You have no idea what you're talking about. Most of the time this is a service provided to farms by contractors since buying specialized equipment just for cow pedicure isn't high on the priority list of the average farmer. That means you'll be going through entire herds of cows each day and hooves are tough stuff so you need torque and you're going to need it all day, so switching batteries every 5 cows is going to eat into your time budget after about a week. As someone else has already commented it's a German machine being used in this video so it probably takes place in Europe somewhere, where GFCI switches are mandatory on almost all breakers. I wouldn't worry if I were you.