Hoof Nutrition Intelligence is a twice-a-month web segment that is designed to add to the education of footcare professionals when it comes to effectively feeding the hoof. The goal of this web-exclusive feature is to zero in on specific areas of hoof nutrition and avoid broad-based articles that simply look at the overall equine feeding situation.
Below you will find Part 2 of the latest question and answer installment that you can share with your footcare clients.
Q: I live in what’s been called an iodine-deficient area of the country. Should this be a concern with my horses?
By Mieke Holder, PhD
Regarded as one of the most critical dietary trace minerals, iodine plays a role in thyroid metabolism and the synthesis of the thyroid hormones triiodothyronine and thyroxine.
These hormones fulfill multiple functions ranging from cell regulation to tissue differentiation and tissue growth. When a horse’s iodine status declines to the point where these hormones become insufficient, an enlarged thyroid gland may result.
Almost all countries have been affected at some point in time by an iodine deficiency. This is due to the fact that iodine concentrations often tend to be low in plants. As a result, iodine deficiencies tend to be more prevalent than toxicity concerns in grazing horses that are not receiving supplements.
Adding iodized salt is an efficient way to increase the iodine content in animal diets, such as with a free-choice iodized salt block. If you happen to live in an area known to be iodine-deficient, local feed manufacturers may already be including iodized salt in their equine concentrates. You can also add iodized salt to your horse’s grain or concentrates. Some owners add a seaweed- or kelp-based supplement to their horse’s diet.
A mature horse weighing 1,100 pounds doing light exercise only requires 3.5 milligrams of iodine per day, based on the National Research Council’s nutrition requirements for horses. The amount should be increased for mares in late gestation, lactating broodmares or horses used in heavy work.
Mieke Holder is a researcher in the department of animal and food sciences at the University of Kentucky.
Hoof Nutrition Intelligence is brought to you by W.F. Young Co. (Absorbine). 
Like many significant achievements, Absorbine® grew out of humble beginnings—and through the tenacity of someone willing to question the status quo. In this case, it was a young woman in late 19th-century Massachusetts: Mary Ida Young. Her husband, Wilbur Fenelon Young, was an enterprising piano deliveryman who relied on the couple’s team of horses to make deliveries throughout the Northeast. Inspired by Mary Ida and Wilbur’s vision, Absorbine® has continued to add innovative products throughout the years — products used every day by horse owners around the world. Which is why, since 1892, we’ve been The Horse World’s Most Trusted Name®.
Click here to read Part 1 of the May 15, 2018 installment: Are there any research studies demonstrating the value of biotin in hoof growth in ponies?
Click here to read more installments of Hoof Nutrition Intelligence.