Chlorine

When someone mentions chlorine (Cl) to you, probably the last thing you think of is your horse's diet.

If you're lucky, you think of a beautiful swimming pool, and all the fun you could have swimming on a hot summer afternoon.

Or if you're not so lucky, maybe you think of bleach, and all the housework and laundry you use it for.

However, Cl is also a very important part of your horse's diet.

So, what does it do in your horse's body?

It works as the major anion (negatively charged molecule) in your horse's body. In the anion form it is called chloride.

It is found in the extracellular fluid, or fluid outside cells. Here it helps regulate the acid-base balance as well as the osmotic pressure.

It also has a couple of other important jobs though as well...

It is an essential component of bile, which is made by the liver and secreted into the large intestine to help with digestion of fat.

It is also important to help form hydrochloric acid, another important secretion for digestion.

So how does your horse obtain this important macromineral in his diet?

Chlorine pool water.

Chlorine Sources

Almost all of your horse's dietary intake is going to come from common salt. Remember the chemical abbreviation of salt??

It's NaCl. Most people know that the Na is for sodium, but many do not remember that the Cl is for chlorine...or chloride. Sodium chloride is common salt, and it is 61% chloride.

Other feedstuffs do contain Cl as well, as listed below:

  • Grass Hay - 0.92%
  • Legume Hay - 0.61%
  • Grass Pasture - 0.58%
  • Beet Pulp - 0.17%
  • Corn - 0.05%

This is not a complete list, but its a list of some of the more common ones, to give you an idea of the amount of Cl found in feeds.

Chlorine Toxicity

Cl toxicity is of little worry for horses due to their ability to process large amounts of salt, and therefore large amounts of Cl.

The only time a horse may have problems with a toxicity would be if ample fresh water was not available.

Though a Cl toxicity has never been reported in horses, it is assumed that they would behave like other species in the presence of a salt toxicity and have problems with their central nervous system.

Chlorine Deficiency

Since common salt is 61% chloride, your horse isn't likely to have a Cl deficiency.

However, if a horse derives his sodium from sodium bicarbonate (baking soda), it is possible to get a Cl deficiency since he will not be consuming as much salt.

Signs of deficiency include decreased feed intake, muscle weakness, decreased milk production in the lactating mare, possible weight loss, and dehydration.


The equine diet is not something we generally think of first when Cl is mentioned, but it is a vital part of your horse's healthy diet.

Thankfully it is very easy to meet requirements due to the intake of common salt and toxicity and deficiency are of very little concern.


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