What you see. The starting point for addressing any equine health related issue is your observation.


Fever, Rectal Temperature Greater than 101.5 (in Adult)


Fever is caused by a center in the hypothalamus of the brain changing the set point for the body's normal temperature. Fever has an important purpose in fighting infection and should not always be reduced. All fevers should be monitored, but not all of them should be treated.

A normal temperature for an adult horse is 98-101 degrees Fahrenheit. A mild elevation in temperature (up to 102 degrees F) can be due to a trailer ride in hot weather, recent exercise, or excessive blanketing. It is also a classic indication of the immune system responding to viral or microbial infection.

  • Code Red

    Call Your Vet Immediately, Even Outside Business Hours
You also might be observing
Very Common
Less Common
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your role


What To Do

Assess the horse's general health using the Whole Horse Exam (WHE), paying particular attention to their attitude and appetite, and look for other signs of illness.

If your horse has a mild fever or you believe that it may be transient (related to exercise or trailering in hot weather), you can monitor the horse and reassess their temperature in an hour.

However, if the fever persists or your horse is showing other signs of illness, you should immediately contact your vet to discuss your findings and concerns.

your vet's role

Your vet will start with a careful history, considering the predisposing factors. Of particular interest to us is recent travel and exposure to other horses. A physical exam suggests body systems involved and blood work and other diagnostics help refine the diagnosis.
Questions Your Vet Might Ask:
  • What is the horse's vaccination status?
  • What is the horse's rectal temperature?
  • When did you first notice this?
  • What is the horse's veterinary and travel history?
  • Has the horse (or any other horses in contact with this one) been exposed to other horses from off p
  • Are other horses exhibiting similar signs?
  • Do you notice other signs?
  • Do you notice swelling around the jaw or throat?
  • What are the results of the Whole Horse Exam (WHE)?

Diagnoses Your Vet May Consider

The cause of the problem. These are conditions or ailments that are the cause of the observations you make.

Very Common
Less Common
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Author: Doug Thal DVM Dipl. ABVP