Ultralyx 10401 064576 Rabon Fly Control Block Cattle & Horses, 33.3 lb Convenient free choice Fly control for weaned cattle and horses on pasture Highly palatable source of natural protein energy minerals and vitamins with no additional salt added Contains ribbon oral larvacide for the control of fecal flies in the manure of treated animals One block will supplement 10 Average cattle or horses for Approx. 1 week Made in the USA