The impact of electric shocks on animal welfare in the long-term depends on how fast the animal learns how to avoid it, and to what extent the animal experiences having control of the situation.
This is the key message in a literature review conducted by the Scientific Committee for Food and Environment (VKM) on behalf of the Norwegian Food Safety Authority.
There is no general rule regarding the use of electric equipment on animals in Norway. Outdoor electric fences are legal and common. Use of certain types of equipment or devices that subject animals to electric shocks are either banned or regulated.
The intention of using such equipment may be to keep the animal within a specified area, for example with electric fences, suppressing certain behaviours or teaching the animal a specific behaviour. In order to achieve a desired effect, the animal needs to associate the aversion of receiving a shock with its own behaviour, and learn how to change behaviour to avoid new shocks.
The Norwegian Scientific Committee for Food and Environment (VKM) has summarized knowledge on how animal welfare is affected by equipment that is commonly used at present. This includes, for example, outdoor electric fences, virtual fences, various types of electric collars, electric cow trainers to keep the stall and animal clean, and electric goads to drive animals forwards in slaughter plants.
After reviewing the literature, VKM found that electric fences have few disadvantages, since these are visible to the animals and they can thus easily avoid it. Such a situation is both predictable and controllable, and the animal quickly learns to keep its distance to the fence.
- Virtual fences do not have visible boundaries. In this system, an alarming sound is emitted from a collar worn by the animal, alerting it of the boundary. The prerequisite for this system to work, is that the animal understands that the alarming sound entails an impending shock if it proceeds moving forward. Some species and individuals learn more quickly than others how to react to avoid a shock. Studies have shown that cattle and goats can learn this system, says Cecilie Mejdell, spokesperson from the working group of this opinion.
VKM highlights that electric equipment that is attached to the animal for longer periods of time represents a hazard, which in worst cases can result in technical malfunctions with sustained shock delivery. Skin irritations may occur if the collar is heavy or fitted tightly around the neck
- Since electric shocks are unpleasant, the animal may associate the stimulus with whatever it was preoccupied with. This could result in the animal making other associations than what was intended, which can be difficult to eradicate afterwards. Dogs that have gone through obedience training with electric collars may become passive, often showing signs of anxiety or aggression. The animal may also become more cautious in order to avoid shock. Cows standing in tie stalls, with electric cow-trainers mounted above the back, spend more time laying down or getting up, than cows without this device, says Mejdell.
Devices with other types of punishment, such as anti-barking collars with citronella spray, may be just as effective. Use of such devices probably has less impact on animal welfare.
Scientific data on how electric equipment affects animal welfare is scarce, especially in a long-term perspective.
- Research appears to focus more on functionality of electric equipment than on the consequences for animal welfare. Knowledge on the number of electrical shocks that is necessary for the animal to learn how to avoid it is largely lacking, says Mejdell.
The VKM panel on animal health and animal welfare is responsible for this report.