How can I tell if my horse is becoming dehydrated?

This is a great question, and just in time for summer when it’s hot!  Or winter, when horses don’t like to drink as much.  
As with all things horses and grooming - knowing how your horse is normally will alert you to times when things are “just not right”.  This definitely applies to his state of hydration.  

Just as we can gauge a horse’s normal TPR (temp, pulse, and respiration), there are a few ways in which we can gauge his hydration.  Here we go:



Water should be clean and not frozen!  


  • Skin tent test.  For this, you simply pinch a bit of his skin on his neck or shoulder area and see how long it takes for his skin to snap back to normal.  A dehydrated horse will typically take longer to snap back, and his skin will look like a tent in the meantime.  This test is somewhat unreliable, as skin loses elasticity over time, but it’s still a way that you can measure how hydrated your horse is.  Pair this test with a gum inspection for best results. 


  • Gums.  They should feel slimy.  Sticky or dry gums are dangerous, as are gums that are red or blue.  This is a great reason to be able to inspect your horse’s mouth and gums.  Practice every day and it gets easy.  It takes a millisecond!


  • Capillary refill time.  Now that you can feel gums and check gum color, put your thumb on the gum and press.  When you release, the gum will be white.  Note the time it takes for the gums to return to their normal color.  It should be pretty darn fast normally!


  • Dull eyes.  No sparkle, no shine.  


  • Overall demeanor.  Is your guy lethargic or depressed?


  • Increased heart rate.  This can sometimes happen with dehydration.  


  • Is your horse drinking normally?  This is the number one reason to hang buckets and fill them throughout the day.  Most horses have a drinking pattern, and you should know it.  Any deviation can indicate a problem.  




Your horse’s hydration is one key to his health.  Dehydration has many causes, including the following:


  • Excessive sweating
  • Lack of sweat despite normal sweat producing conditions
  • Gastrointestinal distress, constipation or diarrhea
  • Thumps
  • Tying up
  • Kidney disfunction


If you even suspect the beginning of dehydration, please call your Veterinarian immediately.  It can be dangerous and even lead to organ failure and laminitis.  Your Veterinarian can give you a plan for rehydration that may include IV fluids or introducing water to him slowly at first, and then being allowed to drink freely. 

What have your experiences been?