Here is a little known fact. January is Thyroid Awareness Month.

Yep, there is even a web site for it: www.thyroidawarenessmonth.com. This site focuses on human thyroid diseases, but dogs and cats suffer from thyroid gland issues as well.

In fact, it is the most common hormone imbalance in cats and dogs.

Let's take Jacob, for instance. Jacob, a mellow 4-year-old black Labrador mix, gained three or four pounds every time he came in to Bees Ferry Veterinary Hospital for an annual checkup or ear infection.

His owners barely noticed, because his weight gain was fairly gradual, but as his veterinarians, we noticed the weight gain.

At first we simply cautioned about treats and encouraged more exercise, but soon it became clear that something else was wrong.

Jacob's owners were diligently controlling his food intake, but Jacob just wouldn't exercise.

As he was nearing 100 pounds (he would have looked great at 75), family and friends argued that he was just too heavy to run and romp.

We confirmed that his excessive weight was exacerbating some arthritis in his hips, but a 4-year-old Labrador should be full of energy.

It was time for some blood tests to look for underlying diseases or hormonal deficiencies.

It turned out that Jacob's blood counts and enzymes were all in good order, but his thyroid levels were remarkably low.

Jacob was hypothyroid, meaning that his thyroid gland was not producing enough thyroid hormone.

The interesting thing about Jacob was that he had a very healthy looking hair coat.

Almost all hypothyroid dogs that we see have unhealthy skin and hair loss. Only about 50 percent of them are overweight or listless.

Some even less common indications of hypothyroidism from which Jacob was spared include anemia, heart problems, nerve related issues and even some eye diseases.

Jacob was started on levothyroxine, which is a thyroid supplement that is commonly used in humans and dogs.

The interesting thing is that dogs take much higher doses than humans.

A dog the size of Jacob would have to take several human tablets twice a day, making it much more expensive than the veterinary version, so we put Jacob on the dog supplement and let his body adjust to the new medicine for two weeks before we retested his thyroid level.

Jacob was already losing weight and he was much more active.

In fact, he was actually hyperactive.

His blood test showed that his thyroid levels were a little bit too high, so we reduced his dose a little bit and checked again in two weeks.

This time, his levels were perfect.

He was still losing weight and was back to chasing the ball like a puppy, but he was no longer hyperactive.

Jacob will be on medication twice a day for the rest of his life, and he will need close observation by his veterinarian with blood tests once or twice a year, but he will finally be a normal active Labrador mix.

Cats, on the other hand, tend to have overactive thyroids, so think of exactly the opposite symptoms from those displayed by Jacob. Hyperthyroid cats eat and drink a lot but stay thin or lose weight.

Hyperthyroid cats are usually older.

Instead of a shrinking thyroid gland, they have a growing one than can sometimes be palpated by your veterinarian.

Controlling an animal with a hyperactive thyroid is a lot more complicated than simply giving a supplement.

Medication to stop production of thyroid hormone is usually the initial treatment.

But cats hate to take medications.

Surgery to remove the affected gland or radioactive iodine therapy to destroy the thyroid tissue is usually needed to treat a hyperthyroid cat in the long run.

I'll talk about this in another issue, but, in the mean time, be sure to let your veterinarian know if your dog is showing signs of hypothyroidism or if your cat is eating like a pig; and happy Thyroid Awareness Month!

(Dr. Katherine A. Saenger, DVM, owns Bees Ferry Veterinary Hospital and Boarding Kennel (www.beesferry.com) and is a former board member of the Charleston Animal Society (formerly John Ancrum SPCA.) If you have questions about pet behavior or health, or suggestions for column topics, e-mail her at vetsaenger@bellsouth.net, and watch the column in coming weeks for her responses. See more columns at www.moultrienews.com.)