Epson Salt also known as Magnesium Sulfate, 

Magnesium plays an important part in nerve and muscle function, and horses deficient in this important element can show signs of nervousness, wariness, excitability, and muscle tremors.
This gives magnesium its reputation for having a calming influence on equines.
A deficient horse is likely to have a poor tolerance to work and its muscles will tie up quite quickly.
Magnesium is also known to play an important part in reducing equine obesity, and can lessen the risk of laminitis in animals prone to it during periods of strong spring grass growth.

Epsom salts is best known as a laxative.
Give your horse an overly generous amount and, just like people, they’ll be feeling the effects of diarrhoea.
Anything greater than one level tablespoon a day per 100kg of your horse’s bodyweight is likely to result in a case of this.

The magnesium requirement of a typical horse was put at 13 milligrams per kilogram of bodyweight per day.
Horses that are growing, lactating, or in work will use more each day.
For example, a lot of magnesium can be lost in sweat.
For such animals, the quantity could be increased 1.5 to 2 times the maintenance dose.


Supplementation of magnesium in a deficient horse will have a huge effect on its wellbeing.