Agriculture is a major contributor to greenhouse gas emissions, and around a third of the emissions from the sector are thought to come from livestock producing methane.
Emissions from the world’s nearly 1.5 billion cattle are a major source of methane, a powerful greenhouse gas. Preliminary research (from a 2015 Australian Study) has indicated a small amount of marine algae added to cattle feed can reduce methane emissions from cattle gut microbes by as much as 99 percent.
In fact, this study indicated a small amount of seaweed practically eliminated methane emissions from cattle gut microbes in lab conditions. A compound found in some seaweed disrupts enzymes used by the microbes to produce methane.
Now, researchers in California and elsewhere are experimenting with seaweed as a dietary additive for dairy cows that can dramatically cut their methane production. (In an attempt to curb methane as a source, California has introduced regulations calling for dairy farmers to cut methane emissions from their 1.7 million cows by 40 percent over the next decade.)

Cow digestion relies on millions of microbes in their guts processing and fermenting high-fiber foods. This process allows the animals to survive on a diet of grass, but it also produces large quantities of methane. Cattle/cows constantly burp and emit the methane being produced in their stomachs. Feeding seaweed to cows could slash the amount of climate change-inducing methane emissions from their burps.
While their early results are yet to be released, so far, the California researchers are seeing substantial emission reductions – the numbers they are seeing are reported to be “amazing,” well beyond the target that farmers will need to reach in California.
However, dietary supplements for cows have been known to end in disappointment after showing great promise in the lab that failed when the animals rejected the foodstuff. To produce feed that the cows enjoy, the researchers cut a small amount of red seaweed with cattle feed and molasses. A panel of tasters detected no differences among the different cows’ milk eating feed with seaweed vs. those eating their regular feed.
Seaweed is an appealing supplement not only because of its gas-limiting effects, but because it is so easy to grow. Irish farming organizations and politicians have already called for more research into seaweed as livestock feed, citing the island nation’s ample supplies of marine algae.

In fact, one Irish feed manufacturer is already using seaweed in its livestock products. Ocean Harvest Technology Ltd, a global company producing animal feed ingredients centered on the natural bioactive properties of seaweed, recently introduced the first North American pork products raised on OceanFeed™ Swine, their proprietary, seaweed-based feed ingredient specifically formulated for pork. Ocean Harvest partnered with Heritage Foods, a commercial farming company making heritage breed poultry and livestock raised on pasture without antibiotic growth promoters.
U.S. producers for Heritage Foods using the OceanFeed™ Swine, report that their pigs are more uniform and larger in size, are healthier with reduced scouring and mortality rates, and use feed more efficiently due to the natural prebiotic like effects of this seaweed blend.

Coincidentally, Howard Hanna, a nationally recognized Chef from The Rieger here in Kansas City, MO stated: “At the end of the day, I care about how pork tastes, that is the key test for me. We were proud to be the first restaurant in North America to try this seaweed fed pork, and as a chef, I can attest to the quality and my customers like it. The fact that this product also furthers the humane treatment of pigs in addition to being a high-quality pork, adds to my support of this type of product.”
Sources:
https://e360.yale.edu/features/how-eating-seaweed-can-help-cows-to-belch-less-methane