Understanding and meeting your horse’s electrolyte needs.

You know your horse needs salt. But what kinds of salts, and how much does he really need to maintain and promote his health and well-being? More and more people are providing their horses with exotic salts, and are sometimes giving them too much.

Salts are important nutrients. But when any nutrient is given to horses in excess, it can be toxic. For example, most of us know that dietary starch is needed to provide energy, but that too much can cause laminitis. The same is true with salts. Horses need dietary salts for many beneficial reasons. But it is also easy to give them too much of one or more of the nutrients found in the various salt mixtures you can buy at the tack store.

What is salt?

It is important to understand how salts exist within the horse’s body. A salt is formed when a negatively charged element (anion) bonds with a positively charged element (cation); this happens when the solute (e.g., water) is unable to keep the salt dissolved. For example, table salt is sodium chloride. The sodium carries a positive charge (Na+) and the chloride a negative charge (Cl -). When in solution, such as water or body fluids, the elements within salts exist as individual ions, or electrolytes. The other main electrolytes found in body fluids are potassium (K+), calcium (Ca++) and magnesium (Mg++). There are many others, but these are present in much lower concentrations in the body.

Understanding Electrolytes

Electrolytes, which come from the salts we eat, play important roles because they make every cell and organ in your horse’s body work. Their main functions include the transmission of electrical signals from the brain to the spinal cord, and the transmission of signals from the spinal cord to the muscles.

Electrolytes are needed to make the muscles contract and relax when the horse moves and breathes, and for the normal function of every cell in the body. They are also what help keep water within the body; they maintain the correct balance of water inside and outside the cells. The cells also recognize each of the different electrolytes found in the body fluids surrounding them; they do not function properly when any one of these is too much out of balance. Too much or too little of any one electrolyte will result in clinical signs. Balance is key.

Finding a Balance

So what is the right balance of salts for your horse? The NRC’s 2007 Nutrient Requirements of Horses states that it depends on what your horse does on a regular basis. If you have a leisure horse that receives infrequent amounts of light exercise, then the electrolytes and minerals consumed in forage, concentrates and ration balancer will provide everything he needs in close to the right balance.

Forage is relatively high in chloride (50 to 70 grams/day) and potassium (60 to 90 grams/day) but low in sodium (1 to 3 grams/day). While grain is a poor dietary source of electrolytes, sodium (15 to 20 grams/day) and other minerals are added to concentrates to meet dietary needs.

When there is a little too much of one or more electrolytes, the excess will easily be eliminated by the kidneys in the urine, thus maintaining balance within the horse. If there aren’t enough electrolytes, and this continues for a long time, the horse will become deficient, and may eventually show clinical signs.

In contrast, horses in heavy and regular exercise training, and/or running at moderate to high speeds, sweat a lot. The evaporation of this sweat has a cooling effect. But sweat is very rich in electrolytes, and heavy sweating for more than an hour causes dehydration and electrolyte loss.

Big losses of electrolytes cannot be quickly replaced by eating forage, grain rations, and ration balancers; several days are required to replace the losses caused by prolonged periods of sweating. Also, giving a dehydrated horse dry feed is dangerous. A dehydrated horse must be given adequate water, with the right balance of dissolved salts, to rapidly restore the proper balance of water and electrolytes in the body. The right balance will be an electrolyte mixture that mimics the composition of electrolytes lost in sweat. One should not use a “natural” salt mixture to replace electrolytes lost by heavy sweating, because its composition is very different from that of horse sweat and will not provide salts in the proper balance.

The Body Knows What It Needs

We also provide salt blocks for the 30 to 40 horses on our farm, both blue and red, even though according to our nutrition balance program they do not need it. We know each horse is consuming adequate salt from the forage, grain ration, and ration balancer he receives. The horse’s body also has a way of sensing what he needs or is deficient in, and he will lick the salt block if he needs to. We also provide the blocks for some of the trace minerals that may not be adequately supplied by a ration balancer.

In closing, balance is crucial. Consider your horse’s needs (not yours!) by considering the quality and quantity of his diet, how much and what kind of exercise he receives, and how the time of year impacts electrolyte loss due to sweating. If you are still not sure what your horse needs, or would like confirmation, knowledgeable veterinarians and equine specialists will be happy to help you out!

Exotic Salts

I don’t know why people feed their horses exotic salts, because their composition is very different from what is found in the equine body. Sea salt is for seahorses. It’s rich in a variety of electrolytes and trace minerals – but it also contains contaminants arising from nearly 200 years of industrial pollution.

The internet provides many examples of the benefits of “natural” sea salt, Himalayan salt, and ancient sea salt from mined deposits. These all contain many other elements than necessary dietary salts do, and when dissolved in body fluids, may not be in the right balance for your horse. Some are toxic when too much is consumed.

In addition to getting electrolytes and other minerals from dietary salts, your horse also gets them from forage and various grain rations and ration balancers.

Dr. Mike Lindinger has been studying hydration and electrolyte balance in horses for 20 years. He has published numerous scientific articles and book chapters on t equine physiology and nutrition. He is presently co-owner /operator of the Nutraceutical Alliance and Lindenfarne Horse Park.