Cool-season grasses are those that obviously grow best in early spring and early fall. They include grasses such as bluegrass, fescue, perennial ryegrass, orchardgrass, and bromegrass. Legumes such as alfalfa and clover can be incorporated into either cool or warm season grass stands to improve the pasture quality, particularly for protein and calcium content. In more sandy soils, a grass that produces a thick sod is more desirable to prevent hoof damage. Fescue is the most desirable species to produce a thick sod, but should not be used in most cases if pregnant mares may be grazing.
Bluegrass is usually the most effective pasture species across all classes of horses.
The pasture should be subdivided into manageable paddocks. Paddock size will vary from one farm to another, but the optimum size is one that can be grazed in 3 to 6 days before horses are rotated to the next paddock. Horses are very selective grazers and will graze the most desirable grass very heavily and allow the undesirable plants to grow and reproduce in the pasture. Eventually, the desirable plants are eliminated and the less desirable ones populate the pasture. Grazing and clipping are used to maintain pasture quality.