A cattle farmer watching his cows grazing decided that all that mooching about is just wasted. Cows, like children, should be put to work. So he puts his cows in an energy generating treadmill set up…
“It’s not as crazy as it sounds. Cows already spend up to 8 hours a day milling around while grazing. Taylor just sticks the cows on a treadmill for part of the time. The farmer’s prototype treadmill can generate two kilowatts, or enough energy to power four milking machines. Cows that exercise are also thought to produce more milk.”
From here.