IMHO, 12' is too far apart. Horses and cows will need more restraint, even with a hot wire. If they get spooked, they will barge right through it. My neighbor just found out about that a week ago.
Also, save yourself some trouble and pound in the posts instead of concreteing them in. When replacement is needed, (because an animal, the neighbor kids, your tractor or a falling tree takes out one or more) it will be a lot easier.
You should plan on breaking this area into several smaller pastures so a field can heal after its all chewed up. And make your gates wide enough to get all current and future machinery through.
Also, save yourself some trouble and pound in the posts instead of concreteing them in. When replacement is needed, (because an animal, the neighbor kids, your tractor or a falling tree takes out one or more) it will be a lot easier.
You should plan on breaking this area into several smaller pastures so a field can heal after its all chewed up. And make your gates wide enough to get all current and future machinery through.