Every living mammal has an endocrine system that includes the thyroid gland located in the neck. Though not a large gland, it’s effect on the body is all encompassing, which makes diagnosing related issues problematic as symptoms are varied and widespread, often mimicking other illnesses.
Here’s the basics. The thyroid gland produces two hormones that are secreted into the blood: thyroxine (T4) and triiodothyronine (T3). These hormones regulate the work done by ALL the cells in the body – think of it as a biological operating system. If too much of the thyroid hormones are secreted, the body’s cells work faster than normal, and you have hyperthyroidism. If you become hyperthyroid because of too much secretion of the hormones from the thyroid gland, the increased activity of your body cells or body organs may lead, for example, to a quickening of your heart rate or increased activity of your intestine so that you have frequent bowel motions or even diarrhea.
However, if too little of the thyroid hormones are produced (known as hypothyroidism – the most common), the cells and organs of your body slow down. If you become hypothyroid, your heart rate, for example, may be slower than normal and your intestines work sluggishly, so you become easily constipated. These are just examples of the most common “symptoms,” but considering the thyroid controls ALL CELLS, specific individuals will have varied and many times very subtle symptoms, which include issues with fertility and pregnancy, skin and hair changes, intolerance to cold and even personality changes.
As it pertains to dogs, and especially breeding, it is important to understand that little is really known about the mode of inheritance. It is rare for canines to suffer from HYPERthyroid, but unfortunately HYPOthyroidism is quite common. Click HERE to review notes from the American Boxer Club’s health seminar with speaker Dr. Peter Graham, AHDL, MSU collated by Jennifer Walker (Newcastle Boxers). Expanded notes are available on her website.
One advocate, Karen Grzenda, is waging a one-woman war against disinformation. She has written several books and administrates a Facebook group (Hypothroidism in Dogs) for dog owners who know or suspect their pet may be afflicted. Per her website, "Normal thyroid function regulates metabolism of all the body's cellular activies, such that reduced function can produce a wide range of clinical signs." A link to a summary of an interview of Dr. Dodds by Karen Grzenda is HERE. Jean Dodds, DVM is a leader in holistic veterinary medicine and opened HemoPet in 1986, after spending more than 50 years as a clinical research veterinarian.
~ Kimberly A.D. Tillman