Feeding performance horses varies greatly from feeding horses that are just sitting in the pasture. Horses with different workloads have different nutritional needs that need to be met. A good place to look for information on what to feed you horse or how much is the internet, your veterinarian, or the state Extension Equine Specialist. The good thing about being able to call and talk to someone is that if you have any questions your vet or Equine Specialist should be able to answer those questions immediately. However if you know how hard your horse works, what kind of grass or hay he has available, and of any other needs Purina has an interactive feature on its website to help you choose the feed that best fits your horses life style.