Modern dairy farming began in the early 1900s after pasteurization was developed and practiced. Pasteurization allows for a safer product and extends milk's shelf life by eradicating spoilage-causing bacteria through the application of heat. This process allows milk to last longer and be shipped further. With easier access to safe milk, demand increased as did the need for larger farms. These larger farms rely on healthy cows and efficient practices to produce larger amounts of milk and dairy products. While these farms have grown and become more efficient, farmers still focus on reducing environmental impact, producing safe products and keeping their herds healthy and content.