Join Date: Oct 2009
Location: Just south of sanity
The terms "laminitis" and "founder" are used interchangeably but they're not the same thing, although they are related.
Laminitis is caused by the disruption of blood flow to the laminae in a horse's feet. The laminae secure the coffin bone to the hoof wall. When a horse develops laminitis, the laminae become inflamed, which can separate the bone and hoof wall. This may or may not present with a rotation of the coffin bone.
Founder usually refers to a chronic (long-term) condition associated with rotation of the coffin bone, whereas acute laminitis refers to symptoms associated with a sudden initial attack, including pain and inflammation of the laminae, but not necessarily rotation.
Not all horses who get laminitis will founder, but all horses with founder will have had laminitis, because one is a condition of the other.