What happens when milk needs to be dumped?

Last year, a little more than 2 million gallons of milk from the region including Wisconsin and Minnesota were dumped, according to data from the Federal Milk Marketing Order. That’s enough to fill three Olympic-size swimming pools. But, the amount of milk dumped each year is small compared to total production. Last year, Wisconsin cows produced more than 3 billion gallons of milk, second only to California. So what actually happens to the milk that's dumped? It’s not just poured down the drain, explained Brian Holmes, professor emeritus of biological systems engineering at the University of Wisconsin-Madison, because milk can actually cause farmers’ wastewater systems to fail."The fats would float to the surface and that creates that cake," he said. "A drain field relies on infiltrating the water into the soil, and all those milk proteins and sugars and some of that fats will seal up the soil so that the liquid can't drain into the soil." Often the best thing to do is to load the milk onto a manure spreader and spread it over a farm field. Holmes said it’s still important to be careful not to apply too much too quickly."You might have a runoff situation," he said. "And if it runs off and gets into a stream, then you'd be in trouble with contaminating a stream."