The study compared feeding dairy cows different types of food while they were out in the pasture. In one experiment, they gave the cows lucerne, hay, or concentrate along with grazing. In another experiment, they replaced hay with silage. The cows were fed supplements for 1 hour after each milking session. The researchers wanted to see how these different diets affected the cows' milk production and health. They found that offering supplements like lucerne, hay, or concentrate to grazing cows can impact their milk production and overall well-being.