Winds Of Change: Data-driven Model Directs Location Of Swine Barns

Drawing concentric circles around swine barns never made sense to Steve Hoff.

That’s what he saw in source-based swine odor models. Like a pebble dropped in a pond, the models seemed to say the more ripples you put between a proposed facility and neighbors, the better.

That’s backwards, says Hoff, a professor of agricultural and biosystems engineering. “What’s real are those living nearby who may be on the receiving end of odors.”

That’s where he focused his research, which led to development of a revolutionary receptor-based model called the Community Assessment Model, or CAM.

Since 2005, CAM has been a valuable preplanning tool offering guidance for hundreds of Iowa pork producers on where to build new facilities.

“Steve’s model uniquely anticipated where a potential odor problem would be,” says Jay Harmon, a professor of agricultural and biosystems engineering and extension agricultural engineer. Hoff and Harmon care for and maintain CAM.

Hoff fed the model with years of ISU research data, including emissions; down- wind odor concentrations; and historical weather and atmospheric patterns. CAM notes location of neighbors, other odor sources, number and age of animals, seasonal ventilation rates and more.

Instead of concentric circles, CAM produces shifting oblong or jagged shapes that illustrate where odor may move, depending on predominant weather and the seasons. The model estimates what percentage of time a neighbor may be exposed and factors in how odor-reduction technologies would benefit sites.

CAM is intentionally voluntary and conservative, Hoff says. “It errs on the side of caution. We want a farmer to start out on the right foot by considering his neighbors.”

If Hoff and Harmon are the brains behind CAM, then its face is represented by Colin Johnson of ISU’s Iowa Pork Industry Center and Kent Mowrer of
the Coalition to Support Iowa’s Farmers.

For more than eight years, ISU and the coalition have partnered to advise farmers on selecting sites. The coalition’s mission is to help farmers raise livestock responsibly and successfully.

Mowrer, a field specialist, makes initial contacts, answering farmers’ questions and determining if a situation would benefit from running CAM.

Johnson, an extension program specialist, brings to the table extension resources on environmental, economic and community stewardship. “I stress that growth needs to be environmentally, socially and economically sustainable,” he says.

Mowrer says that although CAM may not be run for every site, its there in spirit. “Each time we go to a farm we’re using ISU’s science that went into CAM. CAM really helps explain the importance of putting new barns where they’ll have the least impact.”

Recently, Mowrer says about two-thirds of the calls fielded by the coalition have been from young people. A new hog barn is a step that makes economic sense to sons or daughters who want to farm.

“Many of these young people will be tomorrow’s leaders who’ll invest in their communities and schools,” Johnson says. “That’s a win-win for everyone.”