Gas-X for Cows? How to Lower Methane Release in Cows
A supplement added to the feed of high-producing dairy cows reduced methane emissions by 30 percent, and could have positive ramifications for lessening global climate change and greenhouse gas (literally), according to an international team of researchers.
In addition, over the course of the 12-week study conducted at Pennsylvania State University’s dairy barns, cows that consumed a feed regimen supplemented by the novel methane inhibitor called 3-nitrooxypropanol (3NOP) gained 80 percent more bodyweight than cows in a control group. Significantly, feed intake, fiber digestibility and milk production by cows that consumed the supplement did not decrease.
The findings are noteworthy because methane is a potent greenhouse gas. Fermentation in the rumen generates methane as a result of microorganisms that aid in the process of digestion. The animals must expel the gas to survive. The 3NOP supplement blocks an enzyme necessary to catalyze the last step of methane creation by the microbes in the rumen.
It was important to conduct the study under industry-relevant conditions, said lead researcher Alexander Hristov, a professor of dairy nutrition at Penn State. The researchers published their results in a recent issue of the Proceedings of the National Academy of Sciences called “An Inhibitor Persistently Decreased Enteric Methane Emission from Dairy Cows With No Negative Effect of Milk Production.”
Methane expulsion through belching represents a net loss of feed energy for livestock, Hristov noted, adding that a high-producing dairy cow typically emits 450-550 g per day of ruminal gas produced by fermentation. The spared methane energy was used partially for tissue synthesis, which led to a greater bodyweight gain by the inhibitor-treated cows.
The 48 Holsteins in the study received varying amounts of the inhibitor in their feed and were observed at regular daily intervals over three months. Their methane emissions were measured when the cows put their heads into feeding chambers that had atmospheric measurement sensors, and also through nostril tubes attached to canisters on their backs.
The multiple-compartment stomachs in cattle create the methane, resulting in bovine belches. Despite better digestibility in cattle feed over the years, methane emissions from cattle has risen more than 2% since 1990, said the EPA, because of upward trends in cattle populations.
The conclusions are part of the EPA’s draft inventory of greenhouse gas emissions from 1990 to 2012, a report which is compiled annually and submitted to the United Nations Framework Convention on Climate Change.
According to the report, in 2011 and 2012, the cattle industry was responsible for some 143 and 141 million metric tons, respectively, while natural gas systems produced 130 and 127 million metric tons. Landfills, which used to be the top methane emissions producer, came in third in 2012 at 103 million metric tons.