In many modern dairy facilities, cows are kept indoors year round. In the summer, ventilation systems keep the cows cool and in winter, the barn protects them from the elements. Instead of grazing, the cows are fed feed crops like grain and keeping them in one place makes it easier around milking time, this occurs two or three times every day.
New research from the USDA, however, suggests that doing the exact opposite—keeping cows outside all year—could significantly reduce the industry's impact on the environment.Using a new computer model based on field data, researchers found that by keeping cows outdoors, ammonia emissions were reduced by 30 percent. Moreover, emissions of other greenhouse gases, including methane, nitrous oxide and carbon dioxide, were eight percent lower.
There was another benefit when feed crops were converted to pasture land to support the outdoor herds. Once this was done, the sinking value of the land increased from zero to as much as 3,400 pounds of carbon per acre every year.
The total carbon footprint was found to be six percent lower than confined herds.
The research will help the USDA develop plans to support more sustainable agriculture in the future.