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 1 of the latest question and answer installment that you can share with your footcare clients.
Q: With hot summer work, how do I make sure my horses get enough salt?
By Kathleen Crandell, PhD
Equine nutritionists recommend offering supplemental salt (sodium chloride, NaCl) to all horses because typical forages and feeds contain low levels. According to nutritionists, the “salt theory” holds especially true for exercising horses that lose valuable electrolytes in sweat. A recent review of the literature, however, questions traditional views on salt supplementation, suggesting that just a dab will do.
The reviewers indicate that even horses receiving inadequate or no supplemental salt can still maintain good performance and undisturbed health. They hypothesize that horses naturally adapt to low salt levels by decreasing the amount of excretions from their kidneys and hindgut.
To test these assumptions, researchers looked at moderately exercised Warmblood mares on a low-forage diet that were fed increasing levels of daily salt supplementation, as much as 100 grams per day. While the highest level of salt supplementation appeared to have an acidifying effect on blood and increased sodium and chloride excretion in the urine, the moderate level (50g/d) and not offering any supplemental salt did not. Keep in mind this research was done with low to moderate ambient temperatures with no question of heat stress.
However, we believe salt supplementation benefits horses for the following reasons:
1. Equine sweat is rich in sodium and chloride. Diets with limited salt, like most unsupplemented equine diets, may cause disturbances of fluid and mineral balances when a horse is losing electrolytes due to heavy sweating.
2. A horse’s voluntary intake of supplemental salt ranges between 0 and 62 mg salt/kg of body weight daily, which is less than the current recommended intake. Recommendations found in Nutrient Requirements of Horses call for 100 mg/kg of body weight daily for a horse at maintenance levels, which shows a need for salt in many horses.
3. Horses offered plentiful forage can reduce or even eliminate the potential acidifying effect of supplementary salt, thereby negating the concerns about metabolic acidosis that were seen in this study with low forage intakes.
It is not time to throw away the salt block, especially for horses that are exercising for extended periods of time or are being worked in hot environments. If horses are not offered free-choice salt, they frequently seek it from other sources, such as from the soil or treated wood that is used in fencing. Offering free-choice salt seems like a better alternative.
Kathleen Crandell, PhD, is an equine nutritionist with Kentucky Equine Research in Versailles, Ky.
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 2 of the June 1, 2018 installment: Is it OK to feed more than one supplement at a time for improving hoof quality?
Click here to read more installments of Hoof Nutrition Intelligence.