Purina® Outlast™ Gastric Support Supplement is formulated to support gastric health and proper pH. It is estimated that up to 90 percent of active horses experience gastric discomfort, a­ffecting health, attitude and performance. Common activities including stall confinement, exercise, transportation, weaning and few environments such as events and shows are known to cause stress and gastric discomfort. Purina® Outlast™ Gastric Support Supplement was developed by our Ph.D. Equine Nutritionists to support a healthy gastric environment. View Guaranteed Analysis and more information on this product.