About this item -When the imbalance of excess stress combine with high temperatures and humidity, horses begin to suffer the debilitating effects of anhydrosis. -No side effects have been reported from using this feed supplement. There are no ingredients in ONE AC that are known to cause a problem for pregnant and lactating mares. -No animal has tested positive for drugs while using ONE AC. -ONE AC is weight and work dependent and was designed for the average sized horse (950-110lbs). Therefore, for larger or smaller animals, the dosage needs to be adjusted. Add or subtract 1/2 tsp per day for every 100 lbs. over or under the designed minimum or maximum weight. -Field tested by Univ of Florida. Safely on the market for 15 years. See more product details