Dairy Cows’ Carbon Footprints from Barn to Field
Greenhouse gases, which collect in the atmosphere and trap the sun’s radiation, are a big issue for the dairy industry. Methane is a concern because it’s particularly potent — it traps about 30 times as much radiation as carbon dioxide. A dairy cow generates a lot of methane in her rumen, the huge stomach chamber where microbes ferment as much as 200 pounds of plant material. Also worrisome is nitrous oxide, another potent greenhouse gas that manure releases during storage and after it’s spread in the field.
Michel Wattiaux, a University of Wisconsin–Madison researcher, began using a specialized device to measure the methane being exhaled or belched by a group of Holsteins and Jerseys. It was the first step in an ongoing study by dairy scientists, engineers, and agronomists to see how a cow’s breed and forage consumption affect the greenhouse gases generated by her gut and her manure.
Wattiaux said this is the first time where the nutrition, manure storage, and field application parts are conducted sequentially. Data is then put together to give the Wisconsin dairy industry a solid number for how much methane and nitrous oxide comes out of their farms, depending on the breed, diet, and amount of forage in the diet.
This work was funded by a NIFA Hatch grant and through the Agriculture and Food Research Initiative.
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