TOWN OF PICKETT, Wis. (WHBL) - Fire did roughly 1 million dollars damage to Wisconsin’s largest dairy farm yesterday afternoon.  The blaze broke out yesterday afternoon at Rosendale Dairy on County Trunk M in the town of Pickett, near the Winnebago-Fond Du Lac County line.  No cows were killed, and the fire was confined to a building where grain feed was stored.  Authorities say sparks from a tractor pulling into the building may have started the blaze.  Rosendale Dairy has 8,000 cows and is owned by Milk Source in Kaukauna.