Known diseases of Nova Scotia Duck Tolling Retrievers
Tollers are known to have several diseases, some of which are known to be hereditary and some are assumed to be hereditary. The majority of the diseases also appear in other retriever breeds, so the Toller is not, in fact, unhealthier than other retrievers but not healthier either. When breeding dogs, one must pay special attention to hereditary diseases and how to avoid them. Thus, it is extremely important to have each dog examined (hip and elbow examination and eye examination) even though the dog would not be used for breeding. In addition, it is vital to let the breeder and the breeder committee know about the dog's possible diseases. By being open and honest, we can have an effect on breeding and promote the birth of healthy Tollers.
HIP DYSPLASIA refers to a malformed hip socket. Tollers are known to have hip dysplasia to some extent. It is a polygenic disease, that is, more than one gene is involved in the disease. Diagnosis is made by x-ray. Mild cases do not cause any symptoms but in more serious cases, the hip dysplasia can cause the dog to be in severe pain, especially at an older age. Only Tollers with healthy hips should be used for breeding, as a dog with badly formed hips has more cases of hip dyplasia in its offspring than a dog with normal hips. However, feeding and exercise also affect the development of hips.
ELBOW DYSPLASIA refers to the abnormal development of the elbow. This disease is significantly more common with other retrievers than Tollers. So far, only a few mild cases have been diagnosed. However, it is recommended that the elbows of Tollers are x-rayed because elbow dysplasia can, in the worst case, disable the dog.
Hereditary eye diseases
PRA (progressive retinal atrophy) occurs in every line of Tollers, so affected dogs and carriers are likely to appear in the pedigree of each Toller. The mode of inheritance is suspected to be simple recessive, which means that both parents of an affected dog are carriers of the gene. PRA is a disease that destroys the cells and blood vessels at the back of the eye, leading eventually to the blindness of the dog. Early in the disease, affected dogs are nightblind, they lack the ability to adjust their vision to dim light and later their daytime vision also fails. Most often PRA is diagnosed when the dog is 5-7 years old but it can start at an earlier age as well. However, the progressive blindness may not be noticeable for some time. All dogs' eyes should be examined regularly.
To fight PRA, a test has been developed which examines whether the Toller is free from PRA, i.e. normal (pattern A), PRA carrier (pattern B) or PRA affected (pattern C). With the help of this test we can at first prevent the birth of affected dogs and in the long run, reduce the number of carriers in the breed. Thus, all Tollers that are used for breeding should be tested in order to prevent the birth of PRA affected dogs.
There are also other eye diseases that cannot be diagnosed with the PRA test mentioned above. These include RD (retinal dysplasia) and HC (hereditary cataract).
Autoimmune diseases refer to diseases in which the body's own defence mechanism fails and starts to attack its own system. It is not clear to what extent these diseases are hereditary but apparently the predisposition to get the disease is hereditary. It is assumed that Tollers have a kind of immunological weakness which can lead to the disease breaking out. Environmental factors also seem to have an effect and therefore different stressful situations can trigger the disease. Autoimmune diseases occur in every line of Tollers. The dogs that get the disease are usually young, almost all known cases have been diagnosed before the age of two years.
A/M (arthritis/meningitis) causes high fever, stiff movement, stiffness in the neck and difficulties in eating and drinking. It is usually diagnosed in puppies aged between 6 and 9 months. The symptoms vary individually and the disease can be diagnosed by taking a sample from the spinal cord. The used medication is cortisone.
HYPOTHYROIDISM is the result of impaired production of thyroid hormone. The symptoms can include lethargy, scaly skin and dull coat. In addition, the disease may cause muscle wasting, infertility, hair loss and weight gain. It can be treated with medication.
HEMOLYTIC ANEMIA is a condition in which the immune system destroys red blood cells. The symptoms include weakness, lethargy and pale gums. Vomiting and bruises can also occur. The disease is treated with cortisone.
SLE (systemic lupus erythematosis) causes symptoms that resemble to great extent other autoimmune diseases. The disease is difficult to diagnose. The diagnosis is made from blood and urine samples. SLE is often treated with both antibiotics and cortisone.
ADDISON'S DISEASE (hypoadrenocorticism) is a result of the outer layer of the adrenal glands failing in its secretion of hormones. Typical symptoms include depression, vomiting and diarrhea. The dog may also go into acute adrenal crisis and have severely slowed heart rate, shock, dehydration and weak pulse. The symptoms of the disease are unspecific and their strength varies individually. The disease is diagnosed with a blood test. With the help of medication the dog can usually lead a normal life.
LYMPHEDEMA usually causes swelling of the joints of hind legs. The dog may walk with a limp and also have a fever. The condition may, however, be so mild that it goes unrecognised. The diagnosis is made by excluding other possible diseases.
EPILEPSY causes repeated seizures. The disease can either be hereditary, traumatic or caused by a foetal disturbance or during birth.
Other diseases that occasionally occur in Tollers include heart diseases, liver and kidney diseases, cancer and chondrodysplasia.