A recent study by UC Davis examined the amount of land required to grow feed for California dairy cows. Through increased crop production and the utilization of agricultural byproducts, the amount of land required to produce a gallon of milk was reduced by 89 percent from 1964 to 2014. Improvements in crop genetics and production practices have dramatically increased crop yields.
Dramatically improved feed crop production and utilization of agricultural byproducts, such as almond hulls and citrus pulp, as feed have led to significant reductions in the amount of natural resources used to produce each unit of milk, including land, water, fossil fuels, and energy.