Low thyroid hormone will cause hair loss and skin conditions, obesity, dogs who are lethargic weak, and less active, and dogs who like to seek out heat. That means they will lay out in the sun even on a hot day or continually seek out the hot spots by the fire or furnace. All of these problems tell us that the thyroid gland is important for our health. We tested the dog for its thyroid level using a fairly inexpensive test and found that indeed this thyroid had stopped functioning. This provides a simple and inexpensive solution to a dogs obesity, lethargy, and skin conditions.
Cats are a different story.
They most often have a thyroid problem where the thyroid gland over produces hormones. This increase level of thyroid hormone causes weight loss in the face of an increasing appetite. These cats are restless and hyper-excited. They often have poor hair coats, vomiting, diarrhea, and panting or weakness. Inside, the most common problem caused by high thyroid hormone is heart disease.