Swollen glands in horses – Is it grass glands or grass mumps?


Swollen glands in horses mean you should call the vet if your horse has swollen glands or swelling in the throat latch or jaw area. It could be “no biggie” or “the barn is now under quarantine”. Only your vet can help you figure out what’s going on.


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Anatomy of the horse head and throat latch area.


The horse’s head is chock full of stuff that can get swollen, like lymph nodes and salivary glands. The ones to watch out for are the mandibular lymph nodes, the retropharyngeal lymph nodes, and the parotid salivary glands.


  • The mandibular lymph nodes are located between the lower jawbones.


  • The retropharyngeal lymph nodes are located near the throat latch.


  • The parotid salivary glands are between the base of the ear and the jaw.


  • The mandibular salivary glands are also along the upper jaw bone.


under a horse's jaw

Mandibular lymph nodes are between the jawbones. Also, if you have ever wondered what I look like, here I am! Lower left of the photo.


Reasons why a horse’s gland or node gets swollen


  • Local infection. The mandibular lymph nodes might be swollen if a tooth (or something else) is abscessed or otherwise infected. Of course, an infection is painful and needs the Vet’s attention. Many broken teeth and abscessed teeth create painful chewing, food dropping, and a foul smell coming from your horse’s nose and/or mouth.


  • Grass! Yes, grass. Some horses have a reaction to weeds or clover in the grass that causes the parotid salivary glands to go into overdrive. Removal from the grass for a day usually clears things up. More on the clover slobbers can be found here.


  • Grass glands or grass mumps is the term coined when grass causes those salivary glands to work overtime.


  • Something worse, like strangles. This highly contagious condition involves all sorts of swollen glands that can actually rupture. It’s accompanied by a fever and nasal discharge. I can’t stress this enough – it’s highly contagious and definitely needs a vet – pronto! Daily temperature checks and vital sign observations are key to catching all sorts of things early – including strangles.


horse jaw and neck area

You might find swelling along the throat latch area, or in between the jawbones.


Procedures if you find your horse has swollen glands


  • First, nobody panic.  A quick assessment of your horse’s vital signs, especially his temperature, gives you more information as to how your horse is actually feeling. 


  • Then back up and look at big-picture things.  Is your horse acting off or strange?  How are his nose and eyes?  Is he eating, drinking, peeing, and pooping as usual? 


  • Take a quick peek at the other horses in the area.  Do they have swollen throat latches?  Do any of them have a fever?


  • Has your horse changed paddocks or pastures lately that have given him new weeds to chew on?  Have you been to a horse show lately?


  • Check-in with your vet, just in case.


One last point to hammer home – knowing what’s normal, using your hands to inspect your horse’s whole body, and taking your horse’s temp daily will alert you to things before they go sideways badly.


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