Researchers study growth, impact of free-range pigs

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Researchers are studying the relative merits of raising pigs on pasture and in confinement. Photo by Haley Walker

Researchers are studying the relative merits of raising pigs on pasture and in confinement. Photo by Haley Walker

LANSING — Big Blue, Gus, Chomsky, George and Leonidasto buried their snouts in leafy greens, rolled in the mud, and grunted happily when they arrived recently at Michigan State University’s student organic farm.
They had traveled from their birthplace at MSU’s old swine farm to a garden at the university’s organic farm.
It was a physical distance of only a few miles, but light years in the way the 6-month-old pigs were raised.
These animals are part of a university experiment that will look not only at their growth but also on their impact on the land.
Researchers will study flash grazing, a process of rotating the pigs for short periods on pastures to manage vegetation and aid in soil health. They will also study how the pigs grow by scavenging acorns.
These pigs are among a growing number nationwide raised as free-range, a term referring to animals that graze on pasture.
“We add farmers every day, and an increasing number of them are pork producers,” said Jo Robinson, who runs, a Web site about the grass-fed movement. “When I started in 1999, I could only find 50 pasture-based farms across the country. The fact that there are so many now is really amazing.”
Robinson’s organization lists 1,100 pasture-based farms in the U.S. and Canada, with more than 30 that raise pigs in Michigan, including ones in Mason, Saugatuck, Ravenna, Ortonville, Kalamazoo and St. Johns. Allegan, Cass and Oceana are the state’s leading swine-raising counties.
Concerns over the treatment of animals in large confinement facilities have prompted some farmers and consumers to support free-range production.
Concentrated Animal Feeding Operations, known as CAFOs, are a common type of confinement facility. To be considered a CAFO, the Environmental Protection Agency says animals must be confined for 45 days for a 12-month period and without vegetation.
Critics say CAFOs can be unsanitary, crowded and cruel and that the large amount of manure they produce in a small area is a significant source of pollution. Supporters say that CAFOs are efficient and do not pose problems if they are well-managed.
According to EPA, farm runoff is a major contribution to Great Lakes pollution and the largest contributor of pollutants to rivers and streams.
Tricia Bartholomew, co-owner of CloverDale Farms in Scotts, southeast of Kalamazoo, said the decision to run a pasture-based operation was made for the sake of both her animals and the land.
“We have recognized it is better for our pastures, and we are able to utilize their manure more efficiently this way,” Bartholomew said. “Better for the pastures means better for the cows.”
But Allen Stokes, director of environmental programs for the National Pork Board, an industry group based in Des Moines, said free-range facilities require more manure management.
“In confinement facilities, it is a more controlled process,” Stokes said. “In a pasture, you would have to make sure you rotate so you don’t get a build up of manure.”
Stokes also noted that pastures used in free-range production are more exposed to rain and snow, which increases the amount of runoff.
There is also debate about the management of gases emitted from swine confinement facilities, in comparison to free range. According to the United Nations Food and Agriculture Organization, gases from livestock, such as methane and ammonia, account for 18 percent of greenhouse gas emissions, an amount greater than the contribution from cars and other transportation.
Confinement facilities use ventilation to control the concentration of gases and use a lot of electricity, said Laurie Thorp, director of an MSU environmental education program.
“They have to cool these facilities and circulate the air, which is a good thing, but it’s energy-consumptive,” Thorp said. “What about a model where you don’t have to run fans to clear and clean the air, where they are outdoors in the fresh air?”
MSU researchers will also measure the land needed for sustainable free-range production. “It is about the appropriate number of animals for the appropriate amount of land, and the management of those animals on that land,” Thorp said.
The United Nations Food and Agriculture Organization estimates that livestock production uses 30 percent of the Earth’s entire land surface.
Stokes, of the pork industry group, said, “If you assume the same amount of animals for free range, you would need to have a larger land mass to raise the animals.
“Whether with free-range or confinement, a key would be sound management,” he said. “A well-managed confinement or free-range facility would be expected not to pose concerns for the environment.”
Haley Walker writes for Great Lakes Echo.

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