With global demand for milk and meat expected to continue rising in the next decade, U.S. dairy farmers have a great opportunity to fuel the needs of a growing population. To capitalize on this opportunity of growing demand, farmers also need to find methods for reducing dairy cow enteric methane emissions.

Francisco Peñagaricano, with the University of Wisconsin – Madison, believes selective breeding could provide practical and effective options for dairy farmers seeking to mitigate emissions from their future herds. 

Francisco Peñagaricano. Courtesy photo.

Peñagaricano is leading one of the research projects, awarded by the Greener Cattle Initiative (GCI) in 2023, to identify commercially feasible practices farmers can use to lower enteric methane emissions.

Here, Peñagaricano discusses the research project and explains how it could benefit U.S. dairy farmers and have a positive impact around the world.

Q. What is the aim of your research?

The primary goal of this research is to develop genetic tools so farmers can breed cows for lower methane emissions in the near term. All cows emit methane, but not every cow emits the same amount. Some cows release around 600 grams of methane per day, while others average around 300 grams. We need to first know how to identify the high- and low-emitting cows so then we can selectively breed for lower methane emissions.

Q. Is there anything else your project aims to achieve?

We also want to develop a low-cost, non-invasive milk test farmers can use to measure methane emissions. Imagine using the same milk spectrometry technology (mid-infrared spectra) that monitors monthly milk tests for quality, protein and fat to inform the herd’s methane emissions. Also, we are studying the ruminal microbiome of high- and low-emitting cows to understand how the microbiome composition and activity affects methane formation.

Q. Why is genetic selection such a powerful tool?

On average, today’s dairy cow produces more than twice as much milk than 60 years ago. In the last six years, 60% of that change in milk production is due to genetic selection.

So in the long term, genetic selection is a very powerful tool for achieving lasting gains in dairy cattle performance. Contrary to changes in nutrition, management or cow comfort, the changes achieved through genetic selection have three properties – they are permanent, cumulative and incremental. These properties make genetic selection very cost-effective.

Another exciting aspect is the global impact. The U.S. dairy industry exports more semen than it uses domestically. So the genetic selection tools developed in the U.S. would have a worldwide impact.

Q. What does the research measure?

The project aims to measure the amount of enteric methane emitted by individual lactating Holstein cows using the portable GreenFeed system, which captures air exhaled by a cow while eating. We then study the genetics of these cows to evaluate various traits, such as the daily quantity and intensity (per pound of energy-corrected milk) of methane emitted. Once these traits are better understood, we can begin to predict how selective breeding for cows can be used as a tool to manage enteric methane emissions in the future.

Q. What are the real-life benefits for dairy farmers?

If dairy farmers today want to breed cows for reduced enteric emissions, they do not have the cost-effective tools to do it. Our first objective is to develop a genetic evaluation for methane emissions, so farmers can look at a bull and know the genetic ability of its daughters to reduce methane emissions. U.S. dairy farmers never select for a single trait because multiple traits impact their profitability. The best tool for selective breeding is the economic selection index. The goal is to develop the national genetic evaluation for enteric methane emission traits and then implement them in the economic selection index, so dairy farmers can selectively breed animals for reduced methane along with the other economically important traits.

Also, if dairy farmers want to identify the cows within a pen that produce more methane, a quick and affordable tool does not exist. Imagine if milk buyers or the federal government were to incentivize dairy farmers to mitigate emissions. Farmers would need to know which cows emit more methane. Once high-emitting cows are identified, farmers could strategically apply nutrition and management-related mitigation practices. We want to help farmers identify high emitters using their monthly milk test results. We aim to use that technology to develop a prediction equation for methane emissions and work with milk labs to add methane emissions to milk test results along with protein, fat, lactose and somatic cell counts. That brings tremendous added value.

Q. How many cows will you study over a three-year period?

The three-year goal is to evaluate 4,000 Holstein cows in research farms, like the University of Madison – Wisconsin’s dairy research farms. These farms are as good as the best commercial operations. The only difference is we maintain very expensive measurement equipment and the managers allow us to put cows in small groups with consistent management, nutrition, cow comfort and milking periods for research purposes.

Research is underway in our 600-cow Arlington, Wisconsin, facility. We run eight-week trials with 64 mid-lactation cows between 50 days in milk (DIM) to 200 DIM. Each cow is measured for daily feed intake, daily methane emissions and daily milk production; milk composition four times per week; and bodyweight for beginning, middle and end of the trial. Another 32-cow pen is set up to resemble a commercial farm where daily methane emissions, but not daily feed intake, are measured.

Our Marshfield Agricultural Research Station, which raises replacement heifers and milks approximately 250 first-lactation cows, is conducting 32-cow trials in a pen that measures daily methane emissions with GreenFeed and feed intake using Calan gates. The Calan gate records each animal’s daily feed consumption.

Other collaborators are Michigan State University, Iowa State University, University of Florida and USDA-ARS U.S. Dairy Forage Research Center. All these collaborators are running trials with 45 to 65 mid-lactation cows each where they measure daily methane emissions and feed intake in each cow individually.

Q. What are the challenges in studying genetic traits for reduced methane?

The challenge is to develop the tools for measuring methane emissions in individual animals that characterize them and their ability to pass on the desired characteristic to their descendants. We are applying some of the same methods used in a large project to develop genetic selection tools for feed efficiency, also a very hard trait because you need to measure feed intake.

We begin by developing a reference population by measuring the methane emissions from each animal in a small group of cows. We also collect the genetic makeup of each animal. The goal is to develop a prediction equation based on the animal genomes. After we have the equation, traits can be predicted even in young candidates, for example, newborn Holsteins.

University research farms are measuring methane emissions in lactating cows and other economically important traits like feed intake, milk production, composition and bodyweight. Cows that produce more milk tend to eat more feed, are bigger and produce more methane. To create a trait for methane emissions, you must consider feed efficiency and impact on production. That is why we are also measuring production, composition and intake to create a trait for methane emissions that is adjusted for production.

Q. What preliminary findings are exciting to dairy farmers? 

I am excited about preliminary results shared at this summer’s ADSA Dairy Science meeting:

1. The positive correlation between feed efficiency and methane emissions means that the most feed-efficient cows tend to produce less methane. Conversely, less feed-efficient cows produce more methane. U.S. dairy producers are already selecting for feed efficiency, so technically they are already reducing methane emissions. Soon, we will have two sustainable genetic traits – feed efficiency and methane emissions. Producers will be able to select those traits at the same time with a positive correlation. 
2. The variability of methane production due to genetic effect is around 25%; milk production is 20%. Look at the dramatic changes we’ve made in milk production through genetic selection over the past 60 years. It’s reasonable to think we can accelerate progress in a trait to reduce methane through genetic selection.
3. The trait referred to as “residual methane emissions” – where methane production is adjusted by milk energy, bodyweight or intake – has a variability between 10% and 15%. There is still a lot of room for selection with that level of variability in this trait. 

Q. Do you see any research bottlenecks ahead?

The bottleneck is phenotyping or measuring methane emissions. While we are happy with the GreenFeed technology, it is expensive. And all the animal trials require human resources, which are also costly. Funding is the biggest challenge.

Another important bottleneck is knowledge-sharing. Building a knowledge base is critical. Ultimately, to best advise dairy farmers, trusted advisers and other industry stakeholders must understand the meaning of these measurements. We must build resource capacity for sharing information across the sector. 

Q. What will be required for future adoption?

If you ask dairy farmers what they want most from research, they will tell you to focus on science that is safe, affordable, realistic, productive and beneficial to the farm’s bottom line.

Dairy farming is a business. As such, it is driven by profit. In this country, the economic value of reducing methane emissions is yet unclear. So there must be an economic value for a methane emissions trait to be successful. It is the only way to implement it in the economic selection index.

Q. What must the industry understand about this research?

The dairy industry is under pressure. Society’s concern about animal welfare, food safety, environmental impact of farming, methane emissions and water quality highlights an obligation to address those concerns.

As a geneticist, I have a beautiful tool. Genetic selection is an extremely powerful tool to address society’s concern in terms of sustainable dairy farming – whether that is in selecting cows to be feed-efficient, low-methane, high-producing or healthier. We need to leverage its strengths.

The research project's purpose is to identify commercially feasible practices farmers can use to lower enteric methane emissions. Courtesy illustration.