Psyllium is typically used to treat which condition in horses?

Psyllium is a natural dietary supplement commonly used in horses to help expel sand from the gastrointestinal tract, making it particularly effective in treating sand colic. This condition occurs when horses ingest sand while grazing, which can lead to a buildup of sand in the intestines, causing blockages and discomfort. Psyllium works by absorbing water and forming a gel-like substance in the intestines, which aids in the passage of sand and other debris, promoting healthy digestion and reducing the risk of colic.

While the other conditions listed may be serious, they are not typically treated with psyllium. Colic due to overeating generally requires different interventions such as fasting, fluid therapy, or medications. Equine herpesvirus infection focuses on antiviral treatments and supportive care, whereas obesity management usually involves dietary changes and exercise rather than psyllium supplementation. Thus, psyllium's primary role in equine health is specifically related to managing sand colic effectively.