Iodine Deficiency in Goats
One Reason for Late-Term Abortions
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Iodine deficiency in goats. Did you ever hear about the “goiter belt” in health class? It was a wide swath of land through the northern United States in which a high percentage of people had goiters up until 1924 when iodized table salt became standard. Well, goiters don’t only happen in humans; they can happen in animals, too. Goats are especially susceptible to goiters and iodine deficiency.
Iodine Deficiency Symptoms in Goats
A goiter in a goat presents as a swollen lump on their neck, just a little below their jaw. This is not to be confused with bottle jaw, which is swelling right under the jaw. While developing a goiter or enlarged thyroid gland is the most common symptom of iodine deficiency in goats, it is often not the first symptom if your goats are due to give birth soon. A pregnant doe that is suffering from iodine deficiency will often have a late-term abortion. If she is able to keep the kids until full-term, they likely will be stillborn. An iodine-deficient baby goat is often hairless and will have a visibly enlarged thyroid gland. The doe may experience a retained placenta or pregnancy toxemia (Hart, 2008).
Babies born alive have a small chance of living, depending on how bad their deficiency may be. If you work quickly, there is a chance that you could reverse the deficiency and save the kid. Gloria Montero has been able to do this. When her herd was suffering from iodine deficiency, she had a goat give birth to triplets. One was stillborn, and another was born barely alive but died shortly after birth. They were both hairless and had goiters. One of the triplets was born with normal hair but still had a very enlarged thyroid gland. But did she know how to fix iodine deficiency in goats? Gloria swabbed liquid iodine under his tail multiple times in the first few days of the goat’s life, and he managed to pull through to become a healthy goat.
Primary vs. Secondary Deficiency Iodine Deficiency in Goats
Gloria had to consult her vet about the obvious iodine deficiency present in her goat herd. She gave free-choice minerals, and they contained sufficient iodine. However, her vet, Dr. Forbes, helped her become aware of another way in which goats can be deficient in iodine. This is termed secondary deficiency.
Primary deficiency would be when there is insufficient iodine in the diet. Secondary deficiency is when something is preventing the absorption or utilization of iodine in the body. That something preventing the goats from absorbing the iodine in their diet was a food. “Goiter, or an abnormal enlargement of the thyroid gland, can be hereditary or caused by such things as iodine deficiency or the consumption of goitrogenic compounds,” said Nevada Department of Agriculture (NDA) veterinary diagnostician Dr. Keith Forbes, DVM. “Goitrogens are substances that block the activation of thyroid hormones by iodine and can be present in cabbage, broccoli, sorghum, and other food items. Decreased iodine levels can also result from consuming what may appear to be a proper diet. Iodine can be leached out of feedstuffs grown on poor (sandy) soils or the absorption of iodine in the intestines can be decreased by consuming excess calcium or nitrates.”
While Gloria was never under the impression that goats can eat literally anything, she had no idea that certain foods that goats like could cause a vitamin deficiency. These foods are mostly the Brassica family. This includes broccoli, cabbage, Brussel sprouts, and mustard greens. Other foods that also contribute are soy, peanuts (including the plant tops), and oil meals such as rapeseed meal. They contain a substance called glucosinolates (Department of Animal Science — Plants Poisonous to Livestock, 2019). When eaten, these glucosinolates block the thyroid from using the iodine that is in the body. This causes symptoms of underactive thyroid and iodine deficiency even though the goat is eating enough iodine. This effect is so strong that studies have shown that a goat would need 2.5 times the adequate intake of iodine in order to not be deficient (Bhardwaj, 2018). This would have to come in the form of specific iodine supplementation, not just free-choice minerals.
Many areas of the United States (and the rest of the world) have sufficient iodine in the soil that plants intake, thereby passing it on when humans or animals eat the plant. However, there are certain areas, often places that are mountainous, that lack sufficient iodine in the soil. That is why the United States had a “goiter belt” from the Rocky Mountains through the Great Lakes Region, and even into upstate New York. Other mountainous regions in the world are often prone to being iodine deficient. The fortification of certain foods, iodized salt, and the ability to transport food from different areas has all lessened the prevalence of iodine deficiency with the appearance of goiters.
This doesn’t mean that your goats can never have broccoli or mustard greens. It just means that you will have to use moderation. It has been shown that for goats, they can have no more than 10% of their feed come from rapeseed meal (canola) as long as there are no other Brassicas in their diet. Goats can have those cabbage leaves or the stalk of your Brussels sprouts, but they can’t have a lot of it or all the time. Remember to balance your goat’s diet.
There are many ways in which a goat can become deficient in a vital nutrient. The best way to prevent nutrient or vitamin deficiencies is to know the mineral content of your soil. Your local extension or county office will have information on what minerals are prevalent or deficient in your soil. Utilize them and their knowledge.
Bhardwaj, R. K. (2018). Iodine Deficiency in Goat. In Goat Science (pp. 75-82). London, UK: IntechOpen.
Department of Animal Science – Plants Poisonous to Livestock. (2019, 2 28). Retrieved April 24, 2020, from Cornell College of Agriculture and Life Sciences: https://poisonousplants.ansci.cornell.edu/toxicagents/glucosin.html
Hart, S. (2008). Meat Goat Nutrition. In Proc. 23rd Ann. Goat Field Day (pp. 58-83). Langston, OK: Langston University.
Originally published in the November/December 2020 issue of Goat Journal and regularly vetted for accuracy.