Before the onset of steam, petrol and diesel, transport, whether equine or bovine based ran on hay.  In those days owning hay meadows was as good as having your own little oilfield.  Just think of the vast amounts of the stuff that had to be carted into cities to power all those posh carriages, cabs, horse-buses, carriers' carts and "honey wagons",

Stubs Haycart
Another Stubbs from the Liverpool Museum Gallery.