{ My Life As Meowmy } : Improving The Breed - Health Tests
- Kyla Herbst
- Sep 5, 2016
- 5 min read
Let's talk genetic health. Did you know that the choices breeders make not only affect the structure and personality of the animals they breed, but also their likelihood of living a long, healthy life? That's right, deciding to become a breeder means undertaking the heavy responsibility of becoming morally accountable for the genetic health of the animals they breed. This accountability comes in many forms, but one of them we'll talk about today, is the importance of genetic testing. This article is a bit technical, but bear with me. Understanding this key element of responsible breeding practices can help you as a pet owner to make a wise choice when you are looking for a breeder to acquire your next fur-baby from!
Thanks to many advances in modern science and medicine, we are the beneficiaries of years of research into many of the destructive diseases which can affect the feline physiology. Some of the more common of these diseases include HCM, PKD, and PRA. (I know, you're thinking "whaaaat?" Don't worry, I'll explain more.) These common diseases now have simple genetic tests that can be performed to determine their inheritability. Groups like the UC Davis Veterinary Genetics Laboratory have programs allowing breeders to send in an oral swab for testing on a wide variety of diseases, for a very affordable cost. (They can even test for coat colors, lengths, and textures!) By utilizing programs like these, breeders can make sound decisions about whether to keep a certain cat in their breeding program at all, and if they do, which mates would be appropriate for that cat. Since the goal of breeding should be to improve the breed, these tests are extremely important in determining which cats should be bred and which should be placed as pets, in order to preserve the health and standard of the breed long-term.
Common Genetic Diseases of Cats
HCM: Hypertrophic Cardiomyopathy. This is the most common heart disease found in cats (it's also found in humans.) Ultimately this disease is fatal, though symptoms are not always apparent. It causes a thickening of the walls of the heart, which can lead to blood clots, a disruption of heart rhythm, or eventual heart failure. Sudden death may be the only symptom. There is no cure. Most commonly found in the Maine Coon, Ragdoll, American Shorthair, and British Shorthair. The disease can be passed on genetically by one parent, even if the other does not carry the gene. Testing is available and recommended.
PKD: Polycystic Kidney Disease. This disease causes the progressive development of cysts in the kidneys. These reduce the kidney tissue and impair their ability to function. Symptoms are general lack of wellness, loss of weight, lack of appetite, lethargy, and increased drinking of water. There is no cure for this disease. The disease can be passed on genetically by one parent, even if the other does not carry the gene. Commonly found in Persians and breeds related to the Persian, including British Shorthair. Testing is available and recommended.
PRA: Progressive Retinal Atrophy. This disease causes the degeneration of the retina of the eye, eventually leading to blindness. The disease is not fatal, however there is no cure. Commonly found in Abyssinian, Somali, Ocicat, and other Siamese-related breeds. There are several types of PRA known, and several tests available as well. PRA can have dominant inheritance, recessive inheritance, or no known inheritance at all, depending on what kind it is. Testing is available and recommended.
So how does this testing thing work? Let's use the testing for HCM within my own cattery as an example: Before I ever breed a cat, the first thing I do when they are near breeding age is send in an oral swab to UC Davis for a full panel of tests including AB Blood Type, HCM, and PKD. Since PRA is not commonly found in Ragdolls (or at all) this is not one of the tests I have done. Sometimes I'll also have the test for color done, to determine what color kittens I can expect to come out of the cat. (This is not necessary and can be determined just as easily by breeding the animal and seeing what they have!) When the tests come back, I examine them to see if there are any bad surprises. For HCM, for example, what I'm expecting is a N/N result. This would mean that there are no mutations of the HCMrd gene present. I can go ahead and breed this cat with no fear of passing on a genetic inheritance of HCM. If the result comes back N/HCMr, this would mean that the cat would have one copy of the Ragdoll HCM gene mutation present in their DNA. This means that although they may not be at high risk of passing on the gene, the possibility is there. Personally, I would NOT take the risk of breeding this cat, even to a N/N mate. They would be spayed or neutered and placed in a pet home, with full disclosure of this information. The same would be the case if the results came back HCMrd/HCMrd, as this cat would obviously be at an extremely high risk of developing and passing on HCM, and obviously would not be a good candidate for breeding. While it's true that there is a significant monetary loss if a cat purchased with the intent of breeding turns out to have a positive result on any genetic test, the peace of mind of knowing you're choosing not to knowingly contribute unhealthy genetics to the gene pool, outweighs the monetary loss. Unfortunately this is a risk you run as a breeder, which is why it's always wise to do your research on the bloodlines you're interest in /before/ purchasing cats for breeding, and/or make sure that the breeder you're buying from can provide you with N/N test results from both parents before purchase. (This goes for all genetically inheritable DNA mutations, not just HCM.)
*****One caveat to this information is this: In the instance of a breed which has a limited gene pool (not many of the breed exist or are available to breed to), there MAY be an occasion where the breeders working for the preservation of this breed may have to make a tough decision on which cats they will or will not breed. Some cats who are N/HCM may have to be bred to N/N cats in order to preserve the gene pool as a whole, with the goal being that the N/N offspring of this match can later be added to a breeding program. Thankfully, Ragdolls are not in this special category, so we don't have to make those tough calls. There are so many healthy, N/N Ragdolls available for breeding, that there would rarely be a logical reason to breed a N/HCMrd at all. Note that this would not apply to a cat that is HCM/HCM (carrying two copies of the gene mutation) as there would be no advantage to breeding such a cat.*****
What Other Breeders Have To Say
"British Shorthair cats require genetic testing for PKD to help insure that the disease is not passed on to future offspring. We also like to test for the long hair gene and for color. This lets us determine suitable pairs for breeding to achieve the desired outcome." ~Renae Silver, SilverCharm British Shorthairs
Bottom Line: Making wise use of genetic tests contributes to the overall health of any breeding program. Pet parents should be able to have peace of mind knowing that the breeder they’ve chosen has done all they could to ensure that their new furry family member will enjoy a long, healthy life – free from genetically inherited disease.
What do you think:
Is genetic testing something you'll keep in mind when looking for a breeder?
Questions? Comment below!
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