Dairy Cows (IMAGE) Penn State Caption Dairy cows in different regions of the world, depending on their diets, their genetics and their management systems, belch different amounts and intensities of methane, said lead researcher Alex Hristov, professor of dairy nutrition in Penn State's College of Agricultural Sciences. Credit Wisconsin Department of Natural Resources Usage Restrictions Non commercial use only License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.