Electric Fencing and Carnivore Damage Prevention

Dr. Tone Vidrih,
Chair of fodder production and pasture management, Agronomy department, Biotehnical faculty
Jamnikarjeva 101, 1000 Ljubljana, Slovenia

Electric fencing is a well accepted method of controlling domesticated stock. Compared with other methods of controlling animals, electric fencing is fairly simple but there is no magic about it. Electric fence presents almost no physical barrier, but instead relies almost entirely on the fact that the animal gets shocked whenever it touches the fence. Great part of information needed for to make good electric fence, well grounded energizer or how to protect it from the lightning, can be found in booklets and leaflets published by the manufacturers of energizers and other material for electric fence. The goal of this writing is to point out some remarks, that can help to achieve better protection of livestock against predators with electric fence.

Don't shoot – shock

In recent years many have found electric fencing a highly efficient and low cost method to stop the conflicts between wildlife and man. Both of this two kind want to have more space to breed in peace, be watered and fed properly. Large carnivore can survive in the long term on freedom throughout natural habitats of Europe only if they get strong enough fear to people and their property (livestock).The fear is the most natural and only efficient method that enables different kind of carnivore to live in coexistence with each other and with the man. We can scare predators with shooting, fire or pain of electric shock. It is better to shock them than shoot, and this is for the benefit of both, the man and the beast!

Some people advocate that punishment to animals is to be avoided on welfare ground. Nature does not listen to such talk. When a child puts its hand on something hot (stove in the kitchen), it is immediately punished and avoids the hot item after one trial learning. In fact, many of the learning events in the nature world operate around punishment, especially between predators. Animals learn by trial and error, only if it is punished does it learn to leave certain "bad" things alone.

Livestock fence

With livestock fences we have aim to turn animals about 95% of the time, in most cases this is sufficient for the grazing management need. Because the fence is psychological, rather than physical barrier, the animal must be trained to the electric fence before control is attained. Without such training, the fence will leak the animals and there will be some fence repair to do every day. However, if every time the animal touches the fence it gets shocked, it won't take long before they learn to have a healthy respect for the electric fence. Learning and training are closely related; the animal must learn if it is to be trained.

However, training does not produce new ways of responding to situation; the animal can't be trained to do things that is not capable of doing. All training can do is to reinforce some desirable behaviour that the animal already is capable of doing. Livestock are easy to train to electric fences, because they are calm, they have grow up with electric fencing, have enough feed and water on pasture, they stay on same paddock few days, and learn electric fence during the day time as a group. They have no reasons to attempt to penetrate the fence. But it is still most important that electric fence is always ON when the livestock are in.

Carnivore damage prevention (CDP) fence

With the predators is quite a different situation. They can penetrate the fence by accidental wandering if the fence lays on traditional migration routes. In the search for food they have to overcome different obstacles and most difficult is fear of humans. Even very painful shock from electric fence is not too big problem for a mother following young, hungry wounded or old predator, to crawl or jump through the fence. There is still very few electric fences designed for predator control on whole year basis, and this way not much opportunity for large carnivore to learn to respect electric fence. Even livestock fences are switched OFF during out of grazing season time, when migration of predators can be very frequent.

Basic rules

Despite to a number of essential differences between conventional electric fencing for controlling livestock and electric fencing for CDP needs there are some basic rules when building the electric fence. The visibility, the design, the high power, the training, and the maintenance are these rules that have to be obeyed doubly to make effective electric fence for the need of carnivore damage prevention.

Visibility

The first and most obvious one is that the fence must be visible. All the carnivores which we wish to control, are most active at dawn and dusk when light levels may be affecting the colours they see. Most contacts of electric fence occur at night. The fence will not control a large animal which runs through the fence without even seeing it. Better visibility of electric fence can be accomplished by using lots of wire and post, or tying things on the wire that flutter in the wind, such aluminium twisters or spinners. Light (to move in a breeze) reflective material is best. The wire should be at least 2.5 mm tick. Thiner wire reduces the visibility, conductivity and life of the fence.

The fence line must be well cleared from the side of predators approach to stop and to get them to investigate the fence in a slow and cautious manner. Maintaining the fence visibility is part of the maintenance work. Good visibility of permanent wire in electric fence is achieved if the white electric tape (polytape) is mounted on offset brackets on the fence from the predator approaching side. Such a polytape can be set on the top of the fence to increase its height.

Design

Before we can possibly hope to control large carnivore with electric fence, we must first know something about the animal we are attempting to control. As first we need to know how the animal intends to penetrate a fence. Consequently there is no one fence design that is going to work for all species of animal, under all condition, for all time. In designing fences for CDP, finding what works and does not work is not so much using available theory as it is trial and error. Each animal has different behavioural pattern, that should be considered. The fence must be designed for the animal that is to be controlled. Fences design and training should aim at the animal receiving shocks through the head. These are much more sever than through other parts of the body. The longer the distance the shock travels through the body, the greater effect it has.

There is a need for a precise knowledge of the species specific behaviour of the animal for which the fence are being designed and as well, the behaviour of other species which use the same habitat. Especially the prey of that predator, must be taken in account. Therefore some fences for the control specific carnivore must in fact be designed to cope with several wildlife species. Wild animals are a bit above domestic livestock when it comes to ingenuity and finding new and novel ways to test the fence. The fence is tested continuously, if not by the same animal, then by new ones moving into area. It cannot be assumed that all or even most animals will be preconditioned to the fence in short time.

Crawlers

Fence for CDP must have at least six wires. The wires should be alternating in charge (-,+,-,+,-,+, etc.). The bottom wire is best to be ground (earth return wire), 10 cm above ground. The low wire causes those animals that like to go under the fence as their first or second choice, to go over the ground wire, so when it touches the live wire, good electric contact is made. Snow and frozen ground in winter can greatly reduce the effectiveness of electric fence for predator control if the fence has not an earth return system. If the electric fence is not in use during the winter time, than the all lines should be put on the ground to be covered by the snow. This way predators will not learn to crawl through the not defended fence. The fence line must be set up again early enough, before the stock arrive to the pasture, to let the predators know, that is the end of free wandering over particular territory.

Jumpers

Predators that jump over the electric fence learned this on mesh wire fence (sheep fence) or similar kind. Jumpers are a slightly different problem. There are two approaches, the first is using a visual barrier fence in front of the main one. This in effect widens the fence so that the jumper must not only clear the height, but also has to go for distance. The second approach is to lean (tip) the fence towards the direction of animal approach. Angle or leaning fences definitely give better predators control than vertical ones. They seem to deter the animals from jumping over and from pushing through. Having the angle leaning towards the animals to be controlled aims at having the animal come up and hopefully lift its head onto fence. Despite the advantages of angle fence, vertical ones are recommended to be used wherever possible because of their easier construction and maintenance.

Offset brackets

Offset wires can be used to achieve the same benefits of the angle fence without the associated construction, and in some cases, maintenance problems. One or more offset wires, on the side from which the predator will approach, adds to the penetrating control ability of electric fence tremendously. Fence maintenance is also reduced if the properly designed, galvanised spring steel wire offset brackets are used. These are easily twisted onto existing fences and are flexible so withstand animal pressure. One or more offset wires can be placed on fences, but where only one is used, it should be positioned at a height of 2/3 rd that of the predator.

For large carnivore, because of the tick fur and its insulating properties, wire tension must be increased and maintained at 180 kg, especially on bottom wires. Permanent tension spring can be built in each line or wire tension must be checked more frequently. Because of this the fence can be more flexible. Best use should be made of both the vertical and horizontal flexibility allowed by electric fence.

Bears are relatively easily blocked with on the fence. They will try to crawl over or through the fence, and because of big feet they have a good contact with the ground. Offset wire keeps them well away from the main fence if they get only angry, and not scared, because of to weak electric shock. Wolf can penetrate a fence by digging under where bottom wire is higher than it should be. Similar way the fox will penetrate the fence. An uneven fence line may permit them to go under the wire. So it is extremely important to level the fence line properly, and reseed with the grass, and keep the grass green. Lynx jumps over the top of the fence if there are higher objects near the fence. If there are tick corner post in the fence lynx can jump on its top and further on protected area. Out goes the same way. Because of this is require more complex fence to retard him. All the trees, shrubs and debris must be cleared from the fence line. This must be wide enough to prevent trees from falling on the fence, for better visibility of the fence and their easier maintenance.

High power

Operational efficiency must be high for electric fencing to repel large carnivore penetration. If a fence lacks operational efficiency then animals will soon overcome their “ fear of the fence” and it may take several weeks of training to re-block them. Good operational efficiency is only obtained if the fence is capable of giving all intruding large carnivores a shock whenever the fence is pressured. Unlike domestic stock, one cannot rely on that all migrating large carnivores become trained to respect electric fences. Large carnivore can break through electric fence unless very high powered energiser (Smart Power) is used. The high power must be all the way the electric fence is extending. Any fence is only as good as its farthest part of it.

Trials with all type of animals, domestic and wild, have shown that a low powered shock causes the animal to come back for more which means that they are repeatedly testing the fence. Some animals have been known to become accustomed to a low powered shock and thereafter to ignore it, with disastrous results. At least 4.500 volts should be maintained on all wildlife fences at all times with pulses at as close to one per second as possible. It is better to enquire from successful users rather than go through the trouble and expense of investigating a new fence with the possibility of failure.

When building a new fence to control migration of animals, we must make sure the newly constructed fence is turned ON before securing for the night. First impression is important. The first contact must be a memorable event. One basic rule that is overlooked more often than not; the fence must be effective when the predators are. In other words if the predators operate at night, it does little good to check the fence out during the day. Check it out at night, when dew or other night things may be causing shorts.

Be aware that electric fencing systems invariably grow over the years to meet changing conditions or circumstances. The new generation technology is the one that makes power fencing much simple, more efficient and more reliable. Easy to work and live with. Features for managing smart and high power fence system include:

- Remote control to switch the energiser on/off from anywhere on the fence where there is a need for the maintenance work on the fence.

- Performance indicator lights or digital displays

- Monitors and alarms to warn of poor system performance

- Adapted control that automatically adjust output to suit fence conditions.

- Have a replaceable modules for easy servicing

- Built-in lightning protection to help protect the energizer from extreme damage.

Energizer selection is determined either by size of area to be fenced or the length of the fence. Both are just estimates, and only when you connect energizer to the fence will see (feel) its capability.

Maintenance

Electric fences are not maintenance free. This must have everybody in mind when buying the material for the fence. Each separate component should last for the expected life of the entire fence. In other words, it should all fall apart at the same time. The differences in cost between the most expensive item and the cheapest, does not affect the total cost of the fence all that much. By using inferior materials for electric fence the CDP will not be effective for very long time. Once the fence is erected, continual maintenance is a must. The fence must be visually checked on a periodic basis, in addition to the regular electric checks with a voltmeter or control light (live light) hanging on fence, which tells you in a flash if your power fence is operating. A yearly check of the earth system of the energiser is also required. Maintaining the fence visibility is part of the maintenance and animal training programme.

The first requirement is to gain as much knowledge as possible of all the species against which the fence is to be effective, remembering that one or more of these species may be able to breach the fence by accident. The range in size of the species, including the young which may travel with the adults or even ahead of them must be considered. More knowledge on the sensory capacities of animals would allow a fence to be designed at least cost with minimum time wasted in trial and error attempts at animal control. As well, the normal flight responses, patterns of tracking investigation or neophobic traits as well as the physical dimension of the animals must be considered.

Training

All animals, domestic and wild, can be trained to respect an electric fence; however, all require time and space to quietly discover the major dissadvantage of fussing with an electric fence on their own. The most difficult period for animal control will be the initial period after animals have been excluded from territory. The whole idea of predators training is to get them to investigate the fence in a slow and cautious manner, so if at all possible, that all important first shock is delivered to the nose. If the shock is delivered to the back of the head the tendency is often to go forward rather than back up.

There are several ways to help predator to raise nose on the fence. The first one is that the fence must be visible. The bait (chicken wing) can be hang up on the live wire in the fence. There is not need that predator grabs for the bait, it is enough to put the nose close enough to it. The next generation of predators will learn the trails and behaviour response patterns of their elders. Early control measures will be the most difficult ones while later control problems for wild animals should not be so formidable. The strength of the first shock will often determine how the animal is going to react to the fence in the future.

Conclusion

If we want to develop sustainable farming practice (better soil fertility, higher biodiversity, clean water and air, less pollution in atmosphere) than we need the herbivorous to help us to reach this goal. But this can be achieved only if we can protect domestic animals effectively from large carnivore. To put one or more electrified wires in the path of the animal is not sufficient. With my 20 years of experiences building of smooth wire electric fence for controlling livestock, I have seen just about every fencing mistake possible. But those fences were put there just to keep domesticated animals on place. Those fences are not expected to be 100% effective. Livestock fences aim to turn animals about 95% of the time, in most cases this is sufficient for the grazing management need. With electric fence for the need of CDP most of these mistakes would be the case for low protection efficiency.

The knowledge and experiences obtained with building livestock fences are not enough to make a good fence for a need of CDP. If there is any danger from predators in the area, we probably cannot count on a seasonal pattern for protection. Predators will hunt down livestock whenever their regular food supply is short. They will be back until the fences are secure enough to keep them out. No fencing system containing barb wire should ever be electrified and used for CDP need. Permanent electric fencing costs so little and is so easy to construct that we should take enough time and material of good quality to do the job well. Otherwise there will be many reasons that the fence will not serve to its purpose. Our ability to think and develop the new idea, that will work for the carnivore damage protection, is the only limitation that the electric fence has.

We should have in mind all the times the differences between livestock and wild animals. And on the top of this even I still make mistake myself when building a new fence, because I am constantly challenging myself to make fencing easier and faster.

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