A Sprinkle of Seaweed can Eliminate Greenhouse Gas Emissions from Cattle

One could say that we have a beef with the rising amount of methane (CH4) in the atmosphere: although this powerful greenhouse gas breaks down much faster than carbon dioxide, it traps 86 times more heat than CO2 over a 20-year span. Human activity has been the chief source of the increase in modern CH4 levels, having increased by about 150 percent since 1750, with about half of all human-generated methane coming from our livestock — particularly from the planet’s 1.5 billion cows. However, a new study has found that spicing a cow’s feed with simple seaweed can cut a burping bovine’s methane production by up to 99 percent.

When it comes to livestock-related methane emissions, the chief culprits are a group of animals called ruminants — animals with specialized stomachs that ferment their food to break the material down before it enters the intestines for digestion. Common examples are giraffes, elk and deer, with some of the more common domestic animals including cows, goats, camels and sheep. Amongst domestic livestock, cows are the largest source of CH4, accounting for 65 percent of total methane emissions from livestock.

Contrary to the popular joke, this methane does not come from Bessie’s flatulence: rather, about 90 percent of an individual cow’s methane is burped up. A major component of a ruminant’s digestive process is the use of bacteria in its stomach to ferment the digested food, and this bacteria produces the methane in question. Through regurgitating the cud back up to be re-chewed, this methane is expelled through the cow’s mouth.

However, there may be a way to curtail the high amounts of CH4 being produced. Researchers at Australia’s James Cook University employed artificial cow stomachs to test the effect of 20 different species of seaweed on the fermenting rumen that would be found in the average bovine’s belly.

Of the tested seaweeds, Asparagopsis taxiformis, a form of red algae, had a major impact on the fermentation process: A. taxiformis contains a chemical called bromoform (CHBr3) that interferes with the digestive enzymes secreted by the stomach’s microbes that contribute to methane production. And not much of the weed was required to produce a substantial effect: with a mixture of only 2 percent seaweed, methane emissions dropped by 70 percent.

This research came about following a Canadian study that found that cattle that ate seaweed thrown into their pastures by storms were healthier and heftier than cattle found farther inland, implying that there may be even more benefits to feeding cows seaweed.

While this development sounds promising, the researchers caution that our current seaweed cultivation industry doesn’t have nearly enough capacity to contend with the sheer amount of cattle we raise, estimating that it would take nearly 500,000 acres of seaweed farms to supply the 92 million cattle found in the U.S. alone. But until a practical method of implementing this idea is devised, it might just be best to simply cut back on meat and dairy products produced by cows.