The virtual fence (VF) is a newer system for fencing pastures for animals without the use of a fixed fence. The aim of thesis was to investigate the functioning of the VF and its effect on animal welfare. The VF system uses a GPS collar with devices for acoustic stimuli (AS) and electrical stimuli (ES), which each animal must wear, and a virtual fence, the location of which is determined by the breeder using an app to control and monitor the system. When the animal crosses the VF, a low voltage ES is triggered on the collar, which is uncomfortable and stressful for the animal. As the location of the VF changes, the animal must constantly learn where the invisible fence is located. To minimize the number of ESs the animal receives, a AS is triggered at a certain distance from the VF to warn the animal that it is approaching the area of the unpleasant ES. Within a week, the animals learn that the AS signals the ES and what they need to do to avoid the ES. Consequently, after the first week of acclimatization to the VF system the number of ESs decreases significantly, while the number of ASs remains quite high. After moving to a new paddock, the number of ESs does not increase significantly, but the number of ASs increases in the first week in the new paddock. Low voltage ESs do not cause the animals any more stress than regular breeding tasks such as weighing or immobilizing the head in a crush. Monitoring of stress indicators (e.g. cortisol, β-endorphin, haptoglobin and ceruloplasmin concentrations, heart rate, feed consumption, milk production, body weight) confirmed that VF has no prolonged negative effects on the animals and their welfare.
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