Seaweed feed to cut emissions

Dairy cattle on a seafood diet? A seaweed supplement is making a big difference to methane outputs in Tasmania.

Weed to feed: Tasmanian farmer Richard Gardner with Sea Forest founder Sam Elsom inspecting an asparagopsis seaweed sample.

THE concept of eating seaweed was a novelty to many Australians when sushi became popular Down Under in the mid-1980s.

Many would recoil at eating something they associated with lying around on the beach during their summer holiday.

Today, the Japanese-derived delicacy is commonplace in food outlets across the country with few batting an eyelid at its part-oceanic origins.

But that’s seaweed for human consumption.

In the paddocks and dairy yards of Australia, seaweed for consumption by cattle is still a novelty.

But Tasmanian farmer Richard Gardner reckons that may soon change, much like the explosion of sushi outlets on Australia’s shopping strips a generation ago.

Research conducted in ­recent years by the CSIRO, the James Cook University and Meat and Livestock Australia has identified asparagopsis seaweed as an effective feed supplement to reduce emissions.

Richard, who operates his family farm, Annandale, at Tunbridge, 100km north of Hobart, is conducting a large-scale trial of asparagopsis seaweed, co-ordinated by Fonterra and Sydney-based business Sea Forest.

His farm was chosen because Tasmania has a suitable climate to grow asparagopsis seaweed and a long-established flexible feeding and milking system.

“We have done lot of work on carbon auditing and found that our farm business is a significant emitter of greenhouse gases, particularly methane from livestock,” Richard said.

“Asparagopsis seaweed looks like the first viable option we have had to achieve major emission reductions, and it could potentially be a big part of the future sustainability of our industry.”

CLIMATE’S RIGHT

RESEARCH trials have suggested that when aspara­gopsis is fed to livestock in small amounts, it not only reduces methane emissions but may also support production.

As part of the trial, Fonterra will monitor milk production and quality to see whether output is boosted.

“The dairy and livestock industries have got some challenges to address in terms of climate change and we want to make sure we’re doing our bit,” Fonterra sustainability manager Jack Holden said.

Testing led by CSIRO has shown that asparagopsis has the potential to reduce the emissions from livestock by more than 80 per cent.

Farmers only need a small, but regular, amount of this seaweed in their cow feed to significantly reduce a cow’s methane emissions.

Sea Forest founder Sam Elsom said his company’s seaweed supplement paves the way “for the introduction of the first climate-positive meat and dairy products.”

Seaweed for feed is not the only change in the composition of the region’s agriculture.

The Tasmanian Midlands is known as the heart of Apple Isle’s fine-wool Merino country, but Richard says dairy is just as conducive to the district.

“Our Annandale farm had a huge transformation since the 1990s and irrigation has been a major catalyst in that change,” he said.

“Annandale was a dryland sheep property when we first arrived, with mainly Merino sheep.

“Once it was confirmed that the Midlands Water Scheme (a massive water-led agricultural and food bowl rejuvenation) was going ahead, we made the decision to start dairying.”

ONCE IS ENOUGH

RICHARD’S total farm area covers 2400ha with 615ha centre-pivot irrigation.

His business milks 1250 cows from 336ha of irrigated land, producing and supplying milk to Fonterra.

“In the 2020 financial year, we began conversion to once a day milking, and have been solely converted for all of the 2021 financial year,” he said.

Richard said the conversion to once a day milking was all about business sustainability. “Easier on staff, cows and infrastructure,” he said.

“Data from New Zealand shows that within a few years, (once a day milking) can be equally profitable as twice a day, and our experience in our first full year is that we have exceeded per cow production expectations.”

Richard operates the farm alongside wife Emily and their daughter Molly also has an interest in ecological farming.

Their farm manager, Joel Hazelwood, works with six full-time employees.

“I’ve been dairy farming for seven years and I call my farm a non-traditional dairy – it’s not in a typical dairy region and shifted to dairy from sheep and cropping,” Joel said.

“I split my work time between Annandale, which is a mixed dairy and sheep farm and Seedhouse Tasmania, which is a manufacturer and wholesaler of bagged stock, bird and poultry feeds for the Tasmanian market.”

ROOM TO MOVE

ANNANDALE’S milking area covers 336ha but there’s room to move — the usable holdings for dairy is 593ha in total.

Dairy represents 70 per cent of the business turnover while Merino dual-purpose sheep accounts for 13 per cent and cropping as support for livestock enterprises rounds out the remaining 17 per cent.

The annual rainfall ranges from 450mm to 500mm a year.

“We’ve had good rain and pasture growth this year, although maintaining high levels of pasture quality has been a challenge,” Richard said.

“Clover has been a bit slower to get going, as it hasn’t been as warm and there have been lower light levels, but I’m going through the analysis required to confirm that.

“Weather conditions can change quickly at any time of the year.

“In summer, maximum temperatures average around 24C and in winter the average maximum is 12C.

“It also receives low rainfall compared to other regions of Tasmania.”

The topography of Annandale is relatively flat with some rolling hills and has mostly a shallow duplex soil.

While seaweed has been the latest staple on the Gardners’ farm, ryegrass and white clover have provided reliable fodder in past years, with about 8-10 per cent renovated per year.

After reading his weekly Fonterra newsletter, Richard’s interest in seaweed as fodder was piqued by an article announcing a partnership with Sea Forest to trial Asparogopsis.

“I’d been following the research into technical solutions to methane emissions in ruminants since I first became aware of climate change science in 2003 while on Nuffield Scholarship,” he said.

ON TRACK

RICHARD said his family was interested “in doing what we can for sustainability, and this is a great opportunity to do something meaningful in fight against climate change.”

Annandale’s milking operations involve a two-herd rotation graze of 625 cows each.

Livestock assigned paddocks are roughly 10ha each with about 26 per cent of property managed for conservation.

The two herds have a grass-dominant diet, and consume about 14.5 tonnes of dry matter per hectare of pasture, with more than 70 per cent of the diet home grown.

Richard is aiming for 80 per cent of diet to be pasture with less than one tonne of grain per cow.

“The farm has grown from a production of 3.25 million litres in the first year we started — financial year 2015 — to producing 5.81 million litres last year,” he said.

“We’re on track to achieve similar total production this year, milking 50 more cows but milking once a day.

“The production drop in the first full year of once a day milking from twice a day in the 2018-19 period has been only 9.5 per cent, which is a lot better than expected.”

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