A Great Dane could possibly suffer a disease called hypothyroidism. Aside from Great Danes, this disease is suffered by most mid-size to large breeds such as Boxers, Labrador Retrievers, Rottweilers and German Shepherds.

Just like the human body, a dog, has various endocrine glands that secrete chemical substances called hormones. The thyroid gland, the two small butterfly-shaped lobes located in the neck is the master gland. This gland has a number of functions but is well known for regulating the dog's metabolic rate. If the thyroid gland is malfunctioning, every cell in the body is affected.

Hypothyroidism occurs when the thyroid gland malfunctions and unable to produce not enough hormone called thyroxin. As stated, this gland is important in regulating the dog's metabolic rate. It controls the growth and development and maintains normal protein, carbohydrate and lipid metabolism. The disease usually occurs to dogs two to six years of age. While it has been said that thyroid disorders are inherited, diet and environmental factors such as pollutants and allergies are also culprits for the occurrence of this disease.

One of the most common signs of hypothyroidism in your Great Dane is weight gain without an apparent gain in appetite. Pretty ironic, isn't it? Lethargic behaviors, slow heart rate, chronic ear infections, depression and behavioral changes can also be seen in a dog with hypothyroidism. He may also suffer from skin problems such as dry skin, bacterial infection of the skin as well as hair loss and discoloration or thickening of the skin where hair loss has occurred.

Hypothyroidism is diagnosed through physical examination wherein the veterinarian will be looking for clinical signs of the disease. The vet will also be asking questions about your dog's health, behavior and even history. If hypothyroidism is suspected, blood test such as T4, T3 and TSH test should be done. T4 test is the most common in which blood sample is drawn and then tested. Low level of T4 indicates problem in the thyroid. T3 is similar to T4 but is less accurate when used during the early stage of the disease. To ensure accuracy, T3 test should be used together with T4 test or TSH test. TSH is used when the results of T3 and T4 tests seem inaccurate.

The disease is treated with synthetic thyroid hormone called thyroxine. Dosage varies depending on the severity of the condition, the dog's weight, blood samples and the dog's response to the drug. Once a dog is placed on thyroxine medication, it should be given throughout the dog's life. Tests should be done periodically to assess the efficacy and make any adjustments if needed.