The Swedish agricultural university SLU is researching the virtual fencing of livestock. In the project, the animals are taught to obey the signals given by a collar when they approach the invisible gps fence of the pasture, which the farmer has determined with his mobilephone. The collar first gives a sound signal, and then a small electric shock if the animal does not turn back. The technology is not alloweyd yet in Sweden, but it has attracted a lot of interest and research continues.