A properly functioning thyroid gland is highly important to a horse’s good health. That much is easy. From there it gets more difficult and complex. Knowing when the thyroid gland is in a state of dysfunction is not easy to determine.

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NAN RAWLINS PHOTO

If the thyroid gland is removed, animals show several signs, including a dull, coarse hair coat that fails to shed at the appropriate time.

The problem or issue before the house, at least one researcher believes, is that the thyroid gland, in a number of instances, might be innocent of any wrongdoing and that some treatment protocols are creating problems they are seeking to remedy. That researcher is Nathaniel T. Messer IV, DVM, of the University of Missouri in Columbia. At the December, 1998, AAEP meeting in Baltimore, Messer, who conducted a good deal of research on the thyroid gland, also presented a paper that detailed the results of a study at two central Kentucky Thoroughbred farms involving low hormone levels in mares and foals.

Messer summarized the complexity of the thyroid debate with this opening statement in his presentation at Baltimore:

"There is a wide spectrum of equine clinicians with varying beli