Dairy cows and cattle were found to reduce their methane emissions by 50% and 82% when marginal amounts of seaweed were added to their feed
DAVIS, CALIF. – Tulare County dairy emissions have not gone unnoticed. As Peter Parker’s late uncle Ben might say: “with great cows, comes great greenhouse gas emissions.” But universities are considering a fix that might help limit the noxious gas cows release.
A new study from University of California Davis finds that “a bit of seaweed” in dairy feed can reduce greenhouse gas emissions (GHG) from cows by 50%. According to 2019 statistics, Tulare County’s leading agricultural commodity is milk. It grosses over $1.6 billion and represents 21.5% of the total crop and livestock value. The UC Davis study notes that agriculture is responsible for 10 percent of GHG in the U.S., and half of those come from cows and other ruminant animals that belch methane and other gases throughout the day as they digest forages like grass and hay.
In the new study, Ermias Kebreab, professor and Sesnon Endowed Chair of the Department of Animal Science and director of the World Food Center along with his Ph.D. graduate student Breanna Roque tested whether those 50% reductions were sustainable over time. They fed cows a touch of seaweed every day for five months, from the time they were young on the range through their later days on the feed lot. In 2018, Kebreab and Roque found that they were able to reduce methane emissions from dairy cows by over 50 percent by supplementing their diet with seaweed for two weeks. The seaweed inhibits an enzyme in the cow’s digestive system that contributes to methane production.
“Only a tiny fraction of the earth is fit for crop production,” Kebreab explained. “Much more land is suitable only for grazing, so livestock plays a vital role in feeding the 10 billion people who will soon inhabit the planet. Since much of livestock’s methane emissions come from the animal itself, nutrition plays a big role in finding solutions.”
Four times a day, the cows ate a snack from an open-air contraption that measured the methane in their breath. The results were clear. Cattle that consumed seaweed emitted much less methane, and there was no drop-off in efficacy over time.
As a kicker, cattle who were put on the seaweed feed grew to the same size as their regular feed counterparts, and they reduced their GHG emissions by 82%.
“We now have sound evidence that seaweed in cattle diet is effective at reducing greenhouse gases and that the efficacy does not diminish over time,” Kebreab said. “This could help farmers sustainably produce the beef and dairy products we need to feed the world,” Roque added.
In the study released in March, over the course of five months last summer, Kebreab and Roque added scant amounts of seaweed to the diet of 21 beef cattle and tracked their weight gain and methane emissions. Cattle that consumed doses of about 80 grams (3 ounces) of seaweed gained as much weight as their herd mates while burping out 82% less methane into the atmosphere.