Description: An endocrine condition in which there is an insufficient production of thyroid hormone. This is often caused by autoimmune responses and typically occurs in middle-aged dogs. Hypothyroidism is rare in cats.
Symptoms: Symptoms are usually non-specific, but may include lethargy, obesity, hair loss, and high cholesterol.
Diagnosis: Diagnosed via blood test.
Treatment: Hypothyroidism is easily treated by administration of a synthetic thyroid hormone called thyroxine. Doses vary by the animal's weight and severity of the case. The dog will need regular administration of the hormone for the rest of its life.

Cost: $8-$20/month for medication plus the cost of bi-annual blood tests

Breeds prone to Hypothyroidism include: