Electric fencing started to appear in the newspapers in the 1930s.
Along with safety, animal welfare, barbed wire, and demonstrations — it was all happening when these electric fences started to beused by progressive farmers.
Its ingenuity lies in the fact that only when the wire is touched does the current flow along it, and the shock received by the animal, although harmless, is sufficient to discourage it from trying to get through the fence.
A small herd of cows was driven on to a square of paddock surrounded with a single length of barbed wire attached to the electric controller.
Hay was distributed along the outside of the wire, but after one or two attempts to circumvert the wire the cows ignored the hay and cropped the grass in the enclosure.
Pigs and sheep, tested with a 2-wire system, quickly learned not to attempt to escape from the enclosure.
The inventor claims that a single battery will operate one of these units along 10 miles of fencing for three months.
An animal may rub lightly against a plain wire and get little or no shock if its hair is dry; in the case of barbed wire the barbs get in through the hair and the shock is more intense.
The current passes through the wire intermittently; there is no discharge of the battery until something comes in contact with the wire.
The strength of the current varies according to soil conditions and the size of the animal.
A large animal such as a horse or a cow is more sensitive to shock than a smaller animal.
Mr. Donnelly explained why animals are subjected to a greater shock than human beings.
The pigs also displayed their behaviour towards this modern fencing idea and held a deep respect for their scant enclosure.
It was found that they could not be driven or coaxed with food through the wire.
It was felt that the Young Farmers’ Club had learned something new upon which to form their future fencing ideas.
An advertisement for electric fencing in the Gisborne Herald, September 18, 1940. Image / Papers Past
In the House to-day, Mr. W. J. Broadfoot (Opp., Waitomo), in an urgent question to the Minister of Customs, asked if he would see that the permits were issued to allow 14-gauge two-strand barbed wire to be imported to enable adequate supplies for electric fencing to be available for the farming community.
The Hon W. Nash replying, said that barbed wire was manufactured locally, but when supplies were inadequate the necessary permission was granted for importation if it were available overseas.
The question of electric fencing was under consideration, and if it proved practicable and satisfactory farmers would receive all the assistance possible in this direction.