The Iowa Department of Natural Resources is going to study cow flatulence and other so-called “greenhouse” gases emitted in Iowa. D-N-R spokeswoman Julie Tack says they want to measure the gases to compare them with past levels.She says a 1990 study showed 80 percent of Iowa’s greenhouse gases came from fossil fuels, while other sources were farm animals, landfills, and people. Iowa’s receiving a 25-thousand dollar grant from the U-S EPA to conduct the 18 month study.Tack says the greenhouse gas survey could lead to some changes or improvements in the state to cut the gas emissions. The Center for Energy and Environmental Education at the University of Northern Iowa in Cedar Falls will help the D-N-R conduct the study.