Fence Building

There is but one fence and electrified high tensile is its name! There is a certain technology you have to follow, but there is considerable latitude also. A three wire high tensile fence is legal (in West Virginia), if properly built. Posts may be set 75 feet or more apart, but must be close enough to follow the contour of the ground. It is quite adequate to keep bulls and cows in heat separated, the only fence that will do so. However, cattle can be stampeded through it, and new born calves will fumble through, apparently they do not understand the wire is the cause of their pain.

Let’s discuss how it works in general terms. The controller loads a capacitor with electricity, this is allowed to run into the fence for about three thousandths of a second. If anything is in contact with the fence and the ground it will get shocked at this point. After the very brief period the fence is unloaded, that is, the charge is allowed to drain away into the ground. This will repeat in about three-fourths of a second. The electrical quantity that causes pain is the energy that passes from the fence wire to the ground through the animal (or unfortunate person), not the voltage. Energy is measured in joules (pronounced the way West Virginians pronounce “jewels” - jewlz).

The capacitor mentioned previously determines how much energy the charger will hold. Typical values are 8 to 15 joules for a 110 volt charger. The charge is limited by the capacitor in the charger. This is safe, that much electrical shock will not damage your body. My daughter worked in the Cardiac Care unit at Ruby Memorial Hospital, so I asked her what charge was used to restart a person’s heart. She told me 450 joules. So there seems to be a considerable margin for safety. I don’t recommend touching an electric fence while standing barefoot in a stream, of course. A charge from considerably less than fifteen joules is an emotional experience that will be remembered for a long time, I can assure you! The idea is for the fence to cause pain, so the animal will avoid it. You don’t want to hurt people or hurt or damage animals.

Several things affect the amount of energy that a charger actually supplies to the animal. One is the quality of the insulation. The polyethylene and ceramic insulators available are excellent, in effect allowing no charge to leak off. Another is loading by grass or brush. This is often significant, and so one should place the lowest wire17 (or a little more) inches off the ground for cattle, unless there is some special reason. This height would be a joke for barbed wire, the cattle would lift it with their heads and go right under. Keeping the bottom wire up is one of the hardest things for someone used to building barbed wire fences has to learn. I know, it took me two decades! This height also encourages cattle to eat the grass under the fence, an important consideration. You don’t want to supply the labor to trim it out if the animals will do it. If the wire touches the ground, or a metal post, serious leaks will occur.

Your “fence tester” reads in kv (kilovolts), because it is difficult to measure joules, and once the charge is in the fence, the energy (or pain) delivered in a short circuit (you or the animal) is about proportional to the voltage. The animal stands in “bare feet” on the ground. I’ve never seen the ground so dry that they challenge electric fence, but I understand this is a problem in the arid West. You wear shoes or boots, which are good insulators, so you only get full energy when you are on a knee or sitting on the ground. If you wear lined leather gloves of the sort ordinarily used in winter you can handle all but a very hot fence with your hands.

I never use metal posts – wood for permanent and fiberglass for temporary, corners are larger posts set in concrete with no braces. Or drive six-inch posts on firm ground. More than three wires are best for approaches to pens where you work cattle, where you plan to wean feeder calves, and along the road where cows may be with very young calves. In these areas we use six wires, posts at about twelve feet, and in some areas “stiffners,” the “T” shaped fiberglass rods with notches, halfway between posts. Make your own “clips” from short pieces of wire left over from fences. The ones you purchase do not last very long. Cows will try to keep their baby calves away from 2 or 3 wire electric fence, but once in a while they will get through. It is best to build a more secure fence (six wirres) if you plan to have new born calves along the road. When they escape in other directions they will come back through the hot fence. Only a small fraction ever get through, and even those learn very quickly. Occasionally one will get stuck on the wrong side, so look for them when you feed.

If you buy animals that are not used to an electric fence, you have to train them. Put them in a lot that is secure, and put an electric fence across it. A temporary string fence is OK. Feed on one side and put the new animals on that side. They will learn what electricity is, and will approach all fences more gingerly. If a few get through, let them remain on the second side while you feed on the first side. Let them get hungry and try it again. The way a bovine checks the fence is by touching it with its nose, the most sensitive part of its body. An animal which is familiar with electric fence will be easier to control with other kinds of fence, too.

You need 2 to 2.5 kv on the fence to control animals. More is better. This is a fair jolt for you, too, but your shoes help insulate. Use 4.0 kv or better to train. Once they are trained, they do not challenge a fence for weeks, and if you have a gate that uses wires and hooks, they can be hard to get through the gate when you want to move them. The tube gates that are widely used work much better for getting animals from one field to another.

Internal fences on our place are all two wire, the second one mainly for a safety factor. Fences through a woods are not put directly on trees, because trees grow over the insulators or pull nails through the polyethylene insulators and let the wires drop. We use treated 2x4 “ insulator boards” to space the wires like they are on posts, and spike them to the trees through holes cut in the board the size of the spikes drilled through the 2x4’s. (Use junk trees, because the tree must be cut above the top nail for timber.) Do not drive the spikes all the way in, leave an inch or so for tree growth. These “insulator boards” are made at the house of scrap treated lumber on rainy days, and kept for use when needed.

We use barbed wire only in places too isolated to reach with electric fence. The back side of our farm is a strip mine high wall, and we need a few roads fenced where the miners left a road to the isolated hill top. We do not use high tensile, non-electrified fence, due to the necessity of keeping it very tight. For sorting pens we use high woven wire with posts at ten to twelve foot intervals. Electrified fence is not suitable for crowding animals. Even if it is made tight enough so they can’t force their way through, the electrical shocks would make them too wild to handle. We also use woven wire on the road side of the field where calves spend the first two weeks.

Temporary fence can be made with “Polywire” string and fiberglass rods for posts. The Polywire is polypropylene (the plastic used for ropes) with several strands of stainless steel woven in to cary electricity. I always use two strands. The conductivity is not as good as the standard wire, so you have a limit as to how long a fence can be made with it and still be effective. I can’t advise on this distance, because it depends on the charge on the fence you attach it to.

Two uses we have made of temporary fence are to isolate the bales in one corner of the meadow while pasturing it and second to funnel animals into an alleyway. Longer temporary fence can be made with fine gage wire. Either can be wound up effectively on the plastic reels sold to wind longer extension cords on.

To be secure when animals are under stress, such as a sorting lot, the best choice is woven wire. I believe the final pen before a cattle chute for working or loading should be made from two inch lumber and be high enough to prevent cattle from jumping over. Five feet four inches will hold all but the most wild animals. The posts should be ten feet apart or less for four board 2x 8 fences in such a lot.

Gates for sloping ground can be a problem. You want to set posts vertically, but the gate, if it is square, does not adapt to the slope of the hill. You can get around this by making a gate yourself, using hardwood, preferably white oak since it has the best rot resistance. Use a single 3/8 or 7/16 bolt in each end of the horizontal board and don’t tighten the bolts up to the point they prevent the end of the gate from being lifted. Set the post the gate is to be hinged to first, and tie to it loosely with wire or good rope. Then set the other posts the outer end will have to contact. This is necessary because the width of the gate will change as the outer end goes up or down. This isn’t beautiful, but it works. In situations like this you need to put (very small) gravel in the walkway, because it will erode badly when cattle go through it in wet weather.