An unusual feed supplement could soon put an end to cow belches, a major source of greenhouse gases.

A Penn State dairy scientist conducted a series of laboratory experiments and a live animal test to develop an oregano-based supplement, which not only decreased methane emissions in dairy cows by 40 percent, but also improved milk production.

Alexander Hristov, an associate professor of dairy nutrition, said that the natural methane-reduction supplement could lead to a cleaner environment and more productive dairy operations.

“Cattle are actually a major producer of methane gas and methane is a significant greenhouse gas. In fact, worldwide, livestock emits 37 percent of anthropogenic methane,” said Hristov. Anthropegenic methane is methane produced by human activities, such as agriculture.

Compared to carbon dioxide, methane has 23 times the potential to create global warming, said Mr. Hristov. Methane production is a natural part of the digestive process of cows and other ruminants, such as bison, sheep and goats. “Any cut in the methane emissions would be beneficial,” said Mr. Hristov.

Experiments revealed another benefit of the gas-reducing supplement - it increased daily milk production by nearly three pounds of milk for each cow during the trials. The researcher anticipated the higher milk productivity from the herd.

“Since methane production is an energy loss for the animal, this isn’t really a surprise. If you decrease energy loss, the cows can use that energy for other processes, such as making milk,” said Mr. Hristov.