Some farmers buy fences to pen livestock while others buy fences to keep predators and other wildlife out. Whatever the purpose, there are many ways to pay far more than necessary to build a fence well. We consulted experts to find out how to save money.

Fifty years ago, fence construction was straightforward. Here in the Northeast, it usually involved buying woven wire, locust posts, some staples, a post hole digger and a fence stretcher. Having a friend or a neighbor to help was a bonus.

Fed by a growing interest in intensive and rotational grazing systems in the late 1980s, fence construction gained quite a few options, including high tensile wire, polywire temporary fencing, and pressure-treated and step-in posts.

Thirty years later, farmers and fence builders alike know there is no single best fence solution.

Colin Kennard (far right) and the Wellscroft Fence Systems crew is ready to handle another job.

Photo: cafotodigital/istock

High-tensile fence

Wire-forwire, post-for-post, the most inexpensive livestock containment system available is high-tensile fencing. “The cheapest perimeter fencing is high-tensile wire,” said Mike Baker, a Cornell University Extension beef specialist. “It will cost $2 a foot if it is installed and $1 a foot if you do it yourself.”

The number of wires to hang varies, depending on what is on the other side of the fence. Baker thinks three wires are too risky when fencing stock away from major roads or homes.

In general, Baker recommended four- to five-wire fences when beef cattle are involved.

A dead-man diagonal brace is used in a corner with Smart Net Anti-deer netting.

Another factor is livestock behavior. How likely will animals bolt when they sense a predator nearby or when startled by thunder or lightning? “Cows with calves tend to be calm, while yearling cattle are a lot spookier,” Baker said. In his experience, they will run right through three wires, even when wires are electrified.

Colin Kennard, operations manager of Wellscroft Fence Systems LLC of Harrisville, New Hampshire, who is also the second generation involved in his family’s livestock fence business, said dairymen will need the same number of wires to contain their animals. “Dairy cattle do respect fences,” Kennard said. “They are usually easier to contain than beef cattle. Dairy cattle can be contained with two high-tensile wires, whereas beef usually require three to four wires.” Similarly, he tells customers who fence sheep in larger pastures that five- to seven-wire fences are the way to go. For internal fencing, such as rotational grazing paddocks, he recommends use of electric netting.

Going postal

Locust posts last a long time. Baker said he’s seen a few 90-year-old fences with original locust posts still standing. The trick is to buy the wood green and hang the fence before posts harden.

Avoid cedar posts though. “They are good for seven to 15 years at best,” Kennard said.

Locust posts can be hard to come by, Kennard said, which makes pressure-treated lodge pole a good, long-lasting alternative. It is not unreasonable to expect them to last 30 to 40 years.

Optimally, wood posts in corners and ends should be 5 to 6 inches in diameter. Stay away from the square posts because they split more easily than round ones.

When recommending wood, Kennard suggested using pressure-treated lodge pole pine or southern yellow pine.

Use a post driver to pound posts into the ground. “Pounded posts are three to four times stronger than posts placed in holes dug with an augur,” he said. “Augurs create holes larger than most post diameters and require filling around the post, which tends to create wiggle room.”

Corners should feature either H-braces or diagonal braces and high-tensile fence wire should be equipped with heavy-duty springs. “Otherwise, end posts will lean, the corners will lean and when the ground heaves, standing fence life can drop to three to four years.”

When deciding which kind of post to use – wood, fiberglass or steel – be aware each material has a best use. “Fiberglass posts are a good choice for long straightaways,” he said. “When it comes to changes in terrain or corners, wood or steel posts are needed.”

Fiberglass post manufacturers coat their products to prevent splintering when they are planted into the ground. “There are some step-in poly posts that are pretty popular because they are very portable, lightweight and easily installed by stepping on the brackets attached near their bottoms,” Baker said.

Wires and tapes

The best physical barrier is also the most expensive: square woven wire. Since it is not electrified, if the power goes out, fence integrity remains.

Its downsides are that it costs twice as much as high-tensile wire; the posts must be placed closer together than high-tensile systems, requiring more of them to cover the same area; and it requires more wire to cover the same area. “If a tree falls on it, it can be a mess to repair,” Baker said.

Barbed wire seems to have all but disappeared from the Northeast, though it remains a mainstay in extensive grazing situations in the High Plains and the far West.

Baker said that barbed wire is literally a pain to work with and requires just as many posts as woven wire does. In fact, it also requires steel posts, although, if it is electrified, use of wooden ones is indicated. Barbed wire’s costs lie somewhere between high-tensile and woven wire fences.

The most inexpensive fence material – polywire with either copper or aluminum wires – is unsuitable for perimeter fencing because of its light weight. “Once cattle are trained, though, it becomes a good handling aid,” Baker said.

Tape with aluminum or copper wires is more visible and stronger than twisted or braided polywire. It is also good for use as a semipermanent, interior fence when put up in the spring.

Electric fences

For most animals, all it takes is one or two shocks to teach them to stay away from fence lines. Any livestock that do not respect the jolt that a hot wire provides should be culled.

To assure hot-wire effectiveness, farmers should place charged wires at the nose height of penned livestock. Then they must run enough voltage through the wire to give animals a jolt sufficient enough for them to learn to respect the fence.

When using trees as posts, attach insulators to wood boards to prevent the trees from growing around the insulator.

Kennard said 3,000 to 4,000 volts is sufficient to contain cattle. “They are heavy and their hooves are on the ground, which makes them well-grounded, unlike chickens or turkeys, whose claws deliver far less ground contact,” he said.

Effective poultry voltage ranges from 4,000 to 5,000 volts. Poultry netting is a good way to protect birds. It usually features a 42- to 48-inch high, 12-strand polywire with 3-inch vertical spacing. “Some netting offers 2-inch vertical spacing at ground level to prevent entry by small predators,” he said.

Fencing critters out

Keeping larger wildlife out of farm spaces requires higher fences, different fence materials and more posts. The strategy is different than that for keeping animals in.

In orchards, an 8-foot woven wire fence – using 12.5- to 14-gauge wire – hung on 5- to 6-inch wooden posts should deliver 100 percent deer exclusion.

For bears, increase post placement to 20-foot spacing. Line posts should be 4 to 5 inches in diameter and sunk to a 3-foot depth, while corners should be placed 4 feet into the soil.

Snow and weeds are the real enemies of electric fences. Snow acts like an insulator, significantly reducing the charge. Weeds under fences can short them out.

Keep weeds cut under electric fences. “If your farm is located in an area with heavy snowfalls, it is a good idea to keep a separate enclosure surrounded by a strong, nonelectric fence to keep livestock penned during the winter,” Kennard said.


There are three things necessary to building a good fence, said J.C. Remsberg, who co-owns Valley Farm Supply in New Providence, Pennsylvania, with his wife. “They are the fence itself, an energizer and a good grounding system.”

The energizer market has changed considerably over the years. “Old-style energizers use capacitors to hold a charge of energy and release it,” Remsberg said. “If you grab a fence equipped with an older model, you’ll get a shock, but if you hold onto it, the charge will eventually turn into a trickle.”

Called wide impedance models, their problem was they lacked the amperage to sustain a charge for very long.

Newer models feature lower impedance. “They produce more amperage to keep the power going, to build a charge,” Remsberg said.

Older energizer wave forms show a sharp peak of voltage output. Low impedance models’ waves are longer and much wider. “The longer the shock lasts, the more the animal will respect that fence,” he said.

Energizers get their power three ways: AC/main power, batteries and solar power. AC/main power energizers are wired directly into the farm’s power lines. Battery-powered models are self-explanatory, as are those powered with solar panels.

Battery- and solar-powered models require owners to keep up on the maintenance and especially keep the grass down and limbs off the fences. “If your fence is in bad shape, it will drain more power from the energizer. The batteries and solar panels won’t be able to keep up with the power demand, which makes it into a fence with no juice.”

Buying an energizer is not easy. The industry uses a measuring unit called a joule to rate the power energizers deliver that can sometimes be misleading.

Remsberg said joules are determined using a mathematical formula that multiplies voltage times amperage times the length of the charge. The problem is that it is relatively easy to secure the first two numbers and impossible to get the charge length.

“No one will share that information,” he said.

That means joule ratings can be misleading. Two dealers may have energizers with identical joule ratings. However, one might have more voltage, have less amperage and a shorter pulse and still have an identical joule rating to a model that delivers a longer charge of fewer volts.

Remsberg said if you have bigger, more excitable animals, buy an energizer with a higher joule rating. “If your animals are easy keepers, you will need a lot less. Go bigger with sheep, though, because their wool insulates them against shocks.”

Grounding is key

The third component, the grounding system, is the most important piece, he said. He frequently encounters customers who complain that their newly purchased energizer isn’t producing the charge they expected.

Usually, he can trace the problem back to a poorly constructed grounding system. For his Pennsylvania customers, Remsberg recommends they bury at least three, 6-foot rods 10 feet apart and wire them together in a series.

Another piece of advice: Don’t mix metals. “If you use copper rods, use copper wire and copper clamps, too,” he said. Mixed metals could result in electrolysis – a white buildup that will cause the system to lose contact.

Lightning protection is also important. There are two kinds of protection: adjustable and nonadjustable diverts and chokes. Both operate in the same way. Mounted between the fence and the energizer, they divert the electricity from lightning strikes away from the fence and down into the soil.

These precautions require one extra rod to provide grounding for the choke or the diverter.

Remsberg also recommends attaching the energizer to surge protectors. “When lightning comes down those power lines, surge protectors are cheap insurance against the energizer getting fried,” he said.


Fence training

An electric fence is a psychological fence, said Kennard of Wellscroft Fence Systems LLC. Its purpose is to convince cattle or any livestock to stay away from the wire.

That’s why livestock – and predators – must be trained to respect an electric fence. “They need to learn it is there,” he said. For horses, place an apple wedge on the fence. Sheep, goats, poultry and cattle will investigate feed spread in the immediate vicinity or under electrified fences.

Swine require a special approach to training because unlike any other livestock species, they don’t jump back from an electric jolt. “When shocked, their involuntary reaction is to bolt forward and run through the fence,” Kennard said.

Construct an enclosed area with three solid sides, leaving a six-inch gap between the front and side panels. Place a single section of the wire through the gap in the front of the pen. Leave the pigs in the enclosure for about a week because, by then, all the animals will have tested the fence and experienced the consequences. Kennard added that the whole purpose of putting them in this enclosure is so there is a solid barrier behind the electric so they can run forward.

Training wildlife to stay away from enclosures requires a similar approach with different materials. “With coyotes, put some meat, like bacon, on the fence,” he said, “or leave a little tuna fish in a can, using the partially attached lid as a hook to attach it to the fence.”

Peanut butter in an aluminum foil pocket works as well. If fencing wildlife away from beehives is the goal, try smearing honey on a 35-inch tall electric net.

If deer are the problem, Kennard suggested using a scent cap, a large bottle cap containing a cotton ball soaked with apple scent. In areas where there is heavy deer pressure, attach caps every 100 feet along the fence line.

For fence meant to pen or corral cattle, a three-strand, polywire and stainless steel wire will get the job done. In rotational grazing systems, a single- to two-strand polywire will suffice to cordon off the paddocks.

Whether the operation is fencing animals in or out, a well-made fence will reinforce Robert Frost’s observation in “Mending Wall” that “Good fences make good neighbors.” They make for good livestock control, too.