From additives to hands free farms: Can technology decarbonise UK agriculture?



In 2022, then environment secretary George Eustice – responding to the Environmental Audit Committee over failures by the Department for Environment, Food and Rural Affairs (Defra) to progress its decarbonisation targets – sheepishly diverted to technology. He was “optimistic”, he said, about the role it would play in slashing agricultural emissions. 

Eustice’s uneasiness before the committee betrayed his predicament. Agriculture contributes less than 1% to the UK economy, but is responsible for around 11% of the country’s total greenhouse gas (GHG) emissions. This figure hasn’t budged much in the last decade. For this, it produces around three-quarters of domestic food consumption – and uses a whopping 71% of land, 21% of which will be needed by 2050 to sequester carbon, as per the Committee on Climate Change’s (CCC) sixth carbon budget.

The government already offers what industry insiders describe as ‘generous’ subsidies for land afforestation (hedgerows and woodland). But to meet the CCC’s recommendation that agriculture-related GHGs reduce by 64% by 2050, it also purports, among other things, to reducing meat consumption by 35%. This move would be so politically unpalatable that Rishi Sunak, the then Prime Minister, conjured up a meat tax proposal (that never actually existed) purportedly just so he could scrap it to garner populist ‘anti-woke’ headlines. 

That then leaves, as Eustice says, the heavy lifting to technology and innovation. Last year the government offered a minimal £168m in the Improving Farm Productivity grant. So, the question is, what technology is emerging?

Scientists at SRUC measured methane using respiration chambers. Image credit | Ed-Robertson

Tackling enteric fermentation 

Despite that 11% share of GHG, it might be surprising to learn that agriculture is only estimated to be responsible for 1.9% of the country’s carbon dioxide emissions. One of the sector’s big impacts comes from methane emissions, for which it produces 49% of the country’s total, mostly from livestock. 

In the rumen, one of four stomachs possessed by cattle (sheep, cows, goats), there are millions of microorganisms that decompose and ferment plant materials, a function called enteric fermentation. The digestive process produces lots of methane, 92% of which emanates from the animal’s nose and mouth. 

Naturally, inhibiting or altering this process to reduce these gases has become a target for scientists. Ten years ago Rainer Roehe, a professor of animal genetics and microbiome at Scotland’s Rural College (SRUC), started measuring the methane emitted from individual animals using large temperature and humidity-controlled respiration chambers he and his colleagues built at the university. An animal spent three days in the chamber and the air entering and leaving was measured for methane, hydrogen and CO2. The difference determined how much of each was being emitted. 

The researchers discovered that some animals, despite being the same breed and having the same diet and living environment, produced half the emissions of others. To understand more, in the abattoir they took samples from 300 cow rumen and examined their microbial genes using cutting-edge molecular techniques. Together with the emissions data they could eventually predict, based on their microbiome genetics, which cows would emit more or less gases than others.

Using this work, Roehe is now working with Genus, a leading breeding company that sells to 50% of the beef and dairy industry, under a project called Climate Smart Beef Genetics to use the method to breed lower-emission cows. The team predicts a microbiome-driven breeding strategy could reduce methane emissions by up to 17% per generation or 7% per year or by up to 50% in 10 years, if selecting only for emissions (though it’s likely other factors will be considered, such as growth rate). One bull inheriting these genes can be mated by artificial insemination with up to 100,000 cows per year to, hopefully, produce low-emitting offspring.

Through the Defra and UK Research and Innovation-funded Climate Smart Beef Genetics, they have selected sires inheriting low and high methane emission genes and will test their 240 offspring over the next two years to see if they produce less methane emissions than their parents. If successful, Roehe believes they could provide semen from microbiome-driven breeding bulls to the world through Genus’ network. “With these sires we can have an impact not only on the UK population but worldwide, which makes this very cost-effective,” he says.

Meanwhile, science-based firm DSM-Firmenich is achieving something similar by a different method: a feed additive. Under a climate change-induced innovation programme initiated by the company in 2008, its scientists discovered, with the help of 30-40 years of previous research on enteric methane, that methane produced in the rumen could be reduced by inhibiting a specific enzyme. After further research they discovered a molecule that could do the job: 3-nitrooxypropanol. 

This work is encompassed in the feed supplement Bovaer, which, as evidenced in more than 100 trials, can reduce enteric methane emissions by around 30% in dairy cows if mixed into their feed. Diet and environment impact its effectiveness, so the company has created a peer-reviewed methane-reduction formula – including Bovaer dosage, neutral detergent fibre and fat percentage in feed – to guide farmers. This also enables them to calculate the methane reduction in UK carbon footprinting tools.

The product was approved for use in the UK last December, after previously being licensed in the EU – the first and only additive of its kind to achieve this, says EMEA commercial director Dennis Rijnders. DSM is already building a production factory in Scotland and selling to giants such as Arla and Danone, as well as Marks & Spencer, which is using it for its entire RSPCA-assured dairy milk pool, funded through its Innovation Fund. But it is small fry for now (270,000 tonnes), largely due to the cost. This adds up to less than €0.01 per litre of milk – minimal for the consumer – but for a farmer with 150 cows this would cost up to €12,000 a year, a “sum farmers won’t pay alone”, says Rijnders. 

Eventually, feed additives like Bovaer, and other similar solutions, could be combined with selectively bred cows for greater impact, says Roehe. But he adds: “Breeding is permanent and more cost effective as it can be spread across the world through genetics.”



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