Question

Can I feed big bluestem hay to horses?

Answer

Big bluestem (Andropogon gerardii) is a warm-season grass that produces well, especially in summer.

Hay producers do not typically harvest big bluestem during its first year of growth, as this time is used to establish a high-quality stand. Instead, hay is baled the second year. Harvesting prior to development of seed heads ensures optimal nutrient density and regrowth potential. Once seed heads emerge, hay quality drops but yield increases.

Interest has stirred recently regarding the use of big bluestem for horses prone to metabolic disease and laminitis. Warm-season grasses, like big bluestem, generally have lower levels of nonstructural carbohydrates (NSC) than cool-season grasses. Further, they produce no fructan, the simple carbohydrate thought to play a role in triggering laminitis in predisposed horses. One study found that big bluestem forage grown in varying light conditions did not exceed 12% NSC, suggesting it could be useful in the diets of horses susceptible to laminitis.^*

In a more recent study conducted at Virginia Tech, voluntary intake of big bluestem hay was lower than that of more common cool-season hays, which also may be beneficial for horses with a propensity for metabolic problems such as obesity and laminitis.^**

Horses on all-forage diets should be offered a ration balancer or a high-quality vitamin and mineral supplement to ensure all nutrients are consumed in sufficient amounts.

^*Kephart, K.D., and D.R. Buxton. 1996. Nonstructural carbohydrates in cool- and warm-season perennial grasses adapted to shaded conditions. Research Summaries 85-86.

^**Ghajar, S.M., H. McKenzie, J. Fike, B. McIntosh, and B.F. Tracy. 2021. Evaluating digestibility and toxicity of native warm-season grasses for equines. Translational Animal Science 5:1-13.