THE ELECTRIC FENCE

Cattle if left to themselves will spoil much of the grass on offer, as they will just walk about picking the best and contaminating the rest with dung & urine.

In order therefore to better manage the available grassland we use an electrified fence to restrict access and give them some fresh grass twice a day.

Here at Greenheyes the fence is a mains powered system. Some run off there own generators and some are battery powered. On some farms you may find a combination of the different types, with one acting as a back up for the other.

Being supplied from the mains, ours logically starts at the farm buildings and has approximately 2 miles (3 kilometres) of wire in the system. (On some large farms the total amount of wire in fences be in the tens of miles).

The central fence runs along the side of the cattle drive up and along the top of the middle & heifer banks to the boundary hedge on the heifer meadow. Along this route there are take off points (shown on the right) for the more temporary fences.

This picture shows a part of the "Spring Gate" we use to divert the cows into the paddocks. It is basically a large spring which when hooked across the drive into the fence becomes "live". In the picture it is hooked onto a power "take off" point.

The handle being a plastic is insulated from the current. That said care should always be taken when connecting and disconnecting (opening and closing) the gate.

We use 2 types of grazing system on Greenheyes, Strip and Paddock. Strip is where the fence is moved (usually daily) to give the cows a fresh strip of grass.

The strip fences use these light metal posts with 1.5mm wire.

They are simply trodden into the ground to fasten them and are designed to be moved (as at Greenheyes) every day.

On the key field we employ a paddock system where the field is split into 4 0.75ha paddocks and the cows spend 2-3 days on each.

The fences of the paddocks are made of wooden posts onto which are attached electrical insulators that hold the wire of the electric fence.

 

We prefer the paddock system as it means that the grass can be given fertilizer and will recover quicker than the strip system, which cannot be fertilized until the whole field is finished. These systems also help us to make best use of the grass in the spring and help us to save more for silage making.

For the technically minded the fence is rated at 5,000Volts (V). The normal voltage carried is 4,800V. The second part of the equation is the current or Amperage. Unlike the high Voltage, this is only a few (about 2-3) milliamps.

The Voltage serves as the driving force to overcome the resistance of the wire and carry the Amps around the circuit. Despite the high voltage, the fact that the current is only a few milliamps means that should you accidentally come into contact with the fence you should only feel an uncomfortable sharp shock.

Now A few words of caution

You notice that I have emphasized the should! Electricity is a dangerous form of energy and can easily kill given the right circumstances.

While the fences at Greenheyes and the electrical equipment that provides the power for them are regulary serviced and well maintained, it is always possible that, despite all the precautions we and others take, the fence may for some reason malfunction.

Because of this, whenever and wherever you come across an electrified fence, or a fence you suspect to be electrified (Any electrified fence to which members of the public may have access should be clearly marked as such)

ALWAYS ASSUME THAT IT IS "LIVE" (switched on)
and
DO NOT TOUCH!!!

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