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


Rapid Breathing, Flaring Nostrils at Rest (Not after Exercise)


Breathing rate is regulated by the brainstem, which responds to the levels of CO2 and Oxygen present in the blood. Rapid breathing is the body's attempt to increase gas exchange in the lungs, it is also a response to overheating, stress and pain.

Rapid breathing that is not associated with recent exercise is commonly seen in horses suffering from severe disease processes including heaves Recurrent Airway Obstruction (RAO), allergic reaction (anaphylaxis), exhaustion or heat stroke. Horses in end-stage shock that is caused by any number of severe illnesses or injuries (major blood loss, pain, metabolic problems, or heart failure) may breathe or pant heavily.

  • 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

Horses exhibiting this sign may be experiencing a life-threatening crisis. Keep the horse quiet and calm and contact your vet immediately. Perform the Whole Horse Exam, paying particular attention rectal temperature, and to the presence or absence of excessive respiratory noise. this may give a clue as to whether there is an upper airway obstruction. Assess the horse's gum color, which reflect tissue oxygenation status. Are they bluish, pink or red? Regardless, this is a veterinary emergency.

your vet's role

Your vet uses history and physical exam findings to try to determine what is responsible for the rapid breathing.
Questions Your Vet Might Ask:
  • When did you first notice this?
  • What is the horse's age, sex, breed and history?
  • What is the horse's heart rate and respiratory rate?
  • Does the horse's appetite and attitude seem normal?
  • Have you noticed this happen before?
  • Has the horse received any medications or new feeds or supplements?
  • Do you think there have been changes to the horse's environment or feeding?
  • Have you given any medications to the horse, what and when?
  • What are the results of the Whole Horse Exam (WHE)?
  • How hot and humid is the weather?
  • Do you have medications of any kind?

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
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Treatments Your Vet May Recommend

A way to resolve the condition or diagnosis. Resolving the underlying cause or treating the signs of disease (symptomatic treatment)

Very Common
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Author: Doug Thal DVM Dipl. ABVP