Hot summer days. Your horse has a salt block and a stock tank of water. Is that enough?
◆︎ Causes of dehydration:
Sweating: Horses sweat to cool. On a hot summer day, you may see just a glimmer of sweat over their entire body. You may think that they are not sweating a lot. However, the sweat is evaporating, which causes cooling. It’s easy to be lulled into thinking that they aren’t losing much body water.
In moderate weather, horses can lose up to 2 gallons of sweat per hour. Light foam between the back legs could may indicate about 3 gallons of sweat per hour.
With excessive heat or exercise, the amount of sweat can approach 4 gallons of sweat per hour.
Lack of sufficient water intake:
This could be due to a number of factors.
➡ The water in the tank is too hot.
➡ The water isn’t clean enough.
➡ The excessive loss of electrolytes due to sweating may cause the thirst mechanism to be downregulated.
◆︎ Regulators of thirst mechanism
Sodium concentration within the body triggers thirst. If the horse sweats and the sodium levels increase in the body, the horse’s thirst mechanism is triggered to drink.
However, when there is prolonged dehydration and a significant loss of sodium, the thirst mechanism may not trigger.
This means that increased salt intake will signal the horse to increase water consumption.
◆︎ Risks associated with dehydration
Dehydration can be a serious matter in the horse. The horses may suffer from
» Colic
» Heat stroke
» Lethargy
» Tying-up
» Loss of focus
Dehydration can even be life threatening.
◆︎ Why do horses need additional salt added to their diet?
Most hays and grasses in North America are low in sodium. Because our horses are not free-ranged, they don’t have the ability to find salt pans or soils with higher sodium levels. Wild horses find salt pans and soils with higher salt concentrations, as well as a diversity of plants. Our horses, kept in pastures and stalls, don’t have that opportunity.
◆︎ My horse has a salt block, but barely touches it.
There could be a variety of reasons why a horse doesn’t consume sufficient salt from a salt block.
➡ The horse could be very dehydrated and the drive for salt has been downregulated as a result.
➡ The salt block could be dirty.
➡ The salt block could taste funny.
➡ Wild animals, like squirrels or rats may have urinated on the salt block.
➡ The horse could have mouth ulcers, which makes it painful to consume the straight salt.
➡ The horse could be in the process of shedding teeth and have sore gums.
➡ The horse could have had a bad experience in the past due to mouth ulcers or shedding teeth and shy away from the salt block, even though that previous mouth pain no longer exists.
It’s important to rinse off your salt block regularly.
◆︎ Is salt enough?
Salt is made up of sodium and chloride. As mentioned above, the sodium levels are what triggers thirst.
However, the main components of sweat also include sodium, potassium, chloride, calcium, and magnesium.
◆︎ Electrolyte caution
Always check the ingredients in the electrolytes that you purchase. Many of the electrolytes will have added dextrose. This is so that the electrolytes are tastier, as well as supplying energy to the muscles. However, for insulin resistant horses, dextrose can also spike insulin levels. Dextrose is made up of glucose.
◆︎ IR Safe electrolytes
My Best Horse’s Equine Electrolytes are safe for insulin resistant horses. There is no added sugar nor flavorings.
◆︎ How to give your horse electrolytes
▪ Electrolytes can be added to a bucket of water. Be sure that plain water is also available to drink.
▪ Electrolytes as a paste may cause water to be drawn into the horse’s stomach and intestines. This may cause a temporary worsening of the dehydration. Additionally, the paste may cause gastric irritation.
▪ Electrolytes can be added to a feed bucket.
▪ Electrolytes can also be sprinkled on moistened hay.
◆︎ When dehydration is severe
Call a vet. He/she can medically treat a horse with severe dehydration. This could include administering intravenous fluids, as well as other treatments that your vet deems appropriate.
We do the best that we can do for our horses. In this excessive heat wave, monitoring your horse for dehydration is a part of that.
Disclaimer: Statements regarding dietary supplements have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease or health condition.
©Joan Kulifay 2025