Dehydration in horses can be an overlooked (and dangerous) problem, especially if owners do not know what to look for. Water is not only a requirement for all living things, but it plays a vital role in horses’ digestive systems, performance, and thermoregulation. Water also maintains moisture levels in feces, normal blood volume, and keeps sweat gland functioning regularly. Here’s what you need to know about dehydration in horses:
Water Consumption Requirements
Water intake requirements vary based on work load, weather conditions, and other physiological factors. However, on average, a 1,000-pound horse will take in a minimum of around 10 gallons of water per day. This is roughly 1 gallon of water per 100-pounds of body weight, at the very least. 60% of a horse is water- like other living things, these fluids must remain replenished and balanced. During hot weather, if eating specific diets or supplements, or with intensified work, horses may need to consume more water. In fact, working in hot climates for extended periods of time can quadruple a horse’s required minimum intake. Dehydration in horses is a serious matter, and can be fatal. After only a few days without water, organs will begin to shut down and cause irreversible damage.
Dehydration Symptoms
Although dehydration can vary in degree of severity, there are multiple signs you can watch for if you notice decreased water consumption or have suspicions. A change in vital signs can be seen when a horse is only 4-6% dehydrated, whereas visual signs may not appear until dehydration reaches 8-10%.
Gum Color
This can be a two-fold sign. Horse owners can press on the gums by the horse’s upper front teeth until the skin lightens. When pressure is released, the capillaries should refill quickly and color will return to normal. When the refill color takes more than two seconds, this can be an indicator of dehydration. Gums can also be excessively red due to fluid movement to compensate for dehydration.
Heart Rate
A safe resting heart rate for a horse is between 32-42 beats per minute. Higher resting heart rates (above 60 beats per minute) can indicate a multitude of issues, but may also apply to dehydration.
The Skin Test
This is not a proven stand-alone method, but is a helpful tool. The “skin pinch” test can be performed near the horse’s chest or base of the neck. When pinched for 2-3 seconds, the skin should return to normal immediately. Otherwise, lack of elasticity may indicate dehydration.
Respiration Rate
Average breathing rates fall between 8-12 breaths a minute. Dehydrated horses will have a more rapid and shallow breath pattern.
Impaction Colic
Although it may seem like colic is a symptom (or byproduct) or most ailments or issues, lack of moisture can affect the digestive system and fecal matter.
Dark or Lack of Urine
Dark discolored urine, or a horse failing to produce urine, can indicate inefficient hydration.
Bloodwork
A blood sample is the best way to diagnose and measure dehydration. Your veterinarian can measure the proteins in the plasma and red blood cell comparisons.
Causes of Dehydration in Horses
The sweat produced by horses is hypertonic, meaning it contains more salts than fluid. This results in a higher loss of electrolytes. Although it would seem horses are more prone to dehydration during summer months or high heat conditions, dehydration can occur at any time. In fact, many owners see a rapid drop in water consumption during cooler weather. Horses will become accustom to a certain level of water intake due to the heat- when temperatures drop rapidly, they are not as thirsty. Water intake can drastically drop during cool weather, resulting in unexpected winter dehydration.
Underlying health conditions may also result in hydration issues. Lactating mares require upwards of 20 gallons of water per day in order to adequately replace what was lost in their milk.
Treatment
The first step in treating dehydration is to ensure the horse has access to a clean and fresh water supply. It is important to monitor the horse and the quantity of water consumed. Heating the water (and monitoring temperature) can encourage horses to drink in cold weather. Horses also have salt requirements, with an average 1,000- pound horse needing around 2 ounces per day. By increasing salt intake, horses will be encouraged to drink more. Quality feeds and possibly electrolyte supplements for problematic horses can help prevent any electrolyte imbalances from occurring.
The hypertonic sweat mentioned above is one the key reasons re-hydration is best achieved with electrolyte formulas rather than water alone. Water alone will take care of any “thirst” due its dilution of other bodily fluids, but horses may require more than readily available water to rehydrate properly. In more severe cases, your veterinarian can administer IV fluids and specialty electrolyte solutions. This should only be done by your vet, as excess fluids can also cause damage.
Prevention
The best dehydration prevention is full access to fresh and clean water at all times, including at shows or events. Hydration can be an issue during travel, but easily remedied. Trailer tanks allow water sources from your stable to be transported with your horse. Utilizing flavored electrolytes can also encourage horses to drink if they are picky about water taste away from home. Access to deep shade will also help horses in summer heat.
Horses should also have access to salt daily, and it encourages horses to drink water. Studies have shown horses strongly prefer lukewarm water, as horses tend to drink significantly less water when close to freezing. Water heaters or insulated buckets can greatly increase a horse’s water intake during the cold months. If you have a horse prone to dehydration, daily electrolyte supplements can be used. We recommend consulting your vet first, as always.
Closing Thoughts
Dehydration is a dangerous and possibly lethal problem in horses and livestock. It is important to be aware of possible causes as well as clinical symptoms. Like other animals, monitoring water intake is important for their overall health and the possible indication of dehydration.
Fall is near, which means major changes in weather ahead. Be sure to share this article with your fellow horse owners!