Burps, Bottles, and a Bay in Tasmania

by Futoshi Tachino

On Tasmania’s east coast, the tides in Spring Bay don’t just bring boats to harbor; they feed a farm. Here, Sea Forest cultivates a native red seaweed, Asparagopsis, that—when fed in tiny amounts to cows—can throttle the methane produced in their stomachs. It’s a climate fix born of the shoreline and aimed squarely at one of Oceania’s knottiest problems: livestock emissions. In both Australia and New Zealand, agriculture is a top emitter, and enteric methane from ruminants is the elephant (really, the cow) in the room. What’s different in Tasmania is that the solution now has a retail label, not just a lab result.

The science came first. Over the past five years, controlled trials have shown that Asparagopsis can cut cattle methane dramatically—often by half or more—without hurting meat quality or animal growth. A 2021 study led by UC Davis reported up to an 82% reduction in beef-cattle methane with minuscule inclusion rates, while an earlier Australian trial by Kinley and colleagues demonstrated near-elimination of methane in high-grain beef diets at feedlot scale. Results in dairy have been more variable but still substantial in many settings, with several studies showing 50–65% reductions under controlled conditions.

Tasmania is where those findings crossed the farm gate. In mid-2024, Ashgrove Dairy began feeding a stabilized Asparagopsis oil to part of its herd and launched “Eco-Milk” in supermarkets across the state—an everyday product marketed on the strength of lower enteric methane. Reported on-farm cuts hovered around 25% in the early phase, a pragmatic figure reflecting pasture systems and careful dosing rather than idealized lab diets. But the bigger milestone is social: shoppers could, for the first time, pick up milk shaped by a methane-cutting seaweed grown a few hours away along Tasmania’s coast.

What makes the Tasmanian approach distinct isn’t just geography; it’s formulation and delivery. Sea Forest now produces multiple formats—oils blended into feed, pellets, and solid “lick blocks” that animals self-dose from in the paddock—designed for Oceania’s pasture-based herds that don’t eat a total mixed ration twice a day. That matters, because many methane inhibitors (like the well-studied 3-NOP) work beautifully in barns but are harder to deliver to animals grazing on ryegrass kilometers from the dairy shed. A seaweed-based additive that can live in a block or a drench broadens the use-case.

The regulatory scaffolding is also maturing. In March 2025, Standards Australia published AS5404:2025, a national product standard for Asparagopsis feed materials that sets testing, contaminant limits, shelf-life, labeling, and traceability—essential for farmer confidence and export markets. And because Asparagopsis is treated as a feed ingredient rather than a veterinary drug in Australia, producers can supply it within existing feed rules so long as safety and labeling criteria are met. Together, these moves turn “interesting seaweed” into a defined commodity with obligations and assurances.

Does it actually work on real farms? The short answer is yes, with caveats that researchers are frank about. Efficacy depends on diet composition (beef feedlot vs. high-forage dairy), inclusion rate, and delivery method. Trials show stronger, more consistent methane cuts in beef systems and high-concentrate diets than in pasture-heavy dairies; nevertheless, multiple Australian field studies now report meaningful reductions in grazing herds using liquid and pelleted Asparagopsis, with no negative impacts on milk safety.

Safety is the other pillar, and it’s getting the scrutiny it deserves. The active compound in Asparagopsis is bromoform, which disrupts the final step of microbial methanogenesis in the rumen. Peer-reviewed work to date indicates that, at practical feeding rates, residues in milk and meat remain at or below detection limits and within safety thresholds; sensory panels have also found no organoleptic differences in milk from Asparagopsis-fed cows. Ongoing studies continue to monitor iodine and bromine metabolism, and regulators are insisting on transparent residue testing as the industry scales. That vigilance is appropriate—and part of what will make consumers comfortable choosing low-methane milk and beef.

Scaling up is the hard part. Seaweed aquaculture has to deliver consistent biomass, bromoform content, and price—through storms, heatwaves, and biofouling. Sea Forest and peers are building out ocean leases and land-based tanks, while governments are testing incentives. In late 2024, Tasmania earmarked funding to put Asparagopsis into tens of thousands of cattle across dairy and beef farms, helping bridge early-adoption costs and generate the data investors and grocers want to see. If that sounds like industrial policy, it is—tied to a resource that Oceania can grow at scale along its vast coastlines.

The market signal needs to keep pace. Ashgrove’s Eco-Milk has been priced modestly above generic milk and is testing whether consumers will pay a little more for a product with a measurable, local climate benefit. Early coverage suggests cautious optimism: if shoppers accept a small premium—and if supply chains (think: large retailers, airlines, quick-serve restaurants) start to preference low-methane dairy and beef—Asparagopsis could move from niche to normal. The precedent from cage-free eggs and deforestation-free soy is clear: procurement policies can change entire categories.

For Oceania, the upside is strategic. A shore-to-shelf climate solution built in the region, suited to pasture systems, and already sitting in supermarket fridges is rare. It complements—rather than competes with—electrification and reforestation; it tackles a methane stream with fast climate payback; and it can travel across the Tasman, where New Zealand is searching for tools that fit grazing dairy at national scale. The risks—supply chain hiccups, variable efficacy, and the need for ironclad safety data—are real, but they are exactly the kind of challenges standards, transparency, and patient capital are designed to solve.

The image that sticks with me is simple: a bottle of milk that owes its climate claim to a living edge of the sea. It’s a reminder that some of our best decarbonization tools aren’t abstract technologies or far-off megaprojects. They’re biochemistry and husbandry, tuned to a place, priced for a family grocery shop, and carried home in a backpack.

Sources

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