How do I design and manage a safe pasture for horses?

A safe horse pasture is one that provides adequate grazing space for the number of horses using it, is free of plants and objects that can injure or poison horses, is fenced with horse-appropriate fencing in good repair, and has water and shade accessible from all areas. Designing and maintaining a pasture that meets all of those standards requires attention to detail at the outset and ongoing management as conditions change seasonally. Stocking density is the pasture management factor with the greatest influence on both the horses' health and the pasture's long-term viability. Too many horses on too little acreage creates a muddy, manure-dense environment that supports parasites, promotes hoof problems, destroys the grass cover, and creates social stress among horses competing for limited space. Toxic plant identification and removal is a safety responsibility that every horse pasture manager should take seriously. Many plants that grow commonly in fields and fence lines are toxic to horses — some causing acute poisoning that can be fatal, others causing cumulative damage over repeated exposures. Identifying the plants present in a pasture and confirming that none of them are toxic is a baseline safety step for any new pasture and a periodic maintenance responsibility for established ones. Shade and shelter in the pasture are welfare requirements in hot climates and helpful in most climates. A horse that has no access to shade in summer heat will experience heat stress during the hottest parts of the day, and providing shade structures or access to tree-covered areas significantly reduces that stress.