In the state of Iowa, there are about 1,360 licensed dairy herds. Iowa is the 12th largest milk-producing state in the U.S. Iowa dairy farms produced approximately 562 million gallons of milk in 2015. Iowa farms generate approximately $837 million in milk sales annually. In Iowa, the average dairy cow produces about 7 gallons of milk per day. That’s more than 2,667 gallons of milk over the course of a typical year. Iowa has 14 plants that process one or more dairy products. It takes about 48 hours for milk to travel from the farm to the dairy case.