Forage and Pasture Management for Laminitic Horses

In the past, many cases of laminitis have been of mysterious origin. Recent investigations in veterinary medicine, coupled with the availability of new techniques for analyzing hydrolyzable carbohydrates in forage may provide evidence to solve some of these mysteries. Fructan has been shown to be capable of inducing laminitis in clinical studies. Insulin resistance, a primary feature of Equine Metabolic Syndrome, has consequences to vascular tissue that help explain why many horses with hyperinsulinemia suffer with chronic laminitis. High levels of fructan, as well as simple sugars, may be found in grass that is subjected to stress from rapidly changing environmental conditions. Stressed grass, and hay made from such grass, may contain up to 35% (dm) sugar, starch and fructan, which comprise a fraction defined as Non Structural Carbohydrates (NSC). The factors that may affect the NSC content of forage include: genus and specie of the forage, light intensity and duration, temperature, nutrient and water status, stage of growth, and grazing management. This paper is an introduction to the principles of plant physiology that affect the NSC content of forage, in hopes this knowledge can offer veterinarians some practical solutions for the feeding and management of laminitic horses under their care.