Feed Additive Reduces Methane Emissions

Enough about gas stoves. Let’s talk about cows.

Cows enter into the discussion of climate and also considerations of air quality. That’s because they are emitters of methane, a powerful greenhouse gas that also contributes to the formation of ozone pollution.

So how do cows make methane? There’s no delicate way to put it: Cow burps and flatulence put out methane, which forms in the cow’s stomach through a process called enteric fermentation. Amazingly, 70% of the agricultural emissions of cows and other grazing animals is due to this process. And livestock produce most of the human–induced emissions of methane. When expressed as “CO2–equivalents,” global emissions from livestock production contribute 15% of total anthropogenic greenhouse gas emissions.

Working on reducing these emissions could make a dent in the climate problem, so a lot of research has gone into how to alter the cows’ diet to minimize methane emissions. Several studies have shown promising ways of doing that, but the supplements tested have also been costly and had side effect of reducing the meat quality. A recent study has shown that there’s a straightforward way to reduce the methane emissions of cows without these factors that affect the ranchers’ bottom line: put a little seaweed into their feed!

Adding either a half– or quarter–percent of seaweed to the feed reduced methane significantly, with the low treatment (0.25% or about 50 grams seaweed) giving about a 50% reduction and the high treatment (0.50% or ~90 grams seaweed) giving around 70% reduction. And the effects were immediate and persisted throughout the study, as shown in the figure above. In addition, the overall feed efficiency was increased (i.e., a lower feed cost per unit weight gain). Bottom line, the authors note that “These feed cost reductions in combination with significantly reduced CH4 emissions have a potential to transform beef production into a more economically and environmentally sustainable red meat industry.” The next steps would include developing the infrastructure for producing a high quality seaweed product in both oceanic and land–based systems.