December 2005

Don’t Dismiss Enlarged Thyroids

With the exception of rare and usually benign thyroid tumors in older horses, or thyroid disorders related to dietary iodine, most veterinarians believe changes in thyroid hormone levels in horses are related to other disorders, not to problems with the thyroid gland itself. Results of a study performed by the Faculty of Veterinary Medicine, University of Bari, Italy, may change that.

The researchers examed 662 equine thyroids and found 156 were abnormal (e.g. goiter/enlargement). Of those, 80% of the thyroid glands had microscopic evidence of changes consistent with Hashimoto thyroiditis in people, an autoimmune disease of the thyroid. In addition, circulating autoantibodies to thyroid hormone and thyroid gland enzymes were found…