In the heat of summer, a horse's water requirement can double or even triple, since he uses water to help cool his body. Water makes up about 70% of body tissues. It is the major component of all cells and is required for all of the chemical reactions that occur as part of normal digestion and metabolism.

A  3% loss of body water can result in performance decreases in horses. For example, a 1000 lb horse contains about 700 lbs of water, and 3% of that would be about 21 lbs. Half of a five gallon pail of water would weight about 21 lbs. The point here is that you would not be able to look at your horse and notice a 21 pound difference, so he could easily be dehydrated without your knowledge. And, even worse, at 16 or 17% dehydration, your horse's life is in danger.

So, what regulates thirst, drinking behavior, urine production and water retention in horses? That's right, minerals, specifically salts or electrolytes. Sodium is the main electrolyte in the blood and other extra cellular fluids. Potassium is the main electrolyte within the cells. Calcium, magnesium and chlorine are also important electrolytes.

These minerals, except potassium and sometimes calcium, are lacking in typical horse feeds and must be supplemented. If horses don't regularly get enough salts, they can be continuously dehydrated, and will not be able to perform at maximum capacity.

Luckily, horses are able to excrete excess salts, within reason, so overeating of salt is not generally a problem. One exception is that horses with the genetic predisposition to Hyperkalemic Periodic Paralysis (HYPP) do not tolerate excess potassium and require low potassium rations (see HYPP Technical Bulletin).

In conclusion, it is very important, especially in the summer, to make sure your horse doesn't get dehydrated. Horses must eat enough salts to remain in proper water balance for optimum performance and health.

For More Information e-mail at AN_EquineHelp@admworld.com

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