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Dog thyroid

Hypothyroidism in dogs, causes, symptoms and treatment of dog thyroid

Hypothyroidism, a disorder that is common to both animals and humans, is a condition in which the thyroid gland, an endocrine gland, is not able to produce enough thyroid hormone to meet the needs of the body.

The thyroid glands resemble or appear like two small lobes located in the neck region.

This is the gland that helps regulate metabolism in the body. If this gland is underactive, the metabolism of the dog decreases. Hypothyroidism in dogs can lead to a lot of complications in addition to gaining weight.

In most dogs, hypothyroidism is caused by the dog's own immune system. Hypothyroidism autoimmune thyroiditis is one of the main causes of this condition. In such a case, the body's own immune system begins to attack the thyroid gland, causing it to become less active. The thyroid gland does fend off some attacks.

However, eventually the gland loses its ability to keep up with such attacks. There is also a strong genetic predisposition to develop thyroid disorders. In addition to that there are several environmental factors like pollutants and allergies which also have a role to play in this disorder.

Canine hypothyroidism can often cause a lot of symptoms. For cold intolerance, the thyroid is blamed. For dog hair loss, the thyroid can be blamed again. Here are some of the common symptoms of hypothyroidism.

  • Lethargy in performing everyday activities.
  • Sudden and excessive weight gain without any considerable change in diet or exercise pattern.
  • Dry skin with patches of hair loss – especially on the tail.
  • Bacterial infections and thickening of skin.
  • Decrease of heart rate.
  • Intolerance towards cold temperatures.
  • Changes in behavior accompanied with seizures, anxiety and compulsive behavior.
  • Mood swings and depression.


The vet may ask for the medical history of the dog and examine all the other symptoms present. There will be a thorough physical examination of the dog. Blood test and hormone tests are conducted to ascertain the presence of the disorder. There are several tests done to test the functioning of the thyroid gland. Baseline T4 Test, Baseline TSH Test, Free T4 by RIA or radio immunoassay, Free T4 by ED or equilibrium dialysis, Baseline T3 Test, TSH Response Test.

Usually for the treatment of hypothyroidism, artificial thyroxine is injected into the animal. The dosage is increased periodically and the dog is examined regularly to note changes. There are also periodical blood tests to check whether any further adjustments are necessary.

  Submitted on June 1, 2010  

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