Use copper or galvanized steel for your earth electrode. Insulated bitumen steel posts don't work. Some say scratch off the black coating - that won't work either. Sorry, the single live wire system won't work for you. You must use the fence earth return wire system .
Animals get a kick by touching the live and earth wires simultaneously.
This kind of fence has very little loss and is ideal for restraining bulls and for vermin control. Use proper fence insulators. Replace porcelain insulators if they are crazed. If you decide to make your own insulators keep plastic thicknesses above 6mm and tracking distance across the surface of the insulator above 30mm. For insulated cables use properly designed high voltage ones.