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: Can excess dietary salt affect hoof quality?
By J. Frank Gravlee, DVM, MS, CNS, and Scott Gravlee, DVM, CNS, Life Data Labs
A: Salt, or sodium chloride, is a necessary component of a horse’s diet and is required for effective metabolism. However, too much salt will increase thirst and urination.
Hoof quality can deteriorate from the additional urine and moisture in the environment. The hooves of horses that are confined for periods of time are primarily affected.
The excess moisture softens the hoof wall and sole leading to weakening of the hoof, wall separations and cracks. The sole swells, the white line widens and the softer hoof wall bends outward. This has the adverse effect of shifting and increasing weight bearing on the sole rather than the hoof wall.
Hoof-eating microbes also have increased opportunity for invasion. These softened structures are more likely to be ground and abraded away from exercise or stall boredom.
To add further insult, urine-soaked bedding has been associated with higher ammonia levels. Ammonia is not only damaging to the horse’s respiratory system but is very destructive to the hooves. Urine contains a breakdown product of protein metabolism called urea, which is converted to ammonia by the microbial activity found in bedding.
Although salt intake would not affect the horse’s total daily urea output, the additional moisture from increased urine output facilitates the bacterial production of the enzyme that breaks down urea into ammonia (urease). A horse’s salt requirement varies depending on several factors, including activity level and the amount of sweating. The maintenance requirement of a 1,100-pound horse at rest is approximately 25 grams per day. On the other hand, a horse in heavy work may require up to 200 grams of salt per day. Fortunately, by offering free-choice salt, the vast majority of horses voluntarily consume only the amount of salt that they require.
Unlike the rough tongue of a cow, the smooth tongue of the horse is inefficient at licking salt from blocks designed to withstand the weather. Free-choice loose white livestock salt is the best option.
Compounded feeds usually contain added salt at 0.5% to 1.0 % levels, which . increases the palatability of the ration. Hard keepers that need large feeding levels of a compounded feed in order to maintain their weight can consume significant levels of salt.
For example over the course of a day, a hard-keeper horse fed 12 pounds of compounded feed with 1% added salt would be consuming 55 grams of salt. As a result, a horse that is not working or sweating is being force-fed more than twice the daily requirement. A better option for hard keepers would be feeding a low-salt ration such as a forage balancer and a non-fortified calorie source such as whole oats. Add free-choice loose white salt and fresh water for a balanced diet.
As a closing thought, could excess salt intake with subsequent fluid retention in the highly vascular areas of the sensitive laminae create a harmful effect on horses with chronic laminitis?
J. Frank Gravlee, DVM, MS, CNS and Scott Gravlee, DVM, CNS are veterinarians and equine nutritionists at Life Data Labs, Inc. The firm is a dedicated product manufacturer committed to supplying premium quality animal nutrition and health products.
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 April 1, 2015 installment: Are fever and stress rings in the hoof due to nutritional changes?
Click here to read more installments of Hoof Nutrition Intelligence.