USDA Grant to Fund New Air Quality Research Project at ISU

February 16th, 2005

Iowa State University is one of 11 institutions receiving part of $5 million in new funding from the U.S. Department of Agriculture for air quality research.

The four-year project will study dietary strategies to reduce gas emissions from turkey, laying-hen and growing-finishing cattle operations.

Iowa State is partnering with Purdue University on this $482,000 USDA grant, with $291,000 remaining at ISU. The Iowa State portion of the project will be led by Wendy Powers, associate professor of animal science and environmental extension specialist, and James Russell, professor of animal science.

Powers said the first step is to establish baseline emission measures for ammonia, hydrogen sulfide, nitrogen oxides, sulfur oxides, methane and volatile organic compounds when cattle, laying hens and turkeys are fed typical diets.

"Once we've determined baselines for typical diets, we'll turn our attention to how emissions can be reduced when dietary changes are made," Powers said. "Preliminary studies have shown promise for reducing emissions by manipulating diets. Eventually we hope to develop new dietary recommendations for livestock producers that will improve air quality both inside and outside of production buildings."

The USDA National Research Initiative that provided this funding in 2005 for emissions work with turkey, laying hens and growing-finishing cattle funded a similar four-year project at Iowa State in 2004. It covers growing swine, broiler chickens and lactating cows.

A new Iowa State laboratory facility opened last fall to help researchers study the impact of diet. It consists of eight rooms for housing animals. Each room can accommodate one horse, one lactating cow, two growing heifers, six finishing pigs, 25 turkeys, 60 broilers or 85 laying hens.

Penning, feed and water-handling systems and manure-handling apparatus for each species can be removed from the chambers to accommodate the needs of different species. Powers said this flexibility makes the laboratory the only one of its kind in the nation.

Growing swine was the first animal species tested under the 2004 project. Beginning last September, groups of pigs were fed one of three diets until they reached market weight in late December. The diets included three protein levels. Manure collected from the animal rooms was analyzed for nutrient content to determine the diet impacts.

The new lab has online monitoring capabilities for the each of the gases of interest. Airflow rates into and out of each room are measured as well, allowing the emission rates of each gas to be calculated.

Powers said ammonia concentrations went down as the level of protein in the swine diets declined. "The daily amount of ammonia emitted from the lowest protein diet was 48 percent less than that emitted from the control diet, when adjusted for pig bodyweight," she said. "And the intermediate diet resulted in a daily ammonia emissions mass of 22 percent less than the highest protein diet."

No differences in hydrogen sulfide emissions were found as a result of the diets fed. The lower protein levels did not cause any significant difference in feed efficiency or average daily gain.

The first phase of the new research project will begin April 4 when laying hens are moved into the air emissions laboratory. Todd Applegate, a researcher at Purdue University, has partnered with the egg industry to formulate two diets that will be tested. Laying hens at varying stages of production will be fed either a typical industry diet or a "reduced emissions diet" that incorporates protein and pH modifications, as well as a feed additive.

Applegate also will be involved in conducting preliminary studies with turkeys to determine what dietary formulations hold the most promise for reducing emissions without negatively influencing performance. Once those diets are identified, they will be fed in the Iowa State lab where emissions can be studied. ISU researchers will be in charge of identifying the most promising diets for growing cattle and then testing those diets in the lab.

Powers said the ultimate goal with both of these projects is to find ways livestock and poultry producers can improve air quality by changing animal diets. "As we identify dietary modifications that effectively reduce emissions, we'll make recommendations on those modifications while also sharing information on the cost-benefit aspect of our recommendations," she said.


Wendy Powers, Animal Science, (515) 294-1635,
James Russell, Animal Science, (515) 294-4631,
Susan Thompson, Agriculture Communications, (515) 294-0705,