While I have had a few cows over the years try to take over my 4 wheeler, I've yet to discover one with enough sense to train to do anything other than ingest feed. I have enough trouble just getting them to stand still to milk them!
They are good at ingesting nice smelling feed and piping it through the other side to give a slightly stronger smelling substance.
Story goes that one of my father's heifers was intelligent enough to learn how to open a door with one of those gate latch "bent nail" hooks. She could get into the stall where they kept the minerals and molasses enhanced calf feed by opening the door. The calf feed was kept in an antique freezer. She learned how to push the freezer lid up.
The family rigged up a camera to find the culprit and we have a short film of her doing it all. She may have been a trainable heifer for the mower project.