New Research from South DakotaStateUniversity disputes popular press articles that say the environmental impact of agriculture is on the rise.

In 1924, there were 21.42 million dairy cows in the U.S. — 12.27 million more cows than today. A cow in 1924 produced an average of 4,162 pounds of milk per year compared to an average of 20,231 pounds in 2007.

“If you look at the ratio of methane to milk production, three times more methane was produced per pound of milk in 1924 compared to today,” says Alvaro Garcia, extension dairy specialist at South DakotaStateUniversity. As a result, methane production is 40 percent less today.