Cows Want to Be Outside as Much as They Want Food

The majority of dairy cows in the United States don't spent time in pasture, which new research suggests they highly desire access to. Russell Cheyne/REUTERS

How ardently do cows love going out to pasture? Quite a lot, it seems. As detailed in a recent paper in Scientific Reports , researchers came up with a scheme to measure how driven cows were to either access food or go out to pasture. The team, led by Marina von Keyserlingk and Daniel Weary at the University of British Columbia, steadily increased the amount of force it took for a cow to open a door that led to food or pasture.

The majority of the cows pushed equally hard to get to food or to get outdoors. They noted that the cows were much more interested in going outside at night, and once outside, many of them lay on the ground to sleep. (Von Keyserlingk says it may be uncomfortably hot during the day—the study was conducted in the summer—and that the cows prefer to stay inside, where it is cooler in the daytime.)

Fewer than 5 percent of cows in the United States spend a majority of their time in pasture, and "80 percent never see a blade of grass," von Keyserlingk says.

Surveys of dairy farmers suggest that many would like to let their cows out to pasture, but worry that it would reduce the amount of milk they produce, Weary says. However, work done by the group shows that animals who spend the night outside produce the same amount of milk. Thus, letting Holsteins out in the evening is any easy way to improve the well-being of cows without sacrificing milk production.

James Drackley, a professor of animal sciences at the University of Illinois who wasn't involved in the research, notes that this research doesn't tell us anything about the welfare of cows who don't get to go outside. There are many valid reasons for keeping cows indoors, he says—for example being outside exposes them to inclement weather and predators.

It's unclear exactly why cows desire to be outside, but one specific reason they seem to enjoy it is that grass is softer than the floors of indoor pens, which are often made of concrete. Pasture also allows them to move more freely and exercise. Past research by the team shows that cows let outside don't eat less than "insiders," suggesting that eating grass isn't a prime motivator, at least for one group of Canadian cows.

People for the Ethical Treatment of Animals opposes dairy farming on the basis that it mistreats cows, and in a 2009 report, the Humane Society argued that "providing regular access to pasture and suitable high-fiber diets could help alleviate the health, stress, and behavioral problems associated with confinement."