For the fences in a pivot I string a high tensil wire. Some springs help. Set a post back about 20 steps from each wherl track. Put wire about height of center of tires. At the center of the pivot, start the wire with a post at one side of the pivot pad, not the center. That way only a few towers are on the fence at any time. Use a 6 joule fencer with a good ground, so cows have a healthy respect for the fence. You can hook a 120 volt outlet to the control transformer in the pivot panel to power the fencer (if pivot runs off power lines)
At each tower, i drilled a hole in the bracket to the gear box. Put a bolt about 4 inches long in the hole with a nut on each side of the support & the bolt head sticking towards the center gear box. Cut a 5/8" tod about 2 inches shorter thab the didtance between the ends of the 2 bolts. In the middle of the rod, i welded a flat iron abt 2" long to support it from the motor bolt via a insulator made from a strip cut out if the side of a 4" schedule 40 pvc pipe. At the ends of the rod, i weld on a washer anout 4 inches from the end. Cut a piece od 1" schedule 40 pvc pipe about 9 inches long to put over the nolt heads & end of the rods for insulators.
Fence this way usually works if you put wire higher, get cows accustomed to it, then lower it so pivot can go over it. If cows get to jumping, put on a second wire.then beside each wheel track make a hinged post. 3/4" fiberglass fence post works good. Can just drill a hole in the bottom for it to hinge on. But a short piece of tubbing over it at hinge might make it last longer. Part you burry should not be able to turn in ground. One piece of steel fence post don't work real well. Then put bottom wire a little lower. When tower gets there, tire pushes on lower wire that starts leaning hinge post over. Tension on fence wires will hold post upright. Probbly will need a few springs in both wires when using 2 wires.
This usually works, but every so often the wire died seem to get caught, probbly at least once a year.
