Weather changes in the fall and winter can affect a horse’s water intake.
Most dehydration colic cases occur in the summer and winter, and especially when temperatures change quickly.
Horses can get behind on water intake when temperatures rise quickly, and they are likely to drink 6-14 percent less water during a cold snap.
Veterinarian Dr. Erik Moore discussed how different factors play into a horse’s hydration status, what can be done to prevent dehydration, and how to properly use electrolytes.
Horses will take one long drink with many sips several times each day. On average, a horse at maintenance will drink two to eight times per day for 10 to 60 seconds, for a total of six to ten gallons consumed each day.
Water intake levels can change with a variety of factors, including when horses are participating in heavy exercise, when temperatures rise, when humidity is high, and what type of feed a horse is consuming.
“Under heavy exercise and really hot weather, some horses can need up to 30 gallons a day, so about six large buckets,” Moore said.
A horse that is being hauled, and therefore eating grain and hay, will need to consume more water than one that is turned out on pasture.
Pasture contains 70-80 percent water while dry feed and hay contain only about 10-15 percent water.
Moore said supplementing one ounce of table salt on top of grain twice each day is a simple, easy, and safe way to encourage a horse to drink more water.
Offering a free-choice salt block, both at home and when traveling, is also an excellent way to allow horses to self-regulate their electrolyte and water consumption.
Horses lose water primarily through urine, feces, sweat, and respiration. Dehydration is scientifically defined as an 8-10 percent deficit in water throughout a horse’s body.
Knowing the signs of dehydration begins with knowing what is normal for your horse.
This includes doing simple hydration tests when you know a horse is well hydrated, paying close attention to the horse’s physical appearance, and taking note of things like a horse’s feed consumption and urine color.
A quick way to tell if a horse is beginning to be dehydrated is with a skin test. Lift your horse’s skin by gently pinching a small piece, usually on their neck. The skin should snap back into place withing one to two seconds. If it takes longer than two seconds, this is a sign the horse is dehydrated.
Another way to check a horse’s hydration status is through the capillary refill time in their gums. Press your thumb against your horse’s top gum and then release. The color should come back to the area within one to two seconds.
Another simple way to look for dehydration is by noticing the soft area just above a horse’s eye.
“There’s a little soft spot you can feel. As a horse gets dehydrated, they will sink in there a little bit. A lot of older horses look that way anyway, but if you are familiar with your horse and you notice he’s sunken in more than normal, especially if you are paying attention, that’s a really easy one to see just visually,” Moore said.
Regular urine is a light color, almost close to clear. The darker or more yellow urine is, the more dehydrated the horse.
Electrolytes are essentially specific minerals that help a horse stay hydrated. These minerals include table salt, potassium, calcium, and magnesium.
When temperatures rise, humidity rises, and exercise levels are high, it might be a good idea to supplement some electrolytes.
When hauling, Moore said offering constant water to a horse in the trailer is great if the water is fresh and the horse is willing to drink it. Otherwise, it is best to offer the horse good, clean water at least every six hours while traveling.
If an owner wants to use electrolytes as a preventative from dehydration when traveling, Moore said it is a good idea to make electrolytes part of a routine when traveling, rather than a one-time-use.
The most appealing water to horses will be fresh, clean, and cool. About half a bucket or approximately 10 quarts at a time about every 45 minutes is best until the horse becomes rehydrated.
Mild dehydration can be treated at home with clean water and an electrolyte supplement. Extreme cases of dehydration, where a horse loses access to water for hours at a time, can be treated with intravenous IV fluids.
“The biggest conversation I have about hydration is usually on a horse associated with a colic episode. So, I would say it is very common for us to assess the horse’s systemic hydration status and then use IV fluids,” Moore said.
