What do I need to know about my horse's respiratory system?


Your horse’s respiratory system is amazing and complex, and technically, it’s on the inside of your horse, but what’s happening on the outside can give you a lot of information!  First let's take a look into the parts of your horse’s respiratory system and what to look for as you are grooming and riding.  The respiratory system of your horse has tons of functions:


  • Oxygen intake 
  • Getting rid of carbon dioxide
  • Immune functions against inhaled “stuff” like bacteria, viruses, fungi. 
  • Filtering out thrombi and emboli, which are fancy words for blood clots and air bubbles.  It’s not super ideal to have these in the lungs, but it beats having them in the brain. 
  • Thermoregulation - helping the horse maintain a normal body temperature.
  • Pain indicator - horses might increase respiration during times of stress or pain. 



It all starts at the nostrils.  Here your horse breathes in air, which incidentally can’t happen through his mouth.  Only the nose!  Look for discharge, blood, anything out of the ordinary.  Bugs, crust, and scabs can be found here.  Make sure to keep all hairs intact, as they help stop particles from entering your horse’s airway.  Use a damp sponge or soft cloth to clean the nostrils and remove crusty dusty stuff.  Any abnormal discharge or lack of normal discharge is a sign something is going on!  There is a duct that drains tears from you horse’s eyes to his nose, which on some occasions can become blocked. 



Look out for new, unusual, persistent, or weird discharge from your horse's nostrils. 


The flehmen response also happens here as the Jacobson’s Organ can swirl smells around.  The flehmen response is also a pain indicator, so it’s up to you to decide if your horse caught a stinky smell, or he’s having some pain.  For more on the flehmen response, read this captivating article here.  




Sinuses - these air pockets in the skull create a lot less weight for your horse to carry at the end of his neck!  Sinuses are often the location for infections, tumors, and dental issues, which usually create some sort of discharge and swelling to your horse’s face.  It’s important to recognize if these signs are from one nostril or both, as that can help your Veterinarian determine the exact source of the respiratory system problem.   I don’t have to tell you that this is painful.


Soft palate - this is an extension of the roof of your horse’s mouth (aka the hard palate).  The soft palate is below the epiglottis and doesn’t allow air from the mouth to the trachea.  It is possible for the soft palate to get out of place.  The epiglottis can also become entrapped. 



Not just for smooching.  Gotta pay attention, too. 


Pharynx - this divided into the trachea and the oesophagus and sits just above the larynx.  


Larynx - Commonly referred to as the voice box, which allows your horse to yell at your for his dinner.  The larynx is made up of several pieces of cartilage including the epiglottis.  The larynx is at the back of the throat and delineates the upper and lower respiratory tracts.  The larynx is the location for roaring, where some of the cartilage can’t get out of the way and created a lion like noise. It’s definitely a problem, as roaring can interfere with athletic performance.  


Trachea - The passage way to the lungs - where the magic happens as oxygen infuses blood!  The trachea splits into two bronchi, which spread out into bronchioles, which all make up the lungs.  


Lungs - These bad boys are responsible for loads of stuff - namely oxygen exchange.  Fun fact about horse lungs - an unfit horse will move the same volume of air as he will a year later when he is fit. The lungs are also the site of damage that can occur from respiratory diseases and ammonia in the barn.  Ammonia prevention and destruction is critical for lung health!  A minimally dusty environment is key, also, especially if your horse eats on his shavings.  



Ammonia smells are dangerous, but easily removed in the barn with Sweet PDZ. 


Diaphragm - The large muscle that inflates and deflates the lungs.  Interesting fact about the diaphragm - it works in rhythm with the gallop and canter.  When the hind legs are under your horse, the diaphragm is contracted and your horse inhales.  As the stride lengthens, the diaphragm is pushed forward and your horse exhales.  Pretty spiffy!


What to notice about your horse during grooming and riding when it comes to his respiratory system:


  • Goop and discharge around the nose.  
  • Weird noises during inhalation, exhalation, or both. 
  • A changed respiratory rate at rest. The normal resting rate is about 8-12 breaths per minute, where one inhale and one exhale equal one breath.  Learn more about normal vital signs for horses here. 
  • Coughing - this can signal lung diseases and conditions like heaves.  It’s not normal or good when a horse coughs. 
  • The flehmen response - is your horse uncomfortable?



Have one of these in your Vet Kit.  


Any abnormal respiratory issues warrant a call to the Veterinarian right away!  Have you had a horse with respiratory problems?