Health Testing for CHIC Certification Helps to Promote Well-Being in Dalmatians
Most Dalmatian enthusiasts are proud to tell you that their breed is a healthy, long-lived one. The Dalmatian Club of America (DCA) plans to keep it that way.
Health testing lies at the crux of keeping Dalmatians healthy, say DCA officials. This is why the national parent club supports health clinics at specialty shows and participates in the Canine Health Information Center (CHIC). Sponsored by the Orthopedic Foundation for Animals and the AKC Canine Health Foundation, CHIC provides a centralized canine health database that contains health testing information about individual dogs as well as a DNA Bank Repository.
“Overall, the Dalmatian is an extremely healthy breed,” says DCA president Meg Hennessey of Garden Prairie, Ill. “CHIC allows breeders to research the health status of dogs they are considering breeding, as well as their parents, siblings and offspring.”
When DCA joined CHIC in 2004, the parent club determined that health tests should be submitted for hearing, eyes and hips in order for Dalmatians to receive a CHIC number. In 2010, DCA made eye tests an elective test along with thyroid evaluation.
“Originally, other than the hearing test, it was a challenge to determine what tests should be required for a Dalmatian’s CHIC certification. This is a really healthy breed,” says Charles Garvin, M.D., of Marion, Ohio, president of the Dalmatian Club of America Foundation (DCAF) and member of the board of directors of the American Kennel Club and the AKC Canine Health Foundation.
Garvin and Hennessey are advocates of health testing for CHIC certification. They believe the two mandatory tests, which screen for congenital deafness and hip dysplasia, combined with an elective test for eye diseases or hypothyroidism, cover the spectrum of possible health threats in the breed.
Hennessey was instrumental in building the Dalmatian DNA Bank Repository at CHIC. She and her husband, Mike, traveled the country in 2010 to assist affiliate Dalmatian clubs with blood draw clinics that were subsidized by DCA and DCAF. The DNA from these blood samples, along with genealogic and phenotypic information, was banked for future use by researchers to help them better understand genetic health conditions affecting the breed.
Here is a review of the required and elective health tests for Dalmatians.
A CHIC number does not mean a dog received normal test results, but rather, that the breed-specific tests were performed and the owner elected to have the results publicly available.
Testing for Congenital Deafness
Brainstem auditory evoked response (BAER) tests are the most reliable way to check hearing in dogs. The testing uses computers to record electrical activity of the brain in response to sound stimulation. During the test, a computer produces a stimulus check that is directed into the dog’s ear through a foam microphone. Responses in the brain waves, which are collected through small electrodes, are averaged to determine the results.
BAER testing, which typically takes 10 to 15 minutes, is not painful and can be conducted on dogs as early as 6 weeks of age. The incidence of deafness in Dalmatians is the highest of nearly 100 breeds that suffer from congenital deafness, with as many as 29.9 percent of Dalmatians born deaf in one or both ears. Because it can be difficult to detect dogs that are unilaterally deaf, or have no hearing in one ear, BAER tests should be performed on adult Dalmatians being considered for breeding.
“We used to think all affected Dalmatians were bilaterally deaf, or deaf in both ears,” Hennessey says. “When the BAER test was introduced in the mid-1980s, it showed that some dogs are unilaterally deaf and have functional hearing in the other ear. Although dogs with unilateral hearing will not pass the hearing test, they still can live a normal life.”
Research has shown that the chance of producing deaf offspring almost doubles when breeders breed dogs that are bilaterally or unilaterally deaf. Studies also have shown that Dalmatians with blue eyes are more likely to produce deaf puppies.
Deafness in Dalmatians relates to coat color, which also contributes to the breed’s unique appearance. An underlying coat of black or liver is covered with a brilliant white coat, which comes from the extreme piebald gene. It is this gene that is linked to deafness.
Researchers believe Dalmatians develop deafness because of the extreme piebald gene’s suppression of pigment-producing cells that are necessary to the health of the stria vascularis, the vascular bed lining the outer wall of the cochlear duct. This subsequently damages the cochlear and sensory hair cells that are necessary for hearing.
DCA recommends that breeders do not breed deaf dogs, including those that are unilaterally deaf, or dogs with blue eyes. The parent club also recommends that breeders track parents, grandsires and granddams, and great-grandsires and great-granddams to increase awareness of deafness in their bloodlines.
Learning the Risk of Hip Dysplasia
Canine hip dysplasia (CHD) is caused by abnormal hip development that worsens from extreme wear to joint cartilage during weight-bearing exercise. Affected dogs have a poor fit between the femoral head and acetabulum that allows for loose movement or laxity of the hip joint. Eventually, that wear develops into osteoarthritis or degenerative joint disease, which can be severely painful and cause lameness.
Because the condition worsens over time, many dogs do not show signs until they are older. Signs of hip dysplasia include abnormal gait, bunny hopping when running, thigh muscle atrophy, pain, low exercise tolerance, reluctance to climb stairs, and an audible click when walking.
Hip dysplasia occurs more commonly in large breeds, like Dalmatians, compared to small- and medium-size breeds. Due to the heritability of this degenerative disease, dogs that are dysplastic should not be bred. Testing to determine a dog’s risk of developing hip dysplasia has helped to lower the incidence rate in Dalmatians, with only 4.4 percent of dogs tested using the Orthopedic Foundation for Animals (OFA) method being dysplastic.
Accurate screening is critical in determining whether a dog is susceptible to CHD. CHIC accepts hip evaluations using methods developed by OFA, Ontario Veterinary College (OVC) and PennHIP.
The OFA method provides radiograph views of a dog lying on its back in dorsal recumbency with rear limbs extended and parallel to each other. The stifles (knees) are rotated internally, and the pelvis is symmetric. Preliminary testing can be done in dogs as young as 4 months old, but these dogs should be re-evaluated at 24 months of age. Three radiologists review the radiographs separately. Dogs receiving excellent, good and fair ratings are considered within the normal range and receive OFA numbers.
The OVC method of hip evaluation is patterned after OFA, except one radiologist, rather than three, reviews the radiography. Preliminary results are provided for young dogs, and dogs 18 months of age and older can be evaluated to receive an OVC number.
Using the PennHIP method, hip joint laxity is assessed based on three separate radiographs. The radiographs present: the distraction view, compression view and hip-extended view. The hip-extended view is the conventional radiographic view used to evaluate the integrity of the hip joint, and the other two views provide information to help assess joint laxity.
Annual Eye Examination Elective
Eye diseases affecting Dalmatians include progressive retinal atrophy (PRA) and iris sphincter dysplasia, which is also known as iris hypoplasia. Eye examinations for CHIC certification must be done by a veterinarian who is board-certified by the American College of Veterinary Ophthalmologists. Annual eye exams are required to maintain CHIC certification.
“There is very little PRA in Dalmatians,” says Garvin, an ophthalmologic surgeon who is president and chairman of a large multispecialty group practice. “Although iris dysplasia is more common, it is far less problematic and doesn’t affect a dog’s vision as PRA does.”
Progressive retinal atrophy is an inherited condition that causes degeneration of the rod cells of the retina and can lead to progressive vision loss. Although not painful, it affects both eyes simultaneously.
Iris sphincter dysplasia is the result of poorly developed iris sphincter muscles. Owners notice affected dogs often squinting in sunlight due to their pupils not properly contracting in bright light. The disorder exposes the interior of the eye to ultraviolet light, which can cause cataracts and retinal damage as dogs age.
Thyroid Examination Elective
Although hypothyroidism is the most common endocrine disorder in dogs, it doesn’t occur commonly in Dalmatians. Dogs suspected of having hypothyroidism should be tested to confirm they have the inherited disease as the clinical signs resemble other conditions, such as skin disorders and certain reproductive and neurological problems.
Hypothyroidism is the end stage of lymphocytic thyroiditis or autoimmune thyroid disease, a condition that occurs when a dog’s autoimmune system attacks and destroys the cells of the thyroid follicles, the portion of the gland that makes thyroid hormones. Dogs typically are born with normal thyroid function, but by the time they are 4 to 6 years of age the disease is apparent, often after they have already been bred.
The thyroid, located on the throat below the larynx, produces the hormones thyroxine (T4) and triiodothyonine (T3), which control metabolism and the oxygen consumption of almost every tissue in the body. Dogs with hypothyroidism have sluggish, below-normal metabolic rates. Clinical signs include depression, lethargy, weight gain, dry skin, and a low tolerance for cold.
In order for a dog to receive CHIC certification, testing must be performed at an approved laboratory. For continued certification, a dog must be tested at 2, 3, 4, 6 and 8 years of age. An assessment of thyroid function is based on three variables:
- The total or free thyroid hormones, T4 and T3, in the circulation, which gives insights on hormone production from the thyroid gland
- The thyroid stimulating hormone (TSH), which indicates the pituitary gland is signaling for an increase in the production of thyroid hormones from the thyroid gland
- Thyroid autoantibodies (TgAA), a marker for lymphocytic thyroiditis
Treatment for hypothyroidism involves giving an affected dog a veterinarian-prescribed synthetic version of the T4 hormone, called thyroxine, and having blood tests taken periodically throughout a dog’s life to monitor the supplemented levels. Although untreated dogs rarely die from the condition, they are at greater risk for infection and obesity, which can strain the heart. Dogs that test positive for the disorder should be removed from breeding programs.
Helping to Shape a Healthy Future
Health testing unites Dalmatian breeders with a common cause to stamp out inherited diseases and help shape a healthy future for the breed. “I think most breeders recognize the importance of health testing their breeding stock and puppies,” Garvin says. “It is good for purebred dogs to be tested, and it also gives a pet buyer the best chance of getting a healthy dog.”
Most Dalmatian enthusiasts also probably share Hennessey’s view. “Dalmatians are the most wonderful breed on earth. I can’t imagine not having one in my life,” she says.
Purina appreciates the support of the Dalmatian Club of America and particularly Meg Hennessey, president, and Dr. Charles Garvin, president of the DCA Foundation, in helping to identify topics for the Purina® Pro Club® Dalmatian Update newsletter.
CHIC Requirements for Dalmatians
The Canine Health Information Center (CHIC) provides a database with health testing information about individual dogs. A CHIC number does not imply normal testing results, but rather, that the breed-specific tests were performed and the owner opted to make the results publicly available. Breeders can use the health test information (caninehealthinfo.org) to make informed breeding decisions and ultimately help better the breed.
Required health tests for Dalmatians determine these conditions:
Congenital Deafness, based on a BAER (brainstem auditory evoked response) test using:
- OFA (Orthopedic Foundation for Animals) evaluation or
- GDC (Genetic Disease Control) evaluation
Hip Dysplasia, using:
- OFA evaluation or
- OVC (Ontario Veterinary College) evaluation or
- PennHIP (University of Pennsylvania Hip Improvement Program) evaluation
Elective health tests include one of the following:
- Hypothyroidism, based on an OFA thyroid evaluation or
- Progressive retinal atrophy or iris sphincter dysplasia using an OFA eye or CERF (Canine Eye Registry Foundation) eye examination. Both tests must be performed by a veterinarian who is board-certified by the American College of Veterinary Ophthalmologists.
Test results from OFA and CERF databases automatically are shared with CHIC at no cost to owners. The Dalmatian Club of America Foundation subsidizes the cost of registering a litter’s BAER test results, so there is no cost to owners. Results from other sources require a one-time fee of $25 a dog.