Currents

In order to stun or kill an animal with electricity, it is necessary to pass sufficient current through the brain, or through the brain and heart respectively. Therefore, accurate electrode placement is of paramount importance. However, assuming correct electrode positioning, it is the magnitude of the current that determines whether the animal is stunned or killed. Table 4 shows the recommended currents, for head-only stunning and head-to-body killing, delivered by a conventional 50Hz sine wave supply voltage.

Table 4 Recommended currents for stunning and killing animals

 

 Species

Current

Stun
(Head-only)

Kill
(Applied to heart)

Cattle

1.28 A

> 1.51 A

Calves

1.25 A

1.25 A

Sheep/Goats

1.0 A

1.0 A

Lambs/Kids

1.0 A

1.0 A

Pigs

1.3 A

1.3 A

When applied correctly, with electrodes positioned to span the brain, these currents will stun immediately. Within a normal working environment it is recommended that the current should be applied for at least three seconds. If electrocution is being carried out, the frequency of the current should be no greater than 100Hz because, as frequency increases, ventricular fibrillation is less likely to result.

Most modern stunning equipment operates at outputs in excess of 200V, but some automatic equipment, where there is less risk of the operator coming into contact with the electrodes, can run at up to 1000V. 

Note: Older electrical stunning systems, with outputs of 150V or less, are not considered to be effective at producing an immediate stun. The HSA recommends that such equipment should be immediately taken out of service and replaced with modern, higher voltage stunning systems with outputs of 200V or more.

 

Next: Resistance

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