Feeding Electrolytes to Horses

As a follow-up to our recent post on providing adequate water for horses, the following information should be helpful in understanding the use of supplemental electrolytes for horses.  There are a wide range of practices and opinions within this topic, so here are some basic guidelines to keep in mind:

  1. Provide loose salt free choice at all times to all horses.  If loose salt is provided, horses will usually consume the right amount to meet their electrolyte requirements without having to use an additional supplement. 
  2. Horses administered any form of electrolytes need to be consuming adequate water.
  3. Electrolytes should never be force fed to a dehydrated horse, and any horses supplemented with electrolytes should be monitored for dehydration (skin pinch test, mucous membrane color and hydration, capillary refill).
  4. Electrolytes can be used to encourage drinking (e.g. during transport or if horse doesn’t like to drink away from home).  Usually thirst/drinking is stimulated within 3-4 hours after dosing. 
  5. In cases where horses are working extremely hard and losing electrolytes through substantial sweating, a supplemental electrolyte in addition to the salt may be beneficial. 
    1. If heavy sweating due to competition is anticipated, administer electrolytes 1-2 days prior to competition, during the competition and 1-2 days after a competition. 
    2. Doses are usually within the 1 – 4 oz range, depending on sweat loss and the heat and humidity levels. 
    3. A general rule of thumb is usually 30 – 90 g per hour of strenuous work, or follow manufacturer’s instructions if using a commercial product. 
  6. An oral dose (paste/syringe) is recommended over top dress or adding to water, as these methods can create palatability issues and can result in feed/water refusal.
  7. Many commercial products have more sugar that electrolytes in them, so buying a commercial product where sugar is not listed as one of the main ingredients is very important.  Potassium, sodium, chloride, and calcium are the most important electrolytes.

8 Replies to “Feeding Electrolytes to Horses”

  1. question about providing free choice loose salt…is there a way to buy large packages of salt other than the normal containers you find in the grocery store?

    1. Hi Julie, Great question. Yes, you can buy 40 – 50 lb bags of loose white salt at most feed stores and at TSC. Another option might be purchasing bulk salt from stores like Sam’s Club. Hope that helps!
      Thanks~ Emily L.

  2. Is there a way to supplement electrolytes using salt and or other products in the water troughs? we have 19 horses in our herd and I would like to make sure they are all getting adequate electrolytes in the heat of the summer. I am looking for more info on dosing and amounts of salt to put in the troughs so the horses still will drink the water, but get the benefits of electrolytes. Any info would be great! ~Thanks

    1. Hello Kaitlyn, Thank you for the interesting question. I appreciate your desire to provide a ready source of electrolytes for your horses. The key electrolytes are sodium, chloride, potassium and magnesium. The best way to accomplish this is to provide free choice salt in a loose form at all times as sodium and chloride are the primary electrolytes lost in sweat. Forages and feed normally contain adequate potassium and magnesium to maintain body levels. Horses may not consume enough salt if the salt is in block form, particularly during cold weather or hot, humid conditions.

      If you have particular events where the horses will be worked hard, particularly in hot, humid conditions, it is recommended to provide the additional electrolytes immediately prior to, during and immediately following a competition. Horses cannot store excess electrolytes and will excrete in the urine. Maintaining water consumption is key to preventing dehydration and adding electrolytes to the water may not be desired.

      Dr. Krishona Martinson at the University of Minnesota recently published a useful newsletter review that suggested that adding supplements to the drinking water for horses can actually decrease water consumption, which is exactly what you would want to avoid doing.

      Best wishes, Roy J.

  3. My horse seems to be drinking less than she use to, even though the temperature is going up. My mom thinks that if we add electrolytes to her daily diet that it will solve that problem. Will it? I want to make sure she is getting enough water, but I’m not sure that electrolytes is the right choice. She also always has a salt block.

    1. Hello Shannon, Maintaining water intake is certainly a key area in maintaining a healthy horse.

      Electrolytes can be a very useful management tool and are best used a couple of day before, during and immediately after exercise. Horses cannot store electrolytes, so excess will be excreted in the urine and may increase urine output. A better solution for your horse might be to switch from a salt block to loose salt free choice. A horse requires 2-4 ounces of salt per day, more in high heat, high humidity or with exercise. It is difficult to for a horse to lick that much off of a salt block. Commercial horse feeds also contain some added salt. I would suggest offering the loose salt and keeping an eye on consumption. It is fairly common for horses to consume a higher level for a few days, then level off intake. Fresh clean water should be available at all times.

      You may also want to monitor hydration, particularly during exercise, if you are concerned about water intake. You may want to have your veterinarian demonstrate how to monitor capillary refill time on the gums or “pinch test” on skin.

      Thank you ~ Roy J.

  4. I have a 23 year old mare that still competes in dressage and showing. I am thinking of feeding her an electrolyte supplement but there is a lot of contradictory advice out there.

    Should she be just having it around a competition or is a maintenance dose a good idea? She already has loose salt in her feed.

    1. Hi Caroline, Thanks for the question. It is possible to overdo the electrolytes and cause other problems, so we recommend only feeding a supplement at the time of intense exercise. As a side note, we would recommend providing her loose salt in a separate feeder, rather than directly with her feed, as horses can regulate salt intake on their own. Sometimes adding to the feed can cause them to go off feed if they do not need the salt at the time. Also, if you go with an electrolyte supplement, that will add to her sodium intake, which may impact how much she needs/wants to consume at feeding time. Please let us know if you have further questions!

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