Here are some possibilities:
* Downer: This is a general term for a horse that is unable to rise from a recumbent (lying down) position.
* Recumbent: This simply means lying down, but it is often used to describe a horse that is unable to rise.
* Down with colic: This refers specifically to a horse that is lying down due to colic (abdominal pain).
* Downer syndrome: This refers to a specific condition that causes horses to become recumbent and unable to rise. It is often associated with metabolic disorders.
It's important to note that any time a horse is down and unable to get up, it is a medical emergency. It's crucial to contact a veterinarian immediately to assess the situation and determine the cause.
Here are some additional factors that might influence the specific term used:
* The cause of the horse's recumbency: The term might be more specific based on the underlying condition, like a neurological disorder or a fracture.
* The severity of the situation: A horse that is simply resting might be referred to as "lying down," while a horse that is struggling to breathe or showing signs of distress would be considered a "downer" or "recumbent."
Ultimately, the most important thing is to ensure the horse receives prompt veterinary attention.