Googling the term, you get pictures of mixer-feeder wagons, which are filled with silage, hay, concentrate, or whatever else is in a dairy cattle ration. In the bottom of the wagon is a powerful auger that mixes the ingredients, and then you drive the wagon along and empty it into a long trough for the cows to eat. They also show pictures of tractor (front-end loader) mounted equipment for cutting silage loose from the pile (in bunker-type silos), not sure exactly which would fit but hope I've given you some idea.