Boost Immune System We offer two different supplements that boost the immune system Necessity Necessity includes 21 vitamins, trace minerals and amino acids to boost the immune system. The combination of vitamin E and selenium in Necessity assures you that your horses immune system will be strong and keep them healthy. Necessity is also available with glucosamine and with glucosamine & MSM. Click here to learn more about Necessity Cellarator Cellarator is a cutting edge feed supplement that increases both red and white blood cells in the body. White and red blood cells help fight infections and keeps the horse healthy. Cellarator is also available with glucosamine (Cellarator Flex). Click here to learn more about Cellarator