Conditions or ailments that are the cause of a problem that you see - your observation.

Your vet may diagnose

Foal Pneumonia, Rhodococcus equi

Synonyms: Summer Pneumonia, Rattles


This is a common and severe foal pneumonia that typically affects foals at 6 weeks to a few months of age. The agent causes large abscesses to form in the lung. These require weeks of treatment with specific antibiotics that are able to penetrate into the infection. This disease is classically seen in hot, dry and dusty climates and facilities. It is more common in crowded conditions at breeding farms.

The disease can be surprisingly hard to diagnose. Routine blood work is not always diagnostic. Chest x-ray can visualize the lesions and chest ultrasound is also useful.

Affected foals develop lung abscesses that are impossible to treat without the use of particular antibiotics for long-term. These antibiotics must not only have the chemical characteristics to kill the organism, but must also be able to penetrate into the center of the abscesses.

my role


I might observe

You might make these observations when a horse has this condition.

Very Common
Less Common
more observations

Questions To Ask Your Vet:
  • What are the ways we can reduce incidence of the problem in the future?

In my experience at breeding farms, the use of R. equi hyperimmune plasma in newborn foals has reduced the incidence of this problem significantly.

further reading & resources

Author: Doug Thal DVM Dipl. ABVP