testing requirements for the selected breed. Whether purchasing from a private breeder, one found on the internet, or a pet store, the parental health testing results for both parents should be available. If they are not available, then just walk away–regardless of how cute the puppy.

Statements of testing by the breeder, or on a breeder website are not sufficient to document health test status. If the testing has been done, the breeder will be happy to provide the official documentation that they are a health conscious breeder. Health guarantees that provide replacement for pets with genetic disease do not eliminate the need for genetic testing. If a breeder states that they do not have the health test documentation, but offer a guarantee of genetic health, the prospective owner should walk away. The breeder has not fulfilled their ethical responsibility and obligation of health testing.

The general public is the engine that drives the pet breeding industry. If the general public demands puppies from health tested breeding stock, then the market will change to favor health conscious breeders. If people can easily sell pets to the public on a website without any health tests being done, then there is no market force to change the situation to improve the genetic health of dogs. It is the public’s choice of where they get a puppy. It is the general public’s obligation to document genetic health testing from breeders.

All genetic diseases are not preventable. However, the frequency of genetic diseases can be significantly decreased, if not eliminated by valid testing and breeding selection in purposely bred dogs. It is time to put an end to the excuse of ignorance of the breeder, veterinarian, or general public in their roles and responsibilities to improve the genetic health of dogs. It is up to all of us to educate each other about producing genetically healthy dogs, and call for the documentation of health testing of all breeding stock.

Inherited Diseases in Dogs : Cambridge University

This web site contains a guide to diseases/conditions of pure bred dogs which are likely to be transmitted wholly or partly through a genetic mechanism.

* Search the Inherited Diseases in Dogs Database

The site is not designed as a diagnostic system, and I cannot offer individual veterinary advice. If you suspect that your dog is suffering from one of these conditions, contact your veterinarian. The information in the site is correct to the best of my knowledge and belief, but it is necessarily incomplete, and I can give no warranty of accuracy, express or implied. I would be grateful for any corrections, and in particular for information on conditions or references omitted. Please email me with information.

The Inherited Diseases in Dogs Database is compiled by David Sargan. Publications referring to this site should cite Sargan, D.R. IDID: inherited diseases in dogs: web-based information for canine inherited disease genetics. Mamm Genome. 2004 Jun;15(6):503-6.