Stool, also called manure or feces, is the solid or semi-solid waste material remaining after the digestive tract has extracted water and nutrients from ingested feed. In healthy adult horses, stool appears as distinct, formed balls of roughly uniform size, olive to dark brown in color, and with a mild odor of fermented fiber. Consistency and frequency vary with diet: horses on fresh pasture produce softer, greener stool, while those on dry hay produce drier, firmer fecal balls.
Monitoring stool is one of the simplest daily health checks available to horse owners. Changes in output — reduced manure production, abnormally dry or hard balls, diarrhea, or foul-smelling loose stool — frequently precede or accompany colic episodes, intestinal impaction, or infectious enteritis. A horse that has not produced stool in more than 12 hours warrants immediate veterinary assessment, as impaction impaction risk when output stops carries serious risk if untreated.
Parasite management programs rely in part on fecal egg counts extracted from fresh stool samples; routine fecal testing is the evidence-based foundation for fecal egg count sampling and helps avoid the resistance problems associated with calendar-based anthelmintic rotation.
Stool in the foal carries diagnostic significance beyond that in adults: meconium (first stool) retained in a newborn foal signals a potentially life-threatening obstruction. Normal meconium passage within the first few hours of life is a key neonatal milestone.