Dairy industry diligence rewarded for emission control efforts
A ‘sense of duty’ rural mindset steered by public pressure drives the momentum of emission reduction strategies in the North American dairy industry. While much is still to be learnt, and many hurdles scaled, constructive methods are making critical advances.
North American-based dairy activities inevitably result in greenhouse gas (GHG) emissions from three distinct sources no matter the level of preventive care. These sources include methane emissions from ruminant enteric fermentation, anaerobic decomposition of manure pits and lagoons, nitrous oxide emissions from fertiliser applications, organic soil cultivation, and crop residue decay.
Since most dairy emissions originate from animals and manure storage, the industry has expended vast efforts into reduction methods including improving how cattle are managed, feed variation availability, and more recently incorporating feed additives specifically designed to decrease enteric emissions.
Some operations are turning to anaerobic digesters (ADs) to address manure storage and management. Manure is collected and placed into these digesters which transform methane into biogas.
The drive for improvement
Farm proximity to heavily populated areas has driven outside interest in dairy industry controls as unwanted odours are a prominent issue for the average urbanite says Doug Reinemann, Professor of Biological Systems Engineering at UW-Madison.
“Public perception and the social license to practice dairy farming near population centres will continue to encourage farmers to address this issue,” Reinemann says. “Of course, this depends on location, but these pressures are real and will drive controls including the adoption of more anaerobic digesters.”
He says ADs are the most effective method of reducing storage emissions and generating electricity from biogas. This technology essentially eliminates manure as a source while producing green energy.
Reinemann notes methane from manure accounts for roughly one-quarter of a farm’s GHG emissions which an AD can eliminate. When producing renewable energy, up to one-third is slashed by a digester.
Wisconsin currently boasts the most ADs of any state. 20 years ago, green energy prices were available for biogas-generated electricity. This is no longer an option in most parts of the country, hindering AD uptakes. Reinemann estimates only 5 to 10% of US dairies currently run a digester.
“They make a huge impact, but the main reason for a lack of adoption is they aren’t economically feasible on a small dairy especially when grazing is part of the feed management system,” he says. “Manure on grazing land can’t be collected. The technology is sound but unfortunately, it’s mostly larger farms capitalising.”
An extra benefit is digesters improve manure nutrient management as solids are separated from liquids making it easier to place nutrients where they’re needed most, addressing the N2O emissions from crop production.
Reinemann adds the biggest economic driver influencing digester adoptions is government energy policies. The upcoming federal election will likely impact this situation.
Looking north for inspiration
Dairies north of the US border have long been invested in on-farm sustainability practices for their future and the environment according to the Dairy Farmers of Canada (DFC) President, David Wiens.
“Over the years we’ve made great strides in reducing the emissions, land, and water required to produce each litre of milk, thanks to advances in agricultural technology and the sector’s ongoing commitment to continuous improvement,” Wiens says. “Dairy cows account for only about 1% of Canada’s total GHG emissions, and the carbon footprint of one litre of Canadian milk is less than half the global average.”
Thanks to innovations in herd management, genetics, feeding, and comfort, the Canadian dairy industry has become more efficient, helping lower its environmental footprint.
“The modern dairy-cow diet is more nutritious and often specially formulated to enhance digestion, which helps increase feed efficiency and milk production,” Wiens says. “It also reduces GHGs associated with methane animals naturally emit during rumination.”
Beyond nutrition, Canadian operations employ a variety of control practices. Innovations such as GPS-enabled smart tractors, on-farm data collection tools, robotic machinery, and other high-tech equipment support sustainable and efficient milk production. Crop rotations, manure management, cover crops, and decreased tillage also contribute.
Additionally, Canadian dairies are incorporating biodigesters to convert manure storage methane into reusable energy such as biogas and renewable natural gas, with the ability to use the manure by-product (digestate) as a natural fertiliser.
Likewise, genetics are accelerating sustainable and best management practices. Breeding cattle for climate resilience and lessening their environmental impact offers a vital opportunity for reduction. The University of Guelph Resilient Dairy Genome Project is researching and assessing new genomic evaluations to identify more feed-efficient, resilient to heat stress, and fertile cows with assistance from the DFC.
The Methane Efficiency genetic evaluation is a recent example of genetic advancements. It delivers the world’s first official genetic evaluation to help producers select for reduced methane emissions without impacting performance levels.
“Farmer’s livelihoods rely on the land, and sustainable practices help maintain their future,” Wiens says. “They’re proud of the care they give their cows and continuously work with experts to make the best choices about how their livestock live and eat, their health, and the traits they pass on. This increases productivity and demands fewer resources to produce milk while addressing emissions.”
Nutrition and technology boost reductions
Ermias Kebreab, Associate Dean, College of Agriculture and Environmental Sciences at UC Davis believes from a nutritional perspective, diet alone isn’t the answer as possible cuts only reach the 10 to 15% range.
“The big push of 40 to 60% can only be accomplished through additives and this is why many see them as the next big thing,” Kebreab says.
3-NOP, the most well-known methane-reducing additive, has recently been approved in the US and Canada. Rights-owner, Elanco, will use its vast technological roll-out experience to ensure a quick market impact.
Options like seaweed are also promising but still in the research and trial stages.
“Seaweed has presented some cultivation challenges,” he says. “We’ve much to learn about growing and storing it safely. Our work at UC Davis shows it to be effective up to 80% which is significant. If it’s found safe for animals, humans, and the planet, it will be a part of the solution.”
Genome editing technologies like CRISPR are similarly encouraging. A 7-year UC Davis trial is in the early stages of examining its capabilities.
“We’re trying to understand the microbiome better and identify what we can change and target,” Kebreab says. “We have the tools, but we need to learn more before we apply them and determine if it’s a viable solution.”
Incentives and market response
Kebreab agrees public pressure targeting livestock’s environmental impact is a key driving force for all endeavours. As more incentives are offered to meet agreed-on target numbers, the agricultural community will strive to build sustainability, ensuring farming isn’t harming the environment. Many players are currently attempting to meet their Paris Climate Agreement commitments.
He believes some influences will come from elected parties and officials, but most will be decided by the markets as many large companies such as Danone, Nestle, Starbucks, and McDonalds have already publicly committed to cutting emissions.
“I don’t think there is any way to back out of this now without ignoring their commitments and creating a negative reaction,” Kebreab says. “They’ll simply be forced to push ahead.”
He explains research and trial investments have been lacking although it is improving. Organisations such as the Global Methane Hub, the Gates Foundation, and increased USDA governmental funding are making a positive difference.
Looking to the future
Reinemann’s view of the future includes further reductions although he doesn’t envision ever reaching net zero. He sees anaerobic digesters becoming more commonplace, especially on larger farms.
“The efficiency of the dairy industry including emission management has strengthened,” Reinemann says. “This will likely continue as I think we’re on the verge of an agricultural technological revolution with automation, AI, and big data.”
Kebreab believes that with the technologies being developed worldwide, industry solutions will be near 25 to 50% reductions, which will be huge.
“There’s no silver bullet for this issue but the industry’s future is bright,” Kebreab says. “We’ll need to employ different methods as conditions demand with separate areas and regions having varying solutions, but we’re moving in the right direction. Many of these factors are business decisions but it’s happening faster than before. Much of it hinges on investments and economic incentives from world governments.”
References are available on request.
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