Beef Cows Produce More Methane During Calving Stage
January 31, 2013

More Greenhouse Gas Emitted During Cow-calf Phase

April Flowers for - Your Universe Online

It is a well-known fact that cattle produce carbon dioxide and methane throughout their lives. A new study, however, pinpoints the cow-calf stage as a major contributor of greenhouse gases during beef production.

The research team estimated greenhouse gas emissions from beef cattle during different stages of life in the new study, recently published in the Journal of Animal Science. Their findings reveal that, depending on which production system farmers used, beef production has a carbon footprint ranging from 10.7 to 22.6 kg of carbon dioxide equivalent per kg of hot carcass weight.

One source of greenhouse gas was surprising, according to Frank Mitloehner, an associate professor in the Department of Animal Science at UC Davis.

"If you look at everything that contributes to greenhouse gases through the beef supply chain, then it is the cow-calf that produces the greatest greenhouse gases," Mitloehner said.

The cow gives birth to the calf during this phase and nurses it for six to ten months, eating rough plants like hay and grasses. The bacteria in the cow's gut, which produce methane, thrive on these plants.

"The more roughage is in the diet of the ruminant animal, the more methane is produced by the microbes in the gut of the ruminant, and methane comes out the front end," Mitloehner said.

Cattle in feedlots, in contrast, eat mostly corn and grains. The methane-producing bacteria cannot use corn and grains as effectively, cutting down on the amount of methane produced.

Because methane has a greater capacity to trap heat in the atmosphere than carbon dioxide, it is one of the most important greenhouse gases.

In recent years, the beef cattle industry has been paying close attention to greenhouse gas emissions.

"We are doing a lot to measure and mitigate our impact," said Chase Adams, director of communications for the National Cattlemen's Beef Association.

A previous study, published in the Journal of Animal Science in 2011 by researcher Jude Capper, revealed that the beef industry currently uses significantly less water and land than 30 years ago. The carbon footprint of the industry has been reduced by 16.3 percent per billion kilograms of beef produced.

The current study reveals that beef producers can further reduce the carbon impact by using new technologies like growth promotants. Consumers are often unsure of these methods, however, and choose organic beef or beef with reduced amounts of growth promotants.

"The technologies many consumers are critical of are those that help us receive the greatest environmental gains," Mitloehner said.