PRO BI™ is a biological feed additive designed to maximize digestive efficiency. An animal’s beneficial intestinal bacteria can be destroyed or depleted and the pH of their environment can be altered during times of stress. Competition, travel, breeding, treatment with antibiotics, de-wormers and other medications can cause this stress. Stress can also be created by alterations of weather, environment, feed, and water. PRO BI™ does not need to be refrigerated. It has NO EXPIRATION DATE.