Pond Hollow Chesapeakes

Health Issues

The Chesapeake Bay retriever is a generally healthy breed of dog. The following information described is mentioned because these conditions have been reported in the breed. This does not mean that the majority of the dogs in the breed suffer from these problems. Most conscientious & concerned breeders employ all or some of the listed health testing procedures. These tests are not inexpensive and are part of the cost to rearing puppies. A cheaper puppy to buy may very likely in the long run "cost" much more in care and emotional pain to the owner. The price of a puppy is probably the cheapest part of dog ownership.

OFA certification for hips and elbows (other countries have different schemes); CERF for eye diseases (annual checks to age 7 or 8) and DNA testing for the PRA gene are the main health testing done. Additionally DNA testing for EIC (see below) and DNA susceptibility for DM (see below) as well as cardiac & thyroid testing are sometimes done.

Hip dysplasia, and to a lesser extent elbow dysplasia, do occur in the breed. While neither condition is totally genetic, OFA certified dogs produce a higher percentage of correct hip and elbow conformation. Eye problems that crop up are: cataracts, entropion and very occasionally retinal folds & glaucoma. Not all cataracts are inherited but only an experienced veterinary ophthalmologist can tell the difference. Conscientious breeders check their dogs' eyes on a regular basis. Another eye disease PRA is rarely seen anymore. There is a DNA test to determine the genetic makeup of a dog for this defect prior to breeding. See Optigen Website. Buying a puppy without knowing the PRA DNA status of the parents is taking an unnecessary risk. The American Chesapeake Club maintains a list on its web site of PRA DNA tested dogs. NONE of the health registries can or will tell a breeder that a dog failed testing for any certification due to non-genetic reasons. Don't let yourself be fooled. See our Links for OFA (hips & elbows), CERF (eyes) & ACC (PRA DNA) web sites to verify information.

EIC is a syndrome of exercise intolerance and collapse (EIC) that has been recognized in Chesapeakes. The disease is relatively uncommon in the breed and a genetic test is now available. This disease is a simple recessive gene problem-meaning that ONLY ONE gene is involved in producing the disease. Many CBRS were tested in the research phase of the DNA test's development and the incidence of the gene in the breed is extremely low. All of our breedings are done so that no affected offspring will be produced.

Affected dogs can tolerate mild to moderate exercise, but 5 to 20 minutes of strenuous exercise induces weakness and then collapse. Severely affected dogs may collapse whenever they are exercised to this extent - other dogs only exhibit collapse sporadically and the factors important in inducing an episode have not yet been well established. The first thing noted is usually a rocking or forced gait. The rear limbs then become weak and unable to support weight. Many affected dogs will continue to run while dragging their back legs. In some dogs this progresses to forelimb weakness and occasionally to a total inability to move. Some of the dogs appear to be uncoordinated and have a loss of balance, particularly as they recover. Some will appear stunned or disoriented during the episode.

DM Degenerative Myelopathy has been reported in the breed. DM is the same as the ALS disease in humans. There is ongoing research for more answers to the DM/ALS problem at the University of MO and elsewhere. There is no cure or definitive test for this disease at the present time. DM is a POLYGENIC disease-meaning more than one gene is needed to produce the disease. It occurs late in a dog's life often after age 10. However, there are several other problems that can cause DM like symptoms, so professional care is needed to eliminate those possibilities. Less than 1% of Chesapeakes develop the disease each year-obviously not a common problem.

While there is a DNA test for ONE of the genes that is associated with the disease, it is a susceptibility test ONLY. It does not mean that a dog will be affected with DM simply due to the presence of the one gene tested for. Why ? The reason is that other genes still not identified MUST be there also to cause the disease. There is NO test for determining if a dog has all the genes needed to cause the disease. In 35 years, we have never owned or used for breeding any dog affected with DM like symptoms. We follow our puppies far beyond the day you take your pup home. Being serious breeders, we are committed to breeding the TOTAL dog and maintaining genetic diversity so vital to any breed's well being.

Please read the information below from Dr. Jerold Bell of Tufts University. Our breeding plans are based on the information and goals outlined below.

Dr. Bell is a practicing veterinarian as well as Clinical Associate Professor of Genetics at Tufts Cummings School of Veterinary Medicine in MA. Dr. Bell received his BS from Michigan State and his DMV from Cornell University, NY State College of Veterinary Medicine in 1982. His areas of interest are Genetic Disorders, Epidemiology of Defective Genes in Purebred Populations, and Breed Improvement/Breeder Education.

 

Dr. Bell states:

"There are susceptibility genes that can be directly tested for (direct mutation-based test), but they are NOT absolutely causative for a disease state. Presence of the gene is considered a risk factor for the disease. The DM test is a direct mutation-based test for a susceptibility gene. A genetic mutation has been found that MUST BE PRESENT in order to have the disease. All clinically confirmed dogs with DM (from all breeds, including cross-bred dogs) have two copies of the defective gene. However, other factors must also be present to cause a dog with two copies of the defective gene to be clinically affected with degenerative myelopathy."

"The DM test is for a recessive mutation that controls part of the inheritance of the disease."

"For those dogs where closely related dogs with clinical DM have not been identified: The susceptibility gene should be looked at as a fault, just as other behavioral, conformational, or performance faults. When deciding on the breeding quality and prospective mate of any dog, their positive traits and their faults need to be weighed and considered.Breeding toward DM normal dogs is a long-term goal; however quality dogs should not be discarded based on a single testable gene."

"In order for the breed to move away from the disease, offspring testing normal for the DM susceptibility gene should be preferentially selected between comparable quality offspring to represent the next generation of breeding dogs."

Question: Is the result of this test for one gene for DM enough to advise breeders to only breed only Carrier and At-Risk dogs to only normals?

"No. While this recommendation guarantees that no DM affected dogs will be produced, it also requires that all matings be conducted with at least one member of a class of 42% of your gene pool. This significantly skews the gene pool in their direction, and reduces the influence of almost 60% of the breed's gene pool. For a disease that affects less than one in one-hundred Chesapeake Bay Retrievers, this severe a restriction on breeding will significantly limit the breed's genetic diversity."

Question: Should carrier to carrier breedings be avoided even if there are no reports of DM having occurred in the pedigree?

"Breeding two carriers of the DM susceptibility gene together (where no clinically affected close relatives are known) does produce a low risk for producing clinically affected offspring. This should be weighed as a fault that must be superseded by the positive traits of the two dogs being considered for breeding."

Question: Genetic diversity seems to be very important in maintaining overall health in a breed. In a nutshell, what is genetic diversity? How can we increase it and still breed away from DM?

"Genetic diversity is the total variation in types of genes between individuals in the gene pool. Breeds have closed stud books. Because of this, genes can be lost to the breed by eliminating segments of the gene pool, and there are no "new dogs" to infuse new genes. For most breeds, this does not cause a problem if the breed is relatively healthy with a large breeding population."

Dr Jerold Bell, Tufts University

 

Seizures (genetic & non-genetic epilepsy) can occur in the breed. This is a multiple (polygenic) gene problem with a variable expression (occurrence) factor. Like many polygenic disease, the parents are often normal. Seizures also occur from many non-genetic sources, so seizures are particularly difficult to deal with for the breeder. Testing to determine whether genetic or not can be extremely expensive. However, idiopathic (inherited) epilepsy normally occurs slowly and usually by age 3. There are also medications such as heartworm supplements that lower the seizure threshold in some dogs. There is NO certifying organization for this condition. No one line of Chesapeakes is known to be free of the potential for seizures.

There are other conditions that can be encountered: thyroid conditions, skin problems due to allergies, and stifle (knee) problems. Not all of these are necessarily genetic conditions so it is important to be in touch with the breeder and get informed veterinary care. Correct care of the dog in terms of proper type of exercise and diet also play an important role in maintaining a healthy dog. Like any living creature, dogs in general, not just Chesapeakes, are subject from time to time to various odd diseases much like humans get. Cancer is not a problem in the breed as it is in some other dogs like-Bernese Mountain dog, Golden retriever and Flat-Coated retriever. The normal lifespan is 12 yrs.

 

DYANE BALDWIN          4308 MANNSVILLE RD, NEWPORT PA 17074          717.319.8749          PONDHOLO@PA.NET