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Genetic Diseases in Golden Retrievers--
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Here at Gaylan's, we take the reduction of genetic disease in goldens as an important part of our role as breeders. To do this, we:
Screening is a critical part of our investigation into our breedings, both before and after. However, we also keep in mind that there are no perfect dogs in the world. This point is so important, let me say it again...THERE ARE NO PERFECT DOGS! Breeding is a process of making tradeoffs and weighing risks. Therefore, we are avid students of genetics and seek to make our breeding decisions based on sound science not simply genetic clearances. We seek to manage risks since alleviating them is not possible. Therefore, there may be times that we won't breed to a dog with all of his clearances because we believe the risk of genetic disease is too great and there may be times when we do breed to a dog who lacks a clearance because we believe what he has to offer outweighs this gap. You can be sure that we will discuss all of this thoroughly with you (probably more thoroughly than you would prefer :-)) and we will stand behind our decisions with our warranty. If you get one of our puppies, we will also ask you to support us in our program by submitting your pup to numerous genetic screening tests and providing us with the results. We do a tremendous amount of work to reduce the risk of genetic defects but we don't want to mislead you--it is NOT possible to successfully avoid all genetic problems in a breeding program. To expect this of a breeder is foolhardy. Even with all of our efforts over the last 29 years, we have experienced nearly every genetic problem on this list. (And we know that those we have no personal experience with are likely to show up in the future.) Breeding dogs, like any adventure in genetics, is a risky activity. At the present state of DNA testing, we cannot know the genetic makeup of our dogs thoroughly enough to avoid disease. But, we can study, test and discuss with the goal of limiting problems. We cannot promise you a perfectly healthy puppy but we can promise that we have used our experience and expertise to make sound judgements about genetic disease, that we have discussed the risks with you ahead of time, and that we will stand behind our puppies for their lifetime. This first portion of this list identifies the diseases that we feel are of most concern to golden retriever breeders and owners, in order of our priority. Unfortunately, not all of these diseases have screening tests available but, where they are, we use them to guide our breeding decisions. We seek to select away from these diseases, if it is possible to know it ahead of time. We also seek, if possible, to breed dogs with a majority of relatives--siblings, parents, and ancestors--who are not affected. We will also honestly evaluate the potential for genetic problems in our breedings and provide that information to you. In 2007, two eye diseases have roared onto the golden scene and are now a priority for us in our breeding program. They are progressive rod-cone degeneration Progressive Retinal Atrophy, known as prcd-PRA, and pigmentary uveitis. We are still developing our breeding strategy for these disease but we have added them into Part I below. The second portion of the list includes additional genetic diseases that affect goldens and for which we screen. These diseases either have inconclusive screening methods, do not debilitate affected dogs or are easily treated.
Part I Cancer. Recent surveys show that cancer is the #1 cause of death in golden retrievers. Their cancer rates equal some of the breeds long thought to lead the way in incidents of cancer, such as Boxers. This may be the greatest tragedy of the golden retriever in the 1990s. Cancers such as hemangiosarcoma (cancer of the blood) and lymphosarcoma (cancer of the lymphatic system) lead the list of killers of goldens. The breed's average lifespan is now down to 10 1/2 years. We strongly believe that goldens should be long-lived (12-16 years) and healthy and active during most of this time. However, there is no screening test for cancer so it is difficult to know if the dogs you are breeding to will live long and healthy lives. Our approach is to select bitches from lines where more than 75% of the dogs in the pedigree lived to at least 11 (longer than the golden average), to research the cause of death on as many dogs in the pedigree *and their siblings* as possible, and as often as possible to breed to older males who have already reached the average age. This means that it is unlikely that we will breed to today's top-winning dogs but we might be breeding to their sires if their pedigrees meet our other criteria. We are also committed to raising our dogs with as few chemicals as possible while still maintaining their health. We feed Bravo Raw Diet, a raw, natural diet based on human-grade materials at a minimum, certified organic if possible. We supplement our dogs with ProBalance, salmon oil, Animal Essentials and Dynamite products. We also no longer vaccinate our dogs regularly, choosing instead to check their immune status with blood titers using Cornell University's VAX-test program. Our vaccination program includes keeping puppies longer (8-9 weeks) so their first vaccine is given to a relatively mature immune system. We encourage our buyers to follow this program, as well. We have also added cancer to our warranty, offering a 6-year warranty against all fatal cancers.
There are presently two methods of screening dogs for CHD, both of which require hip x-rays. The most common screening is done through the Orthopedic Foundation for Animals (OFA) which issues clearances rating dogs EXCELLENT, GOOD, and FAIR. It also grades degrees of dysplasia as MILD, MODERATE, and SEVERE. Dogs with equivocal finds are considered BORDERLINE. At Gaylan's, we breed only cleared dogs with ratings of excellent, good or fair. OFA ratings are indicated by a number that looks like GR11111G24F. This indicates the x-rayed dog is a golden retriever (GR) with a clearance number of 11111 and a rating of "Good" (G) who was x-rayed at 24 months (24) and is a female (F). An excellent rating would be indicated by an E and a fair appears as an F after the rating number. More recently, the University of Pennsylvania has introduced a procedure that provides information about a dog's hips but does not offer clearances. Instead, PennHip grades the dog's likelihood of developing CHD using a distraction index (DI). We seek to breed dogs with a DI that puts them in the top 50 percentile for all golden retrievers. Presently, the average golden DI is .55 so dogs with DIs of .54 and below are in this percentile. Forty years of golden retriever history has also shown that breeding clear dogs is not enough to reduce the rate of hip dysplasia. Breeders must also seek to breed only dogs with pedigrees with both depth and breadth of clearances, and those who produce lower than average numbers of dysplastic puppies. Depth means that even dogs two, three, or four generations behind the sire and dam were shown to be free of dysplasia. Breadth of clearances means that many or most of the sire's and dam's siblings also had normal hip joint conformation. Gaylan's bitches have both depth and breadth of dysplasia-free pedigrees. We also monitor their production rates to ensure we are producing high percentages of cleared dogs and seek only to breed to dogs with similarly disease-free pedigrees and production rates. Our breeding methods have been effective in accomplishing two goals: reducing our overall rate of dysplasia in our dogs AND, as importantly, reducing the symptoms experienced by those dogs we breed that are dysplastic. As of early 2008, slightly over 91% of the dogs that we are producing have normal hip conformation. Of the 9% of dysplastic dogs that we produce, most have no symptoms throughout their lifetime; the disease was discovered at their two-year screenings and was never evident again.
The genetic disorder, prcd-PRA, causes cells in the retina at the back of the eye to degenerate and die, even though the cells seem to develop normally early in life. The “rod” cells operate in low light levels and are the first to lose normal function. Night blindness results. Then the “cone” cells gradually lose their normal function in full light situations. Most affected dogs will eventually be blind. Typically, the clinical disease is recognized first in early adolescence or early adulthood. Since age at onset of disease varies among breeds, you should read specific information for your dog. Diagnosis of retinal disease can be difficult. Conditions that seem to be prcd-PRA might instead be another disease and might not be inherited. OptiGen’s genetic test assists in making the diagnosis. It’s important to remember that not all retinal disease is PRA and not all PRA is the prcd form of PRA. Annual eye exams by a veterinary ophthalmologist will build a history of eye health that will help to diagnose disease.There are also other forms of PRA that affect goldens but these forms are still very rare and have not shown up in the lines that we breed to. Pigmentary Uveitis. Recently, pigmentary uveitis (PU) has been found to affect golden retrievers, including some of ours. This progressive inflammation of the eye is not due to infection or systemic disease, but appears to be a hereditary, immune-mediated disorder. This disorder affects older dogs (the average age of onset is 8 years old) of both sexes and is usually a bilateral condition. We will seek to avoid doubling up on PU in pedigrees to reduce the risk of affected dogs. We are participating in the Michigan State University research on PU in hopes of them developing a DNA test for this disease over the next few years. Once this test is developed, we will test all of our breeding stock. Part II.This portion lists additional genetic diseases that affect goldens and for which we screen, if possible. However, these diseases are a lower priority for us since they do not debilitate affected dogs or are easily treatable. Eye Problems. The most common eye problems of golden retrievers are bilateral, juvenile-onset cataracts and abnormalities of the eyelids/eyelashes. Contrary to its name, juvenile cataracts may not appear until the dog is five or six years old. Thankfully, most golden retriever cataracts are quite small and have little or no effect on the dog. We have produced a few dogs with juvenile cataracts but none whose sight was affected. We have not yet used an affected dog for breeding but do not rule it out given the minor form this disease takes in goldens. Optigen is very close to having a DNA test for this form of cataracts and we look forward to using it to identify our breeding stocks' genetic status when it becomes available. In addition, goldens may suffer from retinal dysplasia (RD), thought to be simple recessive. Mild forms of RD are only visible very early in the dog's life, disappearing by 3 or 4 months of age. Thus, we screen all of our litters at 8 weeks. We will breed puppies with retinal folds that resolve by 2 years of age but we will not breed dogs diagnosed with retinal dysplasia any time in their lives. Eyelid abnormalities in goldens include an inward rolling of the eyelid (entropion, ectropion) and the existence of extra eyelashes on the inside of the eyelid (distichiasis, trichiasis). We also do not breed dogs with entropion, ectropion or other serious eyelid disorder. However, we note but do not base breeding decisions on distichia.
The Canine Eye Research Foundation (CERF) provides certifying numbers to dogs cleared annually. CERF numbers are similar to OFA numbers except, since they must be repeated every year, they indicate the year and age of the cleared dog. Thus, CERF GR1111/96-24 is a golden retriever (GR) with clearance number 1111 who was seen by an opthamologist in 1996 when he was 24 months old.
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