Protect your herds against disease with Compass Minerals(R) American Stockman(R) Se-90 trace mineralized salt blocks with selenium. Selenium is an antioxidant that promotes a healthy immune system and regulates an animal's ability to handle stress. This formula also adds essential levels of copper to the diet. Appropriate for bovine and equine herds. | American Stockman Se-90 Trace Mineralized Salt with Selenium Block | Size 50 lbs