Horses standing in a misty paddock at sunrise
Guide · 3 min read

Pneumonia in Horses: What to Know

First published May 2013 · Revised 2026

Pneumonia takes various forms, but as an inflammatory illness of the lung it can be life-threatening for a horse, because it attacks the ability to pull oxygen out of the air.

First, what's happening

Fluid where the air should be.

Inside the lungs, tiny sacs do the work of collecting oxygen from every breath. With pneumonia, those sacs fill with fluid. Once saturated, they can't collect enough oxygen to support the horse's body, and a body deprived of oxygen long enough doesn't survive it. That's why this one is never a wait-and-see condition.

Get the vet involved early

A horse showing the signs below should be examined promptly. Diagnosis often involves x-rays, sonograms, and sometimes inspection of mucus or phlegm expelled from the lungs and air passages. That's vet work, and the sooner it starts, the better.

The symptoms
Difficulty breathing
Sneezing
Wheezing
Coughing
Sputtering
Weight loss
Green-tinted discharge from the nose

The one piece of good news: pneumonia is not contagious from one horse to another. It can affect horses of any age, though it's more prevalent among foals and geriatric horses.

Where it comes from

Three common types, three different sources.

Most common
Viral

Viruses leave the respiratory system vulnerable, opening the door for pneumonia to develop.

From the barn
Bacterial

Bacteria riding on inhaled dust from feed, bedding, stables, or working surfaces, carried into compromised airways.

From the hay
Fungal

A weakened respiratory system inhales fungal spores, usually from moldy, poor-quality hay or other sources.

Two of the three start the same way: in a respiratory system that's already weakened. You can manage the barn and the hay directly. The horse's own defenses are what the daily nutrition is for.

Clinical reference: Veterinary Clinics of North America, Equine Practice.

Daily support for horses

Support the lungs from the inside.

Sprouted Granules, 2 lb bag
Add to feed · daily

Sprouted Granules, 2 lb

The live superfood that supports the immune system the lungs depend on, every day, in the feed.

600 to 750 lbs3 level tsp
750 to 1,000 lbs4 level tsp
1,001 to 1,250 lbs5 level tsp
1,251 to 1,500 lbs6 level tsp
Ox-E 8 oz Refiller
Orally · twice daily

Ox-E Drops, 8 oz Refiller

Add 20 drops to 10 to 15 cc of filtered water in a large oral syringe, and squirt slowly along the teeth-line so your horse can swallow comfortably. Naturally alkaline, supporting a healthy pH and immune function. For a horse, the 8 oz Refiller is the practical size.

Both are covered by the 120-Day Worry-Free Guarantee: up to four months to see the difference in your own horse. Bergen, an Arabian Paint who struggled for every breath with heaves, is the horse that brought Kara to Nzymes: read his story, in her words.

Breathing is the one job that never gets a day off.
Keep that system fed.

Questions horse owners ask
Is pneumonia contagious between horses?

No. Pneumonia in horses is not contagious from one horse to another. It can affect horses of any age, though it's more prevalent among foals and geriatric horses.

What are the symptoms?

Difficulty breathing, sneezing, wheezing, coughing, sputtering, weight loss, and green-tinted discharge from the nose. A horse showing these signs should be seen by a vet promptly; pneumonia can be life-threatening.

What are the three common types?

Viral is the most common, where viruses leave the respiratory system vulnerable. Bacterial comes from bacteria inhaled with dust from feed, bedding, stables, or working surfaces. Fungal usually occurs when a weakened respiratory system inhales spores from moldy, poor-quality hay.

How is it diagnosed?

Diagnosis often involves x-rays, sonograms, and sometimes inspection of mucus or phlegm expelled from the lungs and air passages. That's vet work, and it shouldn't wait.

How can nutrition support the respiratory system?

Two products, given daily: Sprouted Granules support the immune system the lungs depend on, and Ox-E Drops given orally support a healthy pH and immune function. Both are covered by the 120-Day Worry-Free Guarantee.

Worried about a cough that won't quit?

Kara's own horse fought for his breath. She knows this road from the barn side.

Kara is the equine specialist on our customer care team, and Bergen, the horse in the story above, is hers. Tell her what you're hearing and seeing, and she'll tell you honestly where to start. Read Kara's story →

The consultation is free, and it always will be.

1-877-816-6500 · Orders & quick questions
Kara and Perry out riding on their farm in Saskatchewan
Kara · Equine specialist