This entry is the latest in a series on innovations in the climate and energy world.
The greenhouse gases that come from livestock are silent but deadly. Conventional wisdom, originating in a 2006 UN Food and Agriculture Organization report, says that livestock are responsible for 18 percent of global emissions, though a 2009 article by Robert Goodland and Jeff Anhang in World Watch magazine puts the number as high as 51 percent. (These numbers were so controversial, and received with such skepticism—including within Worldwatch’s own Climate and Energy team—that a discussion forum was set up right here at ReVolt).
A large fraction of livestock emissions are the result of the methane that cows and other ruminants emit—in the case of cattle, between 90 and 180 kilograms annually. This is equivalent to 1,800 to 3,600 kilograms of carbon dioxide-equivalent.
A cow’s diet has a great deal to do with how much gas it produces. Substituting alfalfa and flaxseed for a portion of the corn and soy put into cow feed was found to reduce methane emissions by 14 percent (and sweeten their breath, a bonus!) on at least one farm. New research out of Newcastle University in the U.K., however, shows that this might be small potatoes. Coriander and turmeric, spices that are commonly used in curry dishes, were found to reduce livestock methane emissions by as much as 40 and 30 percent, respectively, when added to feed.
The researchers, Mohammad Mehedi Hasan and Abdul Shakoor Chaudhry, added ground spices (they also tested clove, cinnamon, and cumin) to an in-vitro solution meant to replicate the contents of the animals’ rumen, and then measured the methane released compared to a control. Although bacteria from a sheep’s rumen were used, Hasan and Chaudhry believe that the results apply to cows as well, as their rumens are very similar. Further tests may be coming soon.
The spices make the digestion process more efficient, eliminating bacteria that form methane while stimulating bacteria that aid digestion. Methane is produced as a byproduct of digestion, and the reduction in methane production would therefore lead to an increase in meat and milk yield without changing the amount of feed.
Does it pass the laugh test?
I don’t think anybody would question the link between diet and the buildup of gas within the digestive tract, and spices have long been used as pseudo-antibiotics. There’s no reason for this particular effect to be believable based on the human experience, but since cows have four digestive compartments, I’ll buy it.
Does it have that WOW factor?
At second glance.
At first this just seems like a quirky little story, but enteric fermentation (production of methane within the digestive tract) is responsible for roughly a quarter of livestock’s emissions, or 4.5 percent of global emissions in FAO’s conservative estimates. So reducing this amount by 40 percent would lower worldwide emissions by almost 2 percent. Wow.
What does it bring to the table?
An alternative to antibiotics.
What is not clear from articles about this research (the study itself has yet to be formally published) is how this 40 percent reduction from a control case relates to what currently exists in the livestock sector. Antibiotics reduce methane emissions as well (as a side benefit to increased meat and milk yields), so current emissions may be significantly below what Hasan and Chaudhry used as a control.
However, the use of antibiotics in livestock production is very controversial, largely because of worries about rising antibacterial resistance. The U.S. Food and Drug Administration released a draft guidance in June 2010 asking livestock producers to use antibiotics on their animals only when “necessary for assuring animal health,” but the agency has yet to take legally enforceable action. The European Union banned the use of antibiotics in feed in 2006.
So even if the use of turmeric or coriander merely replicates the effects of the antibiotics in preventing the formation of methane, this finding could have important implications.
How close is it to commercialization?
Technically? Probably close. But financially…
It shouldn’t be hard to spice up livestock feed on large ranches, although ironically this would be one climate-friendly strategy that becomes less practical the more you move away from the industrial agriculture practices that do such environmental damage. Any given rancher shouldn’t have much difficulty adding turmeric or coriander to feed if the economics work. But the overall cost isn’t clear. Ranchers would see benefits in the form of increased yield, but input costs would be high.
A quick back-of-the-envelope calculation: An adult cow, if forage quality is average, eats about 28 pounds, or 12.7 kilograms, of dry forage each day. If 50 milligrams of coriander were added per gram of dry forage, this would mean that 0.6 kilograms of coriander would be needed per cow, per day. The contract price for coriander on the Multi Commodity Exchange of India is roughly US$70 per 100 kilograms, which means that the coriander alone (not including transportation, labor, and other costs) would add about $150 to the cost of feeding an adult cow for a year.
How scalable is it?
Not very, probably.
While a single rancher might be able to easily incorporate coriander or turmeric, doing this on a large scale would completely transform the coriander and turmeric markets. Hasan and Chaudhry were using concentrations of up to 90 milligrams of spice per gram of forage, which is a not-insignificant amount. Turmeric is a specialty crop produced almost exclusively in India, and for this discovery to have any legs it would likely have to be blended with other, more readily available spices.
Coriander is more widely grown, with an annual fruit crop of roughly 600,000 tons in 1996 (although the weight of the seeds alone is obviously far smaller). It is grown is many places around the world, but India and the countries of the former Soviet Union are the main producers. The United States was home to 94 million cattle in 2009, which, according to the rough calculation above, would consume 20 million tons of coriander each year.
What is the biggest obstacle to success?
Aside from all this? Rancher buy-in.
Industrial livestock feed currently consists of grains that can be acquired cheaply—often corn. It is unclear whether the economics of using spices to increase meat and milk yield will be enough on their own to stimulate usage (ranchers were keen on antibiotics, but those also provided health benefits that coriander would not), and so it would probably take some sort of carrot or stick to see the use of coriander for livestock come to fruition. But consumers’ growing interest in organic, non-antibiotic meat can’t hurt.
The final word(s):
Don’t hold your gas.
It’s possible that your local natural-foods supermarket or farmer’s market may eventually tout its coriander-fed beef (although unless ranchers plan on spicing their grass or giving their livestock daily coriander pills, it’s hard to see how grass-fed and coriander-fed can be combined). Even so, the discovery that curry spices reduce methane production in ruminants will likely not make a significant contribution to mitigating climate change. Cows on treadmills, though? Now we’re talking!