The investigation is underway to try to determine the cause of a massive fire that destroyed a barn and attached pole shed in Eldorado. Ten dairy cows perished in the fire. Firefighters from 15 area departments were called to the Laura and Greg Rickland farm on Lincoln Road in the town of Eldorado at about 3:30am Friday. The 18 thousand square foot structure was destroyed. Fond du Lac County Sheriff’s captain Ryan Waldschmidt says a sheriff’s detective is working with Eldorado firefighters to try to determine a cause. No people were injured in the fire. Damage is estimated at $250,000.