Cardigan Welsh Corgi Diseases and Problems
All purebred dogs are prone to specific types of genetic diseases, but contrary to popular belief, most breeds of dogs are not more prone to disease in general than are mixed breeds. Mixed breed dogs are also prone to genetic diseases at a similar rate to purebreds, but their diseases are not tracked from generation to generation to know which ones are most likely to occur in the lines. Responsible breeders know their breed's common genetic diseases and do everything they can to breed away from them. For any diseases with tests available, breeders should test. For those without tests, breeders should look back through the pedigrees to see genetic health histories of their dog's ancestors and try to avoid breeding together lines with the same problems.
Hip and Elbow Problems
Hip dysplasia is a condition where the ball and socket portions of the hips do not fit or develop properly. Rather than sliding together properly, they rub and grind across each other, causing pain and loss of function. Large and giant breeds of dogs are especially affected by hip dysplasia, while smaller breeds can often technically have hip dysplasia with no symptoms. Small breeds should still be tested. Ethical breeders test hip condition via OFA or PennHIP and will give hip scores of the parents to potential puppy buyers. While some breeders choose to only breed dogs with hips of Good or better score, Fair is a passing score and is acceptable to breed to. In the interest of preserving genetic diversity, especially in very rare or already heavily inbred breeds, some breeders may choose to breed dogs with mild hip dysplasia to dogs with excellent hips. As long as the breeders are honest about this, it is not necessarily a red flag. [MORE INFORMATION]
Elbow dysplasia is similar to hip dysplasia but instead affects the elbows. There is no normal grade for elbows. Elbows with any grade mean they have dysplasia of some level. Testing for elbow dysplasia is an optional test in Caridgan Welsh corigs, as it has not historically been a major problem in the breed. [MORE INFORMATION]
Progressive Retinal Atrophy (PRA)
PRA is a genetic disease in which the retina of the eye degenerates and eventually leads to blindness. There are multiple genetic causes of PRA in dogs, but Cardigan Welsh corgis are prone to one called "Progressive Retinal Atrophy, Rod-Cone Dysplasia 3" (PRA-rcd3). There is a genetic test for this type of PRA, so parents of pups you are interested in should be tested for it. Two carriers (dogs with one copy of the mutated PRA-rcd3 version of the gene and one normal copy) should not be bred together, as there is a risk of puppies inheriting one copy of the mutated version from each parent and being affected by PRA. [MORE INFORMATION]
Degenerative Myelopathy (DM)
While this disease typically does not affect dogs until they are 8-14 years of age, it can be quite devastating when it does hit. It causes gradual paralysis in dogs and eventually death (if the dog does not die of other causes first) when the lungs become paralyzed, making it so the dog can no longer breathe. There is no "sure fire" test for DM, but there is a test which can identify dogs that are "at risk" of developing the disease so they can be not used in a breeding program. "At risk" dogs may or many not develop DM. "DM carrier" means the dog has the genetics to produce "at risk" puppies if it is bred to an "At risk" or "DM carrier" dog, but "DM carriers" will not develop DM themselves. They can be used in breeding so long as they are bred to a "DM clear" dog. If a dog is "DM clear by pedigree", it means neither parent was a DM carrier, so the offspring will also not have DM. Take this with a grain of salt, as sometimes mistakes in record keeping are made. I personally prefer to test all of my dogs, even if they are clear by pedigree. [MORE INFORMATION]
Intervertebral Disc Disease (IVDD)
IVDD is a disease in which the cushion in the spaces between the spine swell or rupture. There is a lot of misinformation surrounding IVDD. Some common myths is that all dwarf dogs will get IVDD or that all dwarf dogs have the same risk of IVDD. Another is that a dog gets an Embark DNA test stating the dog is "at risk" because it has one to two copies of the CDDY allele (one of the gene mutations responsible for dwarfism in dogs) will get IVDD. The Embark DNA test only tests for CDDY, which is prevalent in most dwarf dog breeds. Having at least one copy of CDDY is necessary for a dog to get this type of IVDD, but most dogs with CDDY never get IVDD. While we don't currently know what all of the factors involved in risk of IVDD are, the Cardigan Welsh Corgi Club of America and the Dachshund Club of America, Inc. are working together to research them.
Some of the known research in Dachshunds is as follows:
Dachshunds have a higher frequency of IVDD than Cardigans, and some breeds (such as cocker breeds) almost all have CDDY but almost never have IVDD, suggesting one or more of the following:
As we don't currently have good Cardigan-specific data on IVDD, Cardigan breeders and owners are working off what is known about Dachshunds [MORE INFORMATION]. One final note, however, is that, early neutering is correlated with higher risk of IVDD in corgi breeds. While the study unfortunately combined both Pembrokes and Cardigans and had fairly low numbers of each, the correlation makes it worth using caution. I personally recommend waiting to neuter males until they are 2 years old or opting for a vasectomy rather than a traditional neuter. You can read more about the science behind best spay/neuter practices [HERE].
Some of the known research in Dachshunds is as follows:
- Moderate exercise lowers risk of IVDD symptoms.
- Frequent climbing of stairs increases risk of IVDD symptoms, but moderate climbing lowers risk.
- Dogs that develop IVDD symptoms are more likely to produce pups that later develop IVDD symptoms.
Dachshunds have a higher frequency of IVDD than Cardigans, and some breeds (such as cocker breeds) almost all have CDDY but almost never have IVDD, suggesting one or more of the following:
- Dachshunds have a higher frequency of CDDY mutation rather than the over common dwarfing mutation, CDPA. Less likely, as we know multiple breeds with high frequency of CDDY that have very low frequency of IVDD. [MORE INFORMATION]
- Other, as-of-yet-unknown genes (which may be more common in Dachshunds) are involved in true risk of IVDD. This is more likely.
- Environmental factors also likely interact with both CDDY mutation and the as-of-yet-unknown genes.
As we don't currently have good Cardigan-specific data on IVDD, Cardigan breeders and owners are working off what is known about Dachshunds [MORE INFORMATION]. One final note, however, is that, early neutering is correlated with higher risk of IVDD in corgi breeds. While the study unfortunately combined both Pembrokes and Cardigans and had fairly low numbers of each, the correlation makes it worth using caution. I personally recommend waiting to neuter males until they are 2 years old or opting for a vasectomy rather than a traditional neuter. You can read more about the science behind best spay/neuter practices [HERE].
Cancers
Cancers of various types are common in many breeds of dogs and in mixed breeds of dogs. Cancer was the leading cause of death (~28% of dogs in the survey) in Cardigans, according to a [REPORT] from the Kennel Club/ British Small Animal Veterinary Association Scientific Committee.
While most cancers have at least some genetic component, environment also plays a large part. Diet and exposure (or lack thereof) to cancer-causing agents (called 'carcinogens') affect a dog's likelihood of getting and succumbing to cancer. There is [EVIDENCE] that feeding vegetables such as carrots and leafy greens (not broccoli, cabbage, or brussels sprouts, but rather vegetables like leafy green lettuces) can reduce the risk of a specific kind of cancer in Scottish terriers. While we don't know for sure that it also helps reduce the risk of cancers in other breeds, many veggies are a healthy addition to a dog's diet, anyway. For this reason, some canine nutritionists advise adding [DOG SAFE FRUITS AND VEGETABLES] to your dog's diet. There is little to no risk in adding these foods, and many offer other nutritional benefits and/or can be used as low calorie treats. If you do plan on feeding vegetables such as broccoli, cabbage, or brussels sprouts, be sure your dog does not have thyroid problems or fully cook the veggies first, as they contain an enzyme when raw which can affect thyroids. Fresh carrots, strawberries, apples, and green beans are foods many dogs enjoy.
Hemangiosarcoma
While breeds such as golden retrievers and boxers are at the highest risk of hemangiosarcoma (cancer of the cells which line the blood vessels), it is also known to occur in Cardigans. Because of the location of the cells, the cancer can easily spread and develop tumors in other organs such as the spleen, heart, and liver. Affected dogs typically show signs between 8-13 years of age, but incident rates in Cardigans and breed studies are lacking. [MORE INFORMATION]
Lymphoma
Lymphoma is a common type of cancer in all breeds of dogs. The mode of inheritance in Cardigans is as-of-yet unknown, though specific markers have been found for other breeds. Age of onset can be early or late in life. Lymphoma is [CORRELATED] with desexing (spaying) female dogs, with a significantly lower risk of intact females developing lymphoma. This is one argument for ovary-sparing spays (OSS), which preserves the estrogen production.
Mammary Cancer
Whereas lymphoma risk is reduced by not removing the sex hormones (estrogen), mammary cancer risk increases in unspayed dogs. The same genes involved in increased risk of breast cancer in humans are also involved in increased risk of breast cancer in English Springer spaniels (and likely in other breeds). A variant in English springers is linked with a lower risk of mammary cancer, indicating that the variant of the gene has some protective immune defense. All female dogs (spayed or not) should be regularly checked for mammary tumors, and suspicious lumps should be biopsied by a vet. The sooner a tumor is discovered, the better the chance of survival. [MORE INFORMATION]
While most cancers have at least some genetic component, environment also plays a large part. Diet and exposure (or lack thereof) to cancer-causing agents (called 'carcinogens') affect a dog's likelihood of getting and succumbing to cancer. There is [EVIDENCE] that feeding vegetables such as carrots and leafy greens (not broccoli, cabbage, or brussels sprouts, but rather vegetables like leafy green lettuces) can reduce the risk of a specific kind of cancer in Scottish terriers. While we don't know for sure that it also helps reduce the risk of cancers in other breeds, many veggies are a healthy addition to a dog's diet, anyway. For this reason, some canine nutritionists advise adding [DOG SAFE FRUITS AND VEGETABLES] to your dog's diet. There is little to no risk in adding these foods, and many offer other nutritional benefits and/or can be used as low calorie treats. If you do plan on feeding vegetables such as broccoli, cabbage, or brussels sprouts, be sure your dog does not have thyroid problems or fully cook the veggies first, as they contain an enzyme when raw which can affect thyroids. Fresh carrots, strawberries, apples, and green beans are foods many dogs enjoy.
Hemangiosarcoma
While breeds such as golden retrievers and boxers are at the highest risk of hemangiosarcoma (cancer of the cells which line the blood vessels), it is also known to occur in Cardigans. Because of the location of the cells, the cancer can easily spread and develop tumors in other organs such as the spleen, heart, and liver. Affected dogs typically show signs between 8-13 years of age, but incident rates in Cardigans and breed studies are lacking. [MORE INFORMATION]
Lymphoma
Lymphoma is a common type of cancer in all breeds of dogs. The mode of inheritance in Cardigans is as-of-yet unknown, though specific markers have been found for other breeds. Age of onset can be early or late in life. Lymphoma is [CORRELATED] with desexing (spaying) female dogs, with a significantly lower risk of intact females developing lymphoma. This is one argument for ovary-sparing spays (OSS), which preserves the estrogen production.
Mammary Cancer
Whereas lymphoma risk is reduced by not removing the sex hormones (estrogen), mammary cancer risk increases in unspayed dogs. The same genes involved in increased risk of breast cancer in humans are also involved in increased risk of breast cancer in English Springer spaniels (and likely in other breeds). A variant in English springers is linked with a lower risk of mammary cancer, indicating that the variant of the gene has some protective immune defense. All female dogs (spayed or not) should be regularly checked for mammary tumors, and suspicious lumps should be biopsied by a vet. The sooner a tumor is discovered, the better the chance of survival. [MORE INFORMATION]
Other Problems
The following are not necessarily genetic diseases, but they should be taken into consideration when breeding Cardigan Welsh Corgis because they can have an affect on health.
Merle
Since merle only affects black-brown pigment (rather than red-yellow pigment), red/yellow dogs do not show merle even if the dog is hiding the gene version for it. Merles can come in blue merle (black base), red merle (liver/chocolate base), dilute merle (black or liver + dilution). They can be with or without tan points or brindle points. Red and dilute merle are very uncommon in Cardigans because liver and dilute colors are both unacceptable according to the standard, so reputable breeders do not intentionally breed for them. They can pop up sometimes even in well-bred litters if both parents carry the genetics for them. Merle is also called 'dapple' or 'harlequin' in some breeds.
* Visible, classic merle. For more information on other merle length alleles [CLICK HERE]. |
Merle is a beautiful pattern in dogs, and it is a naturally-occurring color in Cardigan Welsh Corgis. However, two merle* dogs should not be bred together because there is a 25% chance of each individual puppy being "double merle". Double merles are mostly white, and they are often deaf, have vision problems, and have health issues. Micropthalmia is a common eye problem in double merles, as shown in the double merle Great Dane picture below. This is a condition in where one or both eyes are abnormally small and have malformations.
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Whitehead
Whitehead is an unknown allele or alleles* currently being [RESEARCHED]. As the name suggests, it causes white on the head. When the white spreads across much of the head, it increases the risk of deafness in one or both ears. Whitehead is not the same as piebald nor Irish white. Piebald is currently the only one of the three with a genetic test available.
(*Alleles are variants of genes) The video to the right compares the spread of white in piebald versus whitehead. Spread of white does not mean that an individual dog will progressively get more white. Rather, it means that through the generations, as more white appears (usually from breeding similar levels of white to each other), it typically follows these patterns. A piebald that is heavily white on the head is also likely to be nearly or completely white on the body. A whitehead that is heavily white on the head may still have quite a bit of color on the body. Notice that both piebald and whitehead can mimic Irish white pattern. It will be interesting to follow the research and see whether Irish white interacts with whitehead. Piebald, Irish white, and whitehead are all known to exist in Cardigan Welsh corgis, though piebald is not as common. |
So far it seems that breeding a dog with any whitehead characteristics to another with any whitehead characteristics risks a more extreme whitehead pattern. This would suggest incomplete dominance mode of inheritance (plus likely interaction with other alleles). Below are examples of a "double whitehead" or "extreme whitehead" where the entire head is white.
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Single whitehead traits are as follows:
- Split face (one half of the face predominantly white, sometimes with a blue eye on the same side of the face)
- All white muzzle
- White face that connects to a white neck
- Irregular/asymmetrical wide blaze
- Sometimes also a wide blaze (wider than the width of an eye)