Low Thyroid Function in Dogs

Thyroid Function and Hypothyroidism

The thyroid is a small gland that sits below the dog's voice box in the dog's neck. The thyroid gland is responsible for producing thyroid hormones that regulate the dog's metabolism. When a dog suffers from low thyroid, or hypothyroidism, the thyroid gland produces lower amounts of the thyroid hormone thyroxine and subsequently causes the dog's metabolism to slow down. Thus, the thyroid is a very important gland and needs to be working correctly for the dog's health.

Because the thyroid hormone affects so many systems, the symptoms of low thyroid can be varied. Not all dogs with low thyroid will show symptoms. Common symptoms include weight gain, hair loss or unhealthy looking coat, cold intolerance, aggression, infertility, slow heart rate, inability to exercise long, depression, mental dullness, constipation, diarrhea, skin disorders and more.

Of dogs that have hypothyroidism, 95 percent suffer from a type of hypothyroidism caused by an autoimmune disorder where the immune system attacks the thyroid gland, according to PetEducation.com. Other forms of hypothyroidism can be caused by cancer, tumors, iodine deficiency, medications, dwarfism, surgical removal of the thyroid, radiation therapy and idiopathic follicular atrophy, a degenerative condition of the thyroid.

Any breed or mixed breed may have low thyroid; however, certain breeds have a greater occurrence than others. These include English setter, boxer, Brittany spaniel, giant schnauzers, Dalmatians, golden retrievers, Irish setters, Doberman pinschers, dachshunds, miniature schnauzers, cocker spaniels, and Airedale terriers.

There are several tests to determine if your dog is suffering from hypothyroidism. The common tests your veterinarian may perform on your dog may include blood tests that determine various thyroid hormone levels including T3, T4, and thyroid stimulating hormone. Your veterinarian may also have a CBC (complete blood count), urinalysis, biochemical profile or even X-rays done as part of the diagnostic process.

Once your veterinarian diagnoses your dog as hypothyroid, your veterinarian may prescribe synthetic thyroid hormone (thyroxine). This is usually given in pill form for the rest of the dog's life.