Several factors affect horse pasture stocking rates

Iowa State University Extension
Horses stand on green pasture grass.

AMES, Iowa – Due to warmer and drier weather this summer, it is even more critical to understand pasture quality and how to use that pasture to support healthy horses. 

Several factors can determine how many horses one can keep on pasture, according to Peggy Auwerda, associate professor in animal science and extension equine specialist at Iowa State University. They include forage species, season of the year, environmental moisture, fertilization and length of time horses have access to the pasture.

In simple terms, horse stocking can be summarized as how much pasture your horse needs to sustain life and how much life the pasture has to give. 

Auwerda recently wrote an article and chart for the “Acreage Living Newsletter” highlighting horse pasture stocking rates. 

“Acreage required depends on the age and status of the horse. Status refers to if the horse is at maintenance, growing, lactating, a gestating mare or used for riding or driving activities. Each of these will have different nutritional requirements,” said Auwerda. “Then the quality and size of the pasture have to be considered. Quality is influenced by forage species, season of the year, environmental moisture and fertilization.”

Some forage species produce greater tonnage per acre, while others produce less. For example, Kentucky bluegrass is a good pasture plant but does not produce as much tonnage as other pasture species such as orchardgrass or smooth bromegrass. Utilizing horse factors, type of forage and type of grazing (continuous or rotational), one can calculate the stocking rate of the pasture. 

Stocking rates provide information on the number of horses a pasture can carry in a month.

Other articles in the May edition of Acreage Living include online food safety training for home-based food operators in Iowa, controlling weeds in the home lawn and garden, and using pesticides safely with the FieldWatch registry.