Tufts' Canine and Feline Breeding and Genetics Conference, 2009

Responsibility; noun. Duty, obligation, burden

What is the responsibility when someone decides to breed two cats or two dogs together to produce a litter? Everyone knows that genetic disease can occur in any animal. A dog or cat with genetic disease suffers morbidity and/or mortality. For most genetic diseases, we know how to either prevent their occurrence, or at least lessen the possibility of producing offspring with genetic disease. This can occur through the genotypic testing of the parents (identification of parents carrying liability genes for genetic disease), phenotypic testing of the parents (identification of parents affected with genetic disease), or pedigree analysis (identification of carrier risk based on the knowledge of carrier or affected relatives).

Simple Mendelian (one gene pair) disorders with a direct genetic test are absolutely preventable. All that it takes is testing the parents prior to making breeding decisions. Most genetic disorders cannot be absolutely prevented. They have complex, multi-gene inheritance, and liability genes have not been identified. However, for most of these inherited disorders, a method of diagnosing affected individuals is documented. It is also documented which breeds have a higher liability for these inherited disorders. Breeding decisions based on test results or diagnoses by health conscious breeders is a powerful tool for improved genetic health.

When informing a breeder of a diagnosis of genetic disease in a dog or cat that they have bred, you may hear several responses. A positive response would include concern, but also gratitude for the information. You cannot modify breeding practices and improve health without knowledge of the good and bad traits being produced. More negative responses include: I didn't know that was a problem in my breed. I have never produced that before. I'm not really a breeder - I just bred my own dog (or cat). I don't make money selling my kittens (or puppies). Genetic tests are so expensive. I was assured that the stud was tested negative for that disease. I didn't even know there was a test for that. That's not a genetic disease: We call them runts - it just happens. I didn't know about any of this.

Excuse; noun. An explanation offered for a release from an obligation or responsibility

Occasionally a genetic disease just appears without warning. However, most common genetic diseases are predictable. Using valid breeding strategies, these genetic diseases are for the most part preventable. It is time for us as veterinarians, breeders, AND the general public to step up to our ethical obligation and responsibility regarding the prevention of genetic disease.

Responsibilities of Veterinarians

When someone calls the veterinary hospital to make an initial appointment for a kitten or puppy, the owner should be told to bring 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 are identified by looking up the breed. For dogs, these are listed on the Canine Health Information Center (CHIC) website: www.caninehealthinfo.org/breeds.html. A similar listing of tests is not currently available for cats, however breed related diseases are found on the Feline Advisory Bureau (FAB-UK) website: www.fabcats.org/breeders/inherited_disorders.

For many disorders, genetic test results for individual breeding animals are available on-line. The Orthopedic Foundation for Animals maintains registries for testable genetic disorders in dogs and cats on their searchable website: www.offa.org/search.html. (Figure 1) You can type in the parent's name or registration number (from any registry; AKC, CFA, TICA, UKC, Sally's Registry, etc.), and if test information is available the animal's webpage will come up. This is Facebook for cats and dogs, with their own web pages and health test information. (Figure 2) If a dog's information does not come up on the OFA website, you should also check the Canine Eye Registry Foundation (CERF) website for eye examination results: www.vmdb.org/verify.html.

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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. For testable cat diseases there is currently no web-based registry. Persian or Himalayan cats should have polycystic kidney disease (PKD) results, and Maine Coon Cats and Ragdolls should have hypertrophic cardiomyopathy (HCM) results. A list of available genotypic tests is included in the Tufts conference proceedings: www.vin.com/tufts/2009.

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If no verified test results are available, then the puppy or kitten 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 tells you that they are planning on breeding a dog or cat, you can look up the pre-breeding health test requirements on the CHIC or FAB websites and print these out for them. 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. These can be found on the OFA website: http://www.offa.org/clinics.html, or on an excellently maintained Cavalier King Charles Spaniel website: http://www.cavalierhealth.org/health_clinics.htm. 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 or a pedigreed cat, you should counsel them on the behavioral and genetic expectations for the selected breeds. Provide them with a list of the genetic health test requirements from the CHIC or FAB websites. Ensure they understand that they should only purchase a pet from parents that have verified results of their breed-specific required health tests. See Responsibilities of the General Public (below) for more information.

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 or cats. These include matings between two members of the same breed, or crosses between two members of different breeds (designer matings). The fallacy that mixed-breed dogs and random-bred cats have less genetic disease is disproven every day in veterinary hospitals. The most common genetic diseases of; canine hip dysplasia, valvular heart disease, patella luxation, hypothyroidism, feline diabetes, and lower urinary tract disease/inflammatory cystitis 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 you are not willing or able to have the prescribed pre-breeding genetic tests performed, then you should find a different hobby or profession. Dogs and cats are living beings. It is not ethical to forgo the obligation of genetic testing.

Breed specific pre-breeding health test requirements are available on the CHIC or FAB websites (see links above). It is not necessary that your breeding stock pass all of the required health tests. Dogs become CHIC certified by completing the health requirements, regardless of the test results. This shows health consciousness. With direct genetic tests for recessive disorders, carriers can be bred to normal testing mates. This prevents affected offspring from being produced. The long-term goal is to have normal testing breeding stock. With quality carrier breeding stock, you can prevent affected offspring, and replace quality carriers with normal testing offspring for your next generation of breeding stock.

Dogs or cats affected with an autosomal dominant disease should be selected against, as half of their offspring will be affected with the genetic disorder. With polygenic or complexly inherited disorders, knowledge of the test results or affected status of the close relatives allows the breeder to recognize the risk of producing the genetic disorder. Breadth of pedigree normalcy (test results of the siblings of prospective breeding animals) gives a better indication of the genetic load of normal genes that the prospective breeding animal may carry. Breadth and depth of pedigree normalcy can be visualized in vertical pedigrees on the animal's page of the OFA website (Figure 3). For more complete breeding recommendations, see Breeding Strategies for the Management of Genetic Disorders on the Tufts conference website: www.vin.com/tufts/2009.

As stated previously, complexly inherited disease and diseases without direct tests for carriers cannot absolutely be prevented. No one wants to produce genetic disease, and we can all empathize when it does occur. If you are doing genetic testing and plan matings accordingly, you are doing your best to be health conscious and fulfilling your breeder responsibility.

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 your animal. Conscientious breeders understand that negative test results limit their breeding options. With direct gene tests, you can use carriers when bred to normal testing mates. For disorders without direct gene tests, you may have to choose a normal relative, as opposed to one you were planning on using in the next generation. We all recognize the excuse of, "Don't throw the baby out with the bath water." Matings should be planned that prevent or minimize the risk of producing genetic disease.

When your prospective breeding stock has a carrier or affected test result, please release this information to the OFA or other listing registry. (You have to mail CERF results in to release negative eye examination results.) 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. An OFA webpage of all normal individuals is great to see, but of little value if those with negative results are not listed. 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, you can search the OFA, CERF, CHIC or other websites for genetic test results on prospective mates. The OFA search page is extremely flexible and useful on search requirements (Figure 1 above). If test results are not available on dogs and cats 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 or kitten, please provide your 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 or kittens, these results should be provided. It is not enough to say that the testing was done. If testing was done then you have 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 kitten or puppy. Health guarantees that provide for replacement of puppies or kittens 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. This is not a toaster.

You should follow up on offspring that you have produced. Have birthday parties, or call owners on the pet's birthday to see how they are doing. Owners will value your interest in their pet's well being. If an owner's pet is discovered to have a problem, show your concern. Owners understand that a breeder cannot predict or prevent every health problem, and will appreciate your health consciousness.

Responsibilities of the General Public

When you as a consumer get a puppy or a kitten, the emotional aspect of adding a new member of your family often overwhelms the rational aspect of this important decision. Acquiring a new pet should not be an impulse decision. Your new pet will hopefully be with you for the next 10 to 15 years. You should spend as much time researching this decision as you do when you purchase a new car or a refrigerator.

You need to research whether a specific breed is suitable for you and your home. You also need to research the breed specific health testing requirements for the selected breed from the CHIC or FAB websites (links above). Both parents of kittens or puppies that you are considering should have all of their breed specific test results completed and available on official on-line registries such as the OFA and CERF (links above), or you should be provided with copies of the official test results on the parents. Whether you are purchasing from a private breeder, one you found on the internet, or a pet store, the parental health testing results should be available. If they are not available, then just walk away - regardless of how cute the puppy or kitten.
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. All genetic disease is not preventable. A breeder that has performed the required pre-breeding health tests is doing what they can to provide a healthy pet.

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, walk away. They have 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 kittens and 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 and cats. It is your choice of where you get a puppy or kitten. It is the general public's obligation to document genetic health testing from breeders.

The frequency of genetic diseases can be significantly decreased, if not eliminated by valid testing and breeding selection in purposely bred dogs and cats. We are now at the point where the tools are available, and the information is well established. 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 health of dogs and cats. It is up to all of us to educate each other about producing genetically healthy cats and dogs, and call for documentation of health testing of all breeding stock.

This article may be reproduced with the permission of the author. Jerold.Bell{at}tufts.edu