Changes in livestock production and a trend toward large-scale operations have led to increased concern about odors emitted from farms. This is especially true for swine production facilities.

A recent story in Agri-Times Northwest says five scientists at the Swine Odor Management Research Unit at Ames, Iowa, are trying to unlock the root causes of swine odors. Scientists at the unit have determined that swine diets can be manipulated to reduce odor-causing emissions from pigs.

They have learned, for example, that ammonia and other nitrogen compounds can be reduced by lowering the pigs’ crude protein intake. They do this by replacing some of the soybean meal in the diet with crystalline amino acids.

They’ve also found that the type of fiber fed to pigs affects the amount of ammonia released into the environment. This is high level stuff, resulting from years of study into what makes pig manure stink.

These scientists didn’t just go out to the barn and decide to play around with the pigs’ diet. They had reason to believe what goes into a pig has a direct effect on what comes out of the pig. Others have studied this phenomenon for many years.

I can remember walking into a swine confinement barn back in the 1960s, before swine producers knew a lot about controlling odors. Several hours and two or three showers later I was back pretty close to normal.

I also recall a story told by Ron Miner of Oregon State University in the late 1970s. He and other agricultural engineers at OSU had designed a research project to determine what causes the unpleasant smells associated with pigs.

For the study these scientists secured a room in a small building on the OSU campus. They remodeled the room so they could control the airflow and thus the level of odors. Then they placed a pen in one corner and started feeding five or six pigs.

Their room could be ventilated to a pleasant level or it could be closed up to replicate the worst stench a hog barn has to offer. Other than the pigs and a few instruments, the only furniture in the room was a desk and a chair in the middle.

One day Dr. Miner had the ventilation turned off, the heat turned up, and the odor level cranked up to stifling. He was sitting at the desk recording data when he heard a knock on the door.

A deliveryman walked in. Not all the way in, but the guy opened the door and stumbled backwards.

Pretty soon the driver opened the door again, determined to deliver his package. He was able to squint through the haze well enough to make out the pigs in the corner.

Finally, this fellow got his breath. “What are you doing in here?” he gasped.

“This is a swine research project,” Dr. Miner said. “We’re trying to find out what causes this odor.”

The deliveryman wiped his watery eyes and pointed toward the corner. “It’s them pigs over there,” he stammered.

This farm news was published in the Oct. 11, 2006 issue of Farm World, serving Indiana, Ohio, Illinois, Kentucky, Michigan and Tennessee.