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How can we impact enteric methane emissions from cattle?

Kate Cowles and Yan Sun for Progressive Dairy Published on 25 May 2021
Cows at the feedbunk

All economic sectors have an impact on global greenhouse gas (GHG) emissions. According to the Food and Agriculture Organization of the United Nations (FAO), agriculture accounts for 14% of global emissions.

Of that, dairy and beef farming account for a little under half (40%) of total agriculture emissions.

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If we examine further, the enteric GHG dairy and beef cattle produce most is methane (CH4). Stated by the Environmental Protection Agency (EPA), methane is 84 times more potent over a 20-year span compared to carbon dioxide (CO2). Conversely, methane sticks around for only about a dozen years while carbon dioxide can persist for thousands of years, steadily warming that whole time. This makes methane a target for short-term GHG mitigation and an opportunity to positively impact climate change.

In addition, consumer buying is dictating a change in our global food system as well are the commitments made by food producers, retailers and restaurants to positively impact the environment. Let’s take a look at what consumers are saying and make our way down the value-supply chain to see how retailers, restaurants, producers and animal feed producers are responding.

  • The HealthFocus International 2019 Global Topic Report claims 40% of global shoppers said “clean eating” has become more important in their diet over the last year. Clean eating is identified by consumers as: “What is good for the planet is also good for me.” It relies on four pillars: health, safety, trust and environmental impact.

  • Yale Program on Climate Change Communication (YPCCC) reports that one in four Americans say they have rewarded food companies that are taking steps to reduce their impact on the environment by buying their products at least once in the last 12 months. On the other hand, 21% of consumers will choose not to buy from a company that is not taking steps to reduce its environmental impact.

  • YPCCC also reported on Americans’ reasons for purchasing or eating plant-based foods (fruits, vegetables and meat/dairy alternatives). The majority say the following are “moderately” important to them: their health (91%), how food companies affect the environment (71%) and/or helping to reduce global warming (64%).

Beyond consumers, retailers and restaurants like McDonald’s and Starbucks, and food producers like Tyson, JBS and Marfrig, are receiving guidance and pressure from investors and shareholders to reduce their carbon footprint. Overall, the food system sees this as an opportunity to add value to their products, improve their brand image and promote sustainability.

Next up in the value-supply chain are dairy producers who provide the raw product for food producers. Dairy Management Inc. launched the Net Zero Initiative with 2050 stewardship goals, one of which is “To become carbon neutral or better.” Producers must decide whether and how they can reduce their carbon footprint while still making a profit. The last part, “still making a profit,” is the biggest challenge to date and requires producers to research, learn and utilize existing and future technologies.

One level above producers in the value-supply chain are animal feed producers. These companies work directly with producers providing consultation and expertise on farm management, nutrition programs and animal feed products. Many dairy producers rely on feed companies to provide education and resources to benefit their operations. And some of these companies have their own sustainability commitments. For example, Cargill has a goal to reduce absolute GHG emissions in its operations by a minimum of 10% by 2025, against our 2017 baseline.

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Strategies for reducing methane

There is currently no silver bullet to reduce enteric methane emission while still maintaining a profitable farm. Multiple factors must be considered – breed of cattle, how much milk or meat they yield, farmer care, feed and nutrition programs, as well as geography and available resources like time, financials and people.

If we take a step back and assess it globally, we can see that it is not a one-size-fits-all solution. Farms within Asia overall have low production levels and feed efficiency. These farmers may find improvement of genetics, farm management and nutrition programs to be the main area of focus, while farmers in North America and Europe may focus on rumen modifier solutions, since cattle genetics and best management practices are mostly implemented.

To measure enteric methane emissions, the meat and milk yield of each animal must be considered. Using CH4 per pound of milk or meat will accurately measure an animal’s efficiency and production. It is clear how ruminants produce methane and that lessening their production is possible. What is crucial is utilizing these proven strategies.

1. Genetic approaches that promote productivity – Reduced enteric methane emission and improved ruminant productivity go hand in hand. Since 2009, the genome sequence of cows has been known and used to advance the species’ efficiency. Genetic selection is increasingly being used to expand the rate of genetic progress for production traits (i.e., milk, meat yield and quality). This strategy reduces both enteric and manure CH4 production and offers farmers an opportunity for both continuous and permanent improvement.

2. On-farm management practices that increase average production per animal – Refining how we take care of our animals is the most valuable strategy for farmers because it has the greatest impact while potentially costing the least amount of money. By heightening the herd’s productivity, enteric methane production per pound of milk or meat is reduced.

Best practices can include:

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  • Increasing the average age of lactating dairy cows on a farm. This increases the number of older cows, who are often the highest milk producers on a farm.

  • Reducing stress to the animal by ensuring a ventilated and comfortable environment for living, gentle handling and interactions between humans and cattle, as well as space and freedom.

  • Using technology and knowledge to breed cattle at the optimal time so they reach their highest production potential.

3. Improved animal productivity through feeds, feeding management and nutrition – Raising animal productivity through feeding has two parts:

  • Part one relates to rations cattle are offered. High-quality feeds and forages are more digestible and could improve production of milk and meat. Feed additive products – such as essential micronutrients, probiotics and antioxidants – can boost intake, digestibility, health and productivity.

  • Part two relates to how cattle feeds are prepared and fed by the farmer. For example, finer grains that are cracked or ground and have smaller feed particle sizes are easier for digestion. Farmers likewise need access to feed lab analyses, manure testing, a precise and accurate diet formulation system, and on-farm trials to monitor the effect of the current diet on animal performance and to ensure optimal feed efficiency.

Feed is the greatest expense for farmers, so implementation of this strategy must be balanced with current economics. Because a cow’s diet and intake highly affect how feed is digested in the rumen, as well as the health of its microbes, focusing on nutrition and feeding management can have a significant impact on reducing methane.

4. Rumen modifiers – Additives like rumen modifiers can directly reduce methane emissions. Remember methanogens – methane-producing microbes? Some rumen modifiers can work to directly inhibit the growth or function of methanogens; others can limit how much H2 and CO2 are available in the rumen, which reduces CH4 production. Research in this area included the possibility of introducing new microbes into a cow’s rumen that use enteric methane and turn it into usable nutrients for the cow, reducing the amount expelled by cows into the atmosphere.

Some modifiers can promote the creation of different nutrients. For example, volatile fatty acids, acetate, propionate and butyrate are nutrients created by microbe fermentation. A byproduct of acetate production is H2, while propionate uses available H2 for its creation. Modifiers can promote production of propionate while inhibiting acetate to reduce H2 for methane synthesis.

Through the use of these strategies – combined or individualized – reductions of up to 30% of methane per unit of animal product can be achieved, without significantly negatively affecting the amount of milk or meat the animal produces. This is based on the invited review: Enteric methane in dairy cattle production: Quantifying the opportunities and impact of reducing emissions.

Although these changes may sound simple, we must remember that implementation requires research and financial investment by producers. Dairy producers ultimately take on the capital risks of raising and feeding livestock, along with the fluctuations of milk and feed markets. Therefore, economic benefit for the farm needs to be considered when implementing methane-mitigating strategies.

Providing incentives and monetary value could help alleviate some of these risks and accelerate progress in reducing agriculture’s environmental impact. Dairy producers have access to the resources, knowledge and technology to get started. However, for industry-wide CH4 reduction, many new technologies still need support for research and hopefully adoption by dairy producers. end mark

PHOTO: Staff photo.

Yan Sun is the global methane reduction program lead for Cargill. Email Yan Sun

Kate Cowles
  • Kate Cowles

  • Dairy Innovation Lead
  • Cargill
  • Email Kate Cowles

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