A dehydrated horse can be a major concern of horse owners during all months of the year. Dehydration occurs when a horse loses a substantial amount of water from the body without replenishing it.
Causes of dehydration in horses range from high intensity work to a long trailer ride with poor ventilation, or any other factor that could make your horse sweat or lose excess water through urine or feces. Additionally, dehydration may occur in exceptionally cold weather, when water troughs freeze over and/or horses drink less due to cold water temperatures.
So, how do you know when your horse is dehydrated?
There are two easy methods to measure your horse’s hydration status (without having to draw and analyze their blood):
- Capillary Refill Test. To perform this test you will assess the color of your horse’s gums. The proper gum color for a horse is a bright bubblegum pink, and the gums should be moist. With one finger, press on your horse’s gum, which will temporarily turn white. When you release your finger, count how many seconds it takes for the gum color to return to the normal pink. If this amount of time is around 1-2 seconds, then your horse is properly hydrated. If it takes longer than this, or you notice that your horse’s gums are dry or tacky, your horse may be dehydrated. This is called Capillary Refill Time because it measures the amount of time it takes for the blood that you pushed out of the capillaries with your fingers to return.
If the idea of sticking your fingers into your horse’s mouth doesn’t thrill you, there is an alternative method:
- Skin Pinch Test. To perform this test you will pinch a section of your horse’s skin on their shoulder or neck and pull it away from their body to make a little tent. When you release, then skin should return to its normal position on the body in 1-2 seconds. If it is slow to return, the normal elasticity of the skin has been lost and you likely have a dehydrated horse.
How do you treat a dehydrated horse?
If you find that your horse is dehydrated, you will want to provide plenty of cool fresh water and allow them to drink freely. However, in cases of extreme dehydration in horses, you may need a vet to run a nasogastric tube to administer fluids directly to the stomach, or to provide IV fluids. Call your vet if you are unsure of how to proceed. It is always better to be safe than sorry.
Can dehydration cause colic in horses?
Dehydration can lead to a complication that might not be the first thing to come to mind... colic. With dehydration, the amount of fluid proper for necessary digestion will not be present in the horse digestive tract. Most commonly, this will lead to impaction colic, because feed particles will not flow properly and may dry up in the digestive tract causing feed to get stuck in the gut (1). If your horse experiences an impaction colic, you will likely need your vet to provide IV fluids to rehydrate them. Horses absorb water in the large intestine, at the very end of the digestive tract, and if an impaction colic occurs, water that is consumed by the horse orally will not be able to reach the site of absorption, worsening both the colic and dehydration.
How do you rehydrate a horse?
Obviously dehydration in horses is no fun and may leave you with a hefty price tag, so prevention is key. Always make sure that your horse has access to clean, fresh water they can drink. This water should be like Goldilocks would like it- not too cold, not too hot, but just right, as cool water is optimal to maximize intake.
Another way to ensure your horse is well hydrated is to provide your horse with an electrolyte supplement before, during, and after intense exercise. While providing electrolytes after a large loss of fluids may be helpful to rehydrate, it is far more beneficial to provide electrolytes to ensure proper hydration before exercise in order to prevent dehydration. Think: be proactive rather than reactive.
Did you know that horses have a different sweat composition than humans?
When humans sweat, the fluids lost are considered hypotonic, meaning that the concentration of electrolytes in the bloodstream are higher than what is lost in sweat. In contrast, horses have hypertonic sweat, which means that they lose higher concentrations of electrolytes in their sweat than what remains in their circulation.
So, what does this mean?
Electrolyte supplements that are formulated for use by humans are generally not sufficient for horses, due to these physiological differences. Rather than using Gatorade powder or something similar in their water, it is worth your while to provide horses with an electrolyte that is formulated specially for our equine partners. These electrolytes can be found as powders or pastes and come in several flavors, giving you plenty of opportunity to find the right fit for your four-legged partner.
Take Home Messages:
- Dehydration can occur throughout the year and for various reasons.
- You can use the Capillary Refill Time or Skin Pinch Test for dehydration to assess your horse’s fluid levels.
- Depending on severity, dehydration may be cured by offering access to free drinking water.
- In severe cases, dehydration may cause colic, which must be treated with IV fluids.
- Prevention is key: provide your horse with plenty of access to free water and electrolytes before, during, and after potential loss of fluids. Use electrolyte supplements formulated specifically for horses.