You may have noticed that the ChinesecrestedOntario.com requires it's members to test their breeding dogs for hereditary problems. On this page you will learn what those tests are, and why we feel they are important to the health of our dogs.
CERF: CERF stands for Canine Eye Registry Foundation, and is a term used to describe a test performed by a board certified veterinary ophthalmologist (not your regular veterinarian). The ophthalmologist examines the dog's eyes in great detail, and makes note of any abnormalities or signs of disease. Because eyes can change gradually over time, CERF Certification is only valid for one year. CERF exams will show if the dog is affeted with PRA, Lens Luxation, Cateracts, Glaucoma, and many other diseases. It will not, however, tell us if the dog will develop these diseases in the future, or pass along those traits to their offspring. Therefore, it's important to have this test done yearly on all breeding dogs.
BAER: The Brainstem Auditory Evoked Response test is performed on dogs and puppies who are at least 35 days old. In cresteds, it is not uncommon to have a dog who does not have normal hearing in both ears. It is often difficult, or nearly impossible, to identify these individuals. While dogs who are unilaterally deaf can lead perfectly normal lives, they should not be used for breeding.
Patellar Luxation: The patella, or kneecap, is part of the stifle joint (knee). In patellar luxation, the kneecap luxates, or pops out of place, either in a medial or lateral position. There are varying degrees of Patellar Luxation, ranging from mild to severe. Severe cases can be corrected with surgery. Your regular veterinarian can check for this disease by manipulating the patella and reporting their findings with the OFA.
Progressive Rod-Cone Degeneration (prcd-PRA): Progressive Retinal Atrophy refers to a group of diseases that cause the retina of the eye to degenerate slowly over time. The result is declining vision and eventual blindness. PRA is not treatable, but is painless. There are at least two forms of PRA within the Chinese Crested. This DNA test will identify if the dog is CLEAR (has 2 normal copies of the gene), a CARRIER (has one normal copy and one mutated copy of the gene), or AFFECTED (has 2 mutated copies of the gene). At this time there is no test available for the alternate forms, so yearly CERF examinations are important.
Primary Lens Luxation (PLL): Primary Lens Luxation is a painful eye disorder, caused when the zonules which hold the lens in place break down. This DNA test identifies a dog as CLEAR (has 2 normal copies of the gene), CARRIER (has one normal copy and one mutated copy of the gene), or AFFECTED (has 2 mutated copies of the gene). Lens Luxation can also appear as a secondary condition (caused by cancer, glaucoma, or trauma), so yearly CERF examinations are still required.
The ChinesecrestedOntario.com encourages it's members, and all breeders, to test their breeding stock beyond what it considers 'required' testing. Without testing, it is nearly impossible to identify potential problems. What other testing is available?
Cardiac: Congenital heart diseases in dogs are malformations of the heart or great vessels. The lesions characterizing congenital heart defects are present at birth and may develop more fully during perinatal and growth periods. Many congenital heart defects are thought to be genetically transmitted from parents to offspring; however, the exact modes of inheritance have not been precisely determined for all cardiovascular
malformations. Cardiac exams should be performed after the age of 12 months, and only dogs foundphenotypically normal should be used for breeding. If present, heart murmurs are given a grade on a scale of 1 to 6.
Thyroid: Hypothyroidism, or under-active thyroid, is concern in all dogs. The disease has variable onset,
but tends to clinically manifest itself at 2 to 5 years of age. Development of autoantibodies at any time in the dog’s life is an
indication that the dog, most likely, has the genetic form of the disease. Dogs that are negative at 1 year of age may become positive at
6 years of age. Dogs should be tested every year or two in order to be certain they have not developed the condition.
Legg-Calve-Perthes (LCP): Legg-Calve-Perthes a disorder of hip joint conformation
occurring in both humans and dogs. In dogs, it is most often
seen in the
miniature and toy breeds between the ages of 4 months to a year. LCP results when the blood supply to the femoral head is
in avascular necrosis, or the death of the bone cells. Followed
by a period
of revascularization, the femoral head is subject to remodeling
collapse, creating an irregular fit in the acetabulum, or socket.
process of bone cells dying and fracturing followed by new bone
and remodeling of the femoral head and neck, can lead to