SANSUI SOU SHIKOKU KENNEL
HEALTH ISSUES IN THE SHIKOKU KEN
One of the reasons many people are drawn to Shikoku and the other native Japanese dog breeds is their reputation for being healthy and relatively long-lived. While this may be true when comparing them to some breeds, there are still some issues seen in the breed that prospective Shikoku owners should be aware of.
One of my goals as a Shikoku breeder is to educate dog owners so they can make well-informed decisions about the dogs they spend their lives with. It is not my intention to scare people away from the breed, but to make sure they are aware of the issues so if they experience health problems in their own dogs they aren't caught off guard and they know how to proceed. It can also be very helpful to share this list of possible issues with your veterinarian. With such a rare breed, most vets will likely have never heard of Shikoku let alone be familiar with the potential health issues they face.
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While all of the health issues outlined here can happen, when we look at the number of affected dogs for each condition and compare that to the population as a whole, I'd actually classify most of these as fairly rare or uncommon. The exception to those is hip dysplasia and cancer, though not to the level of concern those issues have for some breeds where hip issues and cancers are a major problem.
ORTHOPEDIC
While hip issues are likely to be the most common orthopedic issue in Shikoku, patellar luxation isn't unheard of and elbow dysplasia should be screened for as well.
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Looking at the population of tested Shikoku, hip scores currently leave a lot to be desired, meaning Shikoku breeders have a long road ahead of us to work to improve hips in the breed.
Health testing for orthopedic issues is done by taking x-rays (hips, elbows) or physical manipulation (knees) to check for abnormalities. There is currently no DNA testing available for these issues meaning that dogs with good scores can still be carriers and produce offspring with poor hips, knees, or elbows, and it can be difficult to know until a dog is born with these issues.
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If caught early, surgery can often be done to correct major orthopedic issues. Less invasive treatment plans like chiropractic, muscle conditioning, and hydrotherapy can also be very successful for orthopedic issues. Joint supplements are also an excellent way to support joint health.
SEIZURES/ EPILEPSY
The underlying cause of seizures in Shikoku is unknown, although it is believed that there is a genetic component as quite a few of the known affected dogs are closely related individuals.
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It is possible that there is a link between seizures and autoimmune issues in Shikoku as there is overlap between the relatedness of affected dogs. It is possible that the seizures we're seeing are a symptom of one underlying condition causing other issues (like lameness) in the breed. However, this is currently speculation and further study of affected dogs is needed.
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Treatment for seizures can be challenging and should be done with the guidance of a veterinarian. Sadly several affected dogs have had shortened lives because of these health problems.
HYPOTHYROIDISM
Currently, there are not a lot of known cases of thyroid problems in Shikoku, but with how closely related our dogs are and the fact that there have been a handful of diagnosed thyroid problems it is worth including. Additionally, thyroid problems do exist in Shiba and Akita.
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Testing can be done to check for Hypothyroidism by way of a blood test checking for autoantibodies, and it is recommended to re-test for this throughout the life of a dog.
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Hypothyroidism should be diagnosed and treated by a veterinarian and will likely require lifelong medication.
AUTOIMMUNE DISORDERS
There is at least one diagnosed case of Immune-Mediated Polyarthritis, which in time could be confirmed to be the pano-like symptoms some dogs experience throughout their life, which has been referred to as the "Shikoku Limp". There is no testing available to screen for these issues, which is why it's crucial for Shikoku owners to communicate with their breeders if they notice any issues in their dogs.
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No health screening is available for the potential autoimmune issues, and symptoms need to be present for diagnosis. Treatment varies based on the condition.
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CYSTINURIA
Recently discovered in Shikoku was a case of Cystinuria, and the breeder who saw it was able to test other dogs for it. Understanding of this issue in the breed, if it is widespread, and if the tests available will accurately detect it in Shikoku will come with time. It may be worth watching for Type I and II until we have more information.
EYE ISSUES
It has long been recommended to test Shikoku for genetic eye issues and abnormalities. Things to watch for but are currently uncommon in the breed include Persistent Pupillary Membranes, Progressive Retinal Atrophy, Distichiasis, and Entropion.
LYSOSOMAL STORAGE DISEASE
A couple of Shikoku have been diagnosed with Lysosomal Storage Disease. There is some overlap between the symptoms of LSD and some of the other conditions seen occasionally in the breed so it's possible they are connected. For instance, some of the symptoms of LSD could be mistaken for a seizure or the "Shikoku limp". More study of this issue needs to be done, and hopefully at some point there will be adequate screening for it.
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Cancer in Shikoku
It's often hard to say a breed is "prone to cancer" because when we look at domestic dogs as a whole, cancer is one of the leading causes of death, especially in older dogs. But cancer has become common enough in older Shikoku that I really want to make sure I don't gloss this one over. Especially since, while there is evidence that some breeds may be more prone to cancers (genetic predisposition) there is also a lot of evidence that diet, environment, and lifestyle can contribute to an individual's risks for cancer.
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The very simple summary is, I believe we should assume there is a risk for Shikoku getting cancer as they age. I think we can still expect a decent lifespan of 13-15 years or more, but the risk is there.
My opinion, based on years working in pet nutrition, speaking with veterinarians and nutritionists, and reading up on studies, is that diet can play a key role in cancer risk. Because of that combined with the risks of the breed, my recommendation is to feed Shikoku a fresh food diet, or at the very least add in fresh food inclusions whenever possible.
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When people ask me "what is the best kibble I can feed" I can give my recommendations, but at the end of the day it's not simply the ingredient quality or mix that is the concern with kibble, but that higher amounts of starches needed for extrusion and the multiple processing steps required. Some kibble companies have been able to minimize these, but even the best kibbles on the market tend to be highly inflammatory due to the intense processing required to make kibble.
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My intent by making these recommendations is not to make anyone feel guilty for feeding kibble, and I don't want anyone to think that because they've had a pet with cancer it's their fault because they fed kibble. I believe there are many factors that contribute to cancer risks, and diet just happens to be one that we can actually control. If feeding fresh food means I could potentially lower that risk even a little, I'll do it.
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Even the VCA includes recommendations for pets with cancer that support avoiding kibble - because kibble at a minimum typically needs to be 20% starchy binder ingredients:
"Tumor cells love carbohydrates. Tumors use carbohydrates to promote cancer cell growth, so high levels of carbohydrates in a dog's food will actually feed the tumor and starve the patient! Research suggests that dogs with cancer should eat a nutrient profile with no more than 25% carbohydrate on a dry matter (DM) basis. Unfortunately, the majority of canine adult maintenance formulations are far higher than that in carbohydrate content.
On the other hand, cancer cells have a difficult time using fat as an energy source, so foods that are relatively high in fat and low in carbohydrate may benefit dogs with cancer. In addition, higher levels of omega-3 fatty acids may exert an anti- tumor effect. While additional research is needed, it is recommended that canine cancer patients eat a ration with 25-40% DM fat and 5% DM or greater of dietary omega-3 fatty acids."
https://vcahospitals.com/know-your-pet/feeding-the-canine-cancer-patient
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Additional Links:
Hollings researchers studying whether popular dog foods are causing cancer
Health Guarantees
For all of the issues seen in Shikoku, there is, unfortunately, no way to guarantee that a dog won't inherit one of these diseases. Although health tests are available for some issues like hip dysplasia and hypothyroidism, these aren't DNA tests with straightforward "carrier" or "clear" results. There is a lot that we don't know about how these diseases get inherited, and it's not unheard of for a pair of dogs with passing health scores to produce offspring that end up affected by these diseases. We have also seen dogs with poorly rated hips go on to produce dogs with great hips.
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Does this mean we should skip health testing altogether since it's not a guarantee, or just breed all dogs no matter the results? Definitely not! It mainly means that breeding for improved health, especially in a rare breed with a small gene pool, isn't as simple as running some tests.
Improving health isn't something that will happen in one generation but is instead a progression. Ideally, if a breeder can have as many dogs from a litter health tested, rather than just the dogs they intend to breed, they can make more informed decisions about breeding. For a more detailed explanation of what this looks like for a breeding program (and anyone buying a puppy from said breeder), I highly recommend this blog post from October Setters.
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This is why for my breeding program I am prioritizing homes who are willing to have OFA evaluations done on hips once their dog is 2 years old, regardless of whether a dog is intended to be bred or will be a pet only.
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Screening a pet dog doesn't only benefit its breeder either - the sooner you catch an issue like hip dysplasia or luxating patellas, the sooner you can begin treatment and management that can ensure your dog can still live a normal, pain-free life!