Video Link : http://www.facebook.com/FarmvilleSharing
Get a lot of coins with harvesting your Dairy Farm :
Empty your Dairy farm, have cows on your farm that are ready to harvest, have at least 1 belted cow in your Dairy farm
(the more belted cows, the more coins you get) Put a ready cow in the Dairy Farm with the Move tool, and harvest your Dairy farm.
Put another ready cow in it, and harvest it again. Each time you harvest you will get coins (With 1 belted cow in it you'll get at least 3000 coins
