The world-famous primatologist discusses her new book, which is back on shelves after some controversy.
Hog farmers in the Midwest are on edge about an unusual problem: foam sometimes forms on the manure piles, and apparently causes flash fires and explosions.
Scientists are trying to figure out the cause.
From the Here & Now Contributors Network, Amy Mayer of Harvest Public Media reports.
JEREMY HOBSON, HOST:
From NPR and WBUR Boston, I'm Jeremy Hobson. It's HERE AND NOW.
As the farm bill debate resumes this week in Washington, hog farmers across the country are getting ready to pump a year's worth of manure out of the pits under their barns. The nutrient-rich slurry will help fertilize crops. But a year's worth of manure has its downsides, including a mysterious foam that sometimes forms on it and can cause explosions. From the HERE AND NOW Contributors Network, Amy Mayer of Harvest Public Media reports from Ames, Iowa.
AMY MAYER, BYLINE: Howard Hill stops his red Chevy pick-up truck beside a barn near Union, Iowa that houses 1,000 of his hogs. In the truck's bed is a 55-pound bag of Rumensin 90. That's a common antibacterial ingredient in cattle feed that helps reduce bloating. Pigs don't eat it. Hill has brought it here to dump into the manure pit under the hogs.
Outside the barn, Hill and Kent Reinert, the manager here, remove a fan to access to the eight-foot-deep pit. It extends under the barn's slatted floor, capturing a lot of pig poop. The men peer down at a gurgling brown mass.
HOWARD HILL: That gas bubbling in there turns the whole thing kind of into - it's been described as a milkshake.
MAYER: Certainly not an appetizing one.
HILL: Whereas typically, you know, in a pit you will have the heavy material down at the bottom. And that's why we agitate. And in some cases we haven't even had to agitate these pits because it's homogenous already just from the bubbling process.
MAYER: Hill has brought the bag of powder to calm the gaseous mass. This is his first time dealing with foam, a vexing problem that's become a persistent issue in the upper Midwest since 2008. Several flash fires have killed hogs and injured workers. In one barn, 1,500 hogs perished. And still, scientists haven't found the cause. Iowa State University professor Steven Hoff is leading a million dollar, three-state research project.
STEVEN HOFF: What we're finding is that roughly 25 percent of the producers that we're surveying are experiencing some form of foaming.
MAYER: Those farmers are in Michigan, Illinois, Minnesota, Iowa, Nebraska and Missouri. And many have reported the cattle feed ingredient has quelled the foam. While they don't know what causes the problem, some believe extremely hot weather contributes. Hoff says that's one of many possibilities.
HOFF: We're looking very extensively at the chemistry of manure as well as the microbial population shifts that we might have in a foaming manure pit.
MAYER: Foaming incidents seemed to take off around the time an ethanol byproduct called dried distiller's grains became a common ingredient in swine feed.
HOFF: It's a very high-fiber feed and in some cases combined with a higher fat content. So those two components are issues, or at least avenues, that we're pursuing in the research business.
MAYER: But Hoff says they haven't been able to make a conclusive connection between the distiller's grains and foam. Until a cause is isolated, farmers are at a loss for preventing the problem. So they're stuck with Band-Aids. Hill pours some Rumensin onto the bubbling brown milkshake and uses a long stick to gently mix it in. Reinert watches with anticipation.
KENT REINERT: I don't know. Will you be able to see it? Do something or...
HILL: No, no.
REINERT: It'll quite take a little while...
MAYER: There's no immediate impact. But after two weeks, Hill reports improvement. The foam isn't completely gone, but it's consistently lower. He has quieted the milkshake this time. But he and others remain eager for a more permanent fix. For HERE AND NOW, I'm Amy Mayer in Ames, Iowa.
HOBSON: And coming up next, Apple launches iTunes Radio today. What will that mean for Pandora and other streaming music services? That story coming up next, HERE AND NOW. Transcript provided by NPR, Copyright NPR.