Diabetes mellitus is a disruption of the body's ability to use carbohydrates/sugars. Normally, certain cells in the pancreas produce the hormone insulin which regulates the uptake of sugars into cells throughout the body. In some forms of diabetes mellitus, the cells are dysfunctional and do not produce insulin, while in other forms insulin is produced but body tissues do not respond appropriately.
Genetics is only one of many factors that may be involved. In some dogs there seems to be a genetic predisposition to to the destruction by the immune system of the insulin-producing cells. In other dogs, less severe genetic-based changes in the cells may make the dog more susceptible to the development of diabetes mellitus - in association with another illness or obesity or exposure to certain drugs.
Hyperadrenocorticism, also known as Cushing's syndrome, is a common endocrine disorder in dogs. The clinical signs are caused by an excess of cortisol (the body's form of cortisone). This occurs because of increased secretion of cortisol by the adrenal glands in response to an abnormality in the pituitary gland in the brain, or because of a tumour in the adrenal glands themselves. Cushing's syndrome is more common in certain breeds, usually in dogs that are 6 years of age or older.
Hyperadrenocorticism may also occur in any dog that is being treated with excessive amounts of glucocorticoids. Glucocorticoid medication, often called steroids, is an important part of therapy in many different conditions in dogs.
Cholesterol is not metabolized properly by the body, which results in the dog having too much cholesterol in the blood stream. Also indicative is an underlying disease that raises the cholesterol level (for example, diabetes mellitus, kidney disease, liver disease, or hypothyroidism). Obesity itself leads the body to produce excessive amounts of cholesterol.
Hypoadrenocorticism (Addison's disease) is a rare but serious disorder of the endocrine system caused by the gradual destruction of the cortex of the adrenal gland, most commonly by the body's immune system . (Cancer, hemorrhage, or certain drugs can also cause adrenocortical destruction.) The result is a decrease in production of glucocorticoids and mineralocorticoids - adrenal hormones that are necessary for a wide range of body functions. Deficient production of these hormones produces a diverse array of clinical signs, many of them vague.
An autoimmune, endocrine disease in which the amount of thyroid hormones produced are abnormally low. This condition is more prevalent than an overactive thyroid (Hyperthyroidism).
An autoimmune, endocrine disease causing inflammation and destruction of the thyroid gland, which becomes infiltrated with lymphocytes (type of white blood cells) and leads to hypothyroidism.
An autoimmune inflammatory disease of the thyroid gland. (See Hypothyroidism and Lymphocytic Thyroiditis.)
For more information on thyroid disease, please follow this link:
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"Just because some people select and breed dogs now does not mean that the original dogs were created that way. Looking closely at the behavior of wolves, and understanding the biology of a wild animal, I don't think there is a ghost of a chance that people tamed and trained wild wolves and turned them into dogs. I think a population (at least one) of wolves domesticated themselves."
Common breeding tests for the Shetland sheepdog include eye tests, hips/elbows/knees, thyroid panels and sometimes vWD certification.
The only breeding test that can 100% identify whether or not your puppy has any one of the genetic diseases listed above is the vWD-DNA test. However, this disease is very rare in shelties, affecting 1% of the breed's population.
Eye exams certified by the Canine Eye Registration Foundation (CERF), which reports any eye abnormalities in the breed due to hereditary disease. In Shetland sheepdogs, the two main concerns are Collie Eye Anomaly (CEA) and Progressive Retinal Atrophy (PRA).
This is done through x-rays evaluated by three specialists at the Orthopedic Foundation for Animals (OFA) or PennHip (University of Pennsylvania) and is used to detect the presence of hip dysplasia. OFA will do preliminary evaluations on dogs under two years of age, but will only certify dogs over two years of age. Dogs that have preliminary certification done through OFA, should have x-rays resubmitted because they are not given a permanent rating and often times, the rating can change for better or worse.
This test is used to detect autoimmune thyroid disease. Autoimmune thyroiditis can be influenced by environmental changes, such as excessive heat; or hormonal changes, such as aging. A thyroid test is a blood test and should be a complete panel that includes Total T4, Free T4, Total T3, Free T3, T4 auto antibodies, T3 auto antibodies, TSH (thyroid stimulating hormone), and TgAA. A thyroid test is not always a conclusive diagnosis.
vWD, Factor III is a bleeding disorder in the Shetland sheepdog. The DNA test determines whether a dog is affected (two genes), a carrier (one gene), or clear of the disease. According to vetGen, affected shelties are very rare: (7% carrier-status; 1% affecteds as of January 26, 2005). Most breeders will not introduce the affected gene, but those that are breeding affected lines can easily & effectively manage its safe elimination through prudent vWD-DNA testing.
Control of Canine
by George A. Padgett, DVM
Genetics of the Dog
by Malcolm B. Willis
Home Veterinary Handbook
by James M. Giffin, MD &
Liisa D. Carlson, DVM
Genetic Aspects of
Edited by Ross D. Clark, DVM &
Joan R. Stainer
Disorders Database (CIDD)
Alice Crook, BSc, DVM
Brian Hill, DVM, MS, DACVIM
Sue Dawson, BA, PhD
Amatras are breeders dedicated to focusing on longevity, health, temperament, structure, brains and beauty. Dogs are added to the program with these qualities only and bred only to improve each trait through each successive generation.
© Amatras Shetland Sheepdogs