Reading down the rant and moan entries I came across the ones on dog mess. Reminded me of the time my husband got so annoyed with a neighbour who, despite being asked to stop, insisted on letting her afghan hounds foul our small gateway every day. Fortunately for us we had a small gap in the hedge further up, that the kids going to school could brush through. Wasn't perfect though.
So one day he collected that day's mess in a carrier bag and next morning very early, went up dropped it all over their front step. They got the message.
Woody - Not sure it would work on farmer with cows though.