Can biotechnology save Earth from being cooked in a cloud of cow burps and farts?
Cattle flatulence is no laughing matter. Its chief component is methane, or CH4, which is 25 times more effective in trapping heat from the sun than carbon dioxide. The microbes that live in a cow’s digestive tract produce methane in a process called “enteric fermentation.” The resulting gas is passed either through a belch or a fart.
About 71 percent of agricultural methane emissions in the U.S. are attributable to this process of “enteric fermentation,” most of which comes from beef and dairy cattle. Another quarter of agricultural methane emissions come from the breakdown of organic matter in manure on dairy and swine farms.
In a new paper appearing in the journal Animal Frontiers, two University of California, Davis scientists, Frank Mitloehner and Clayton Neumeier, argue that certain controversial biotechnological options -- hormones and antibiotics among them -- actually help farmers clear the air. Modern methods that increase production efficiency mean that cows are consuming fewer resources and emitting less waste per pound of beef that ends up on the plate.
"We are increasing the amount of product with same input,” Neumeier said in a statement.
One way that farmers beef up cows is by seasoning a cattle’s diet with ionophores, which are antimicrobial molecules that can decrease the amount of certain microorganisms in a cow’s digestive tract. While data shows that the methane-inhibiting effects of ionophores are likely minimal, “increases in production efficiency accomplished through supplementing ionophores reaffirm their use as an overall environmental mitigation technique,” Mitloehner and Neumeier wrote.
Food safety advocates may be concerned about the potential for ionophore supplements to contribute to antibiotic resistant bacteria that could infect humans. But in this particular case, the danger may not be as acute. A 2003 USDA study concluded that ionophore resistance is not that likely to pass from one kind of bacteria to another and, thus, was not likely to have a significant impact on human health.
Hormonal implants used to accelerate cattle growth rates, typically given 20 to 40 days before slaughter, may also help relatively reduce emissions, Mitloehner and Neumeier said. They pointed to a 2011 study by Mitloehner and others that put steers in special corrals that trapped emissions. They found that cows treated with a combination of biotechnological mehtods -- ionophores plus implants -- put out about 31 percent fewer greenhouse gas emissions compared to cows not treated with those options.
Removing biotechnological tools like antimicrobials and implants might make it harder for beef producers to match production levels. To make up the difference, farmers would have to increase their herd sizes and use more land, food and water and produce more waste and greenhouse gases, Mitloehner and Neumeier wrote.
“Consumer perception of using these biotechnologies in food production is often negative, in part due to the media focusing on potential negative aspects of biotechnologies,” the authors wrote. “Phrases like ‘hormone-free’ and ‘antibiotic-free’ are common, attractive selling points for the public. To the vast majority of the population that maintains a scant understanding of food production, it is unsurprising that these biotechnology-free properties are the preferred option.”
There are also some nutritional approaches to help cows fight gas. French cattle feed company Valorex has been developing a new nutrition program aimed at reducing methane emissions from cows. The program, dubbed “Bleu-Blanc-Coeur” ("Blue-White-Heart") centers on a diet of alfalfa, linseed and grass rather than corn and soy. The diet aims to add more omega 3 fatty acids, which are less prevalent in corn and soy, back in to the cows’ systems.
At the moment, farmers might shy away from the Bleu-Blanc-Coeur diet due to its expense. Corn and soy are plentiful and cheap.
"The more the animal eats rich food and food with an imbalance between omega 3 and omega 6 [the fatty acid in corn and soy], the more methane it releases,” Valorex spokesman Jean-Luc Besset told German news service Deutsche Welle this past March. “A cow releases between 600 to 800 liters of methane a day -- but with our feed, we've reduced emissions by 20 percent.”
Roxanne has liked science ever since she started watching "Bill Nye the Science Guy" on Saturday mornings over a bowl of sucrotic O's. She especially likes writing about...