Air quality and cows

by Tamara Scully

Animal agriculture contributes to greenhouse gas (GHG) emissions. That is a fact. However, the contribution of livestock – all livestock animals, not just cows – contributes a mere 4% of the GHG emissions in the U.S. according to the EPA.

Dr. Frank Mitloehner of the Department of Animal Science, University of California Davis and Extension specialist in air quality, has been studying the impact of livestock on climate change for decades. Today, his research on feed additives to decrease methane emissions from cattle is making headlines. He has been featured on several podcasts, including Elanco’s “Rediscovering the Power of Healthy Animals” and Midwest Dairy’s “Dairy on the Air,” where he has discussed the contribution of cows to climate change, as well as solutions the industry has embraced and possibilities for the future.

Mitloehner and his colleagues at the UC-Davis Clear Center have been studying additives such as seaweed, essential oils and 3-Nitrooxypropanol (3-NOP) – a synthetic compound – in order to determine how the dairy and beef sectors can decrease their overall GHG contributions. In his recently published paper, the essential oil Agolin® Ruminant (AGO), which is a blend made from wild carrot extract, was shown to have reduced enteric emissions of dairy cows by 11% when used as a feed additive, fed at one gram per day to dairy cattle. The product is also used to enhance milk output and overall cow nutritional status.

During a recent podcast, Mitloehner explained that these additives “either change the rumen microbiology, the microbial composition of the rumen, or they change the enzymatic steps in the formulation of methane,” and by doing so, the amount of methane produced during rumen digestion is decreased.

All additives are currently in the experimental stages when it comes to methane reduction, he said. Within the next five years, however, he expects these methane-reducing additives to be readily available to producers.

Mitloehner sees enteric emissions reduction as a path forward for the cattle industries. While the focus has often been on manure management, controlling those cow burps – which emit more methane gas than does the manure – can reach segments of the industry where cows are grazing and not confined.

Methane from Both Ends

Cows do not cause anywhere near the GHG emissions of the industry, transportation and power generation sectors in the U.S., Mitloehner said. And the methane which ruminant animals naturally emit is not a long-term GHG: it dissipates over 10 years, unlike carbon dioxide and nitrous oxide, which last in the atmosphere for a very long time.

Even so, taking steps to make animal agriculture part of the solution, and create dairy and beef industries which are able to mitigate as many environmental concerns as possible, is a path forward and an important one to focus on, particularly in an atmosphere where “activist minorities claim to be a majority movement” and work to vilify cattle farming.

Manure management has previously been the primary focus of reducing methane in ruminant agriculture. Confined dairy operations have been incentivized to cover their manure lagoons (which are 98% water and 2% manure) and to capture the methane before it escapes into the atmosphere, ultimately burning it to generate power. Today, renewable natural gas (RNG) programs in California are helping farmers capture that methane for use as a vehicle fuel, and interest in such programs is spreading throughout the country.

As per Mitloehner, more than 100 California dairy farms now have anaerobic digesters and are capturing methane emissions, which has resulted in a 25% decrease in the state’s dairy methane emissions thus far. In another 10 years, he believes that through manure management programs, California’s dairy industry will reach a 40% reduction, which is the state’s goal by 2030.

The dairy industry in the U.S. has its own goal for reduction in overall GHG emissions of at least 25%. In 2020, DFA pledged to reduce direct and value chain GHG emissions 30% by 2030. According to Mitloehner, the dairy industry in America contributes a mere 2.2% of the nation’s total GHG emissions, as per the industry’s own life cycle assessment.

“We are taking this gas and emissions [and] turning it into fuel to replace diesel in vehicles,” Mitloehner said of the RNG programs in California. The goal is “a climate-neutral beef and dairy sector.”

But most of the beef industry, as well as grazing-based dairies, don’t have manure lagoons. While composting manure from feedlots or dairy barns also reduces the methane emitted, capturing methane from the other end of the cow can go a long way in making dairy and beef production less, well, gassy.

Enteric methane production requires fiber. Cows who are fed a high-fiber diet, like those grazing, do produce more methane per animal than cows in a feedlot setting, who generally are eating lower fiber feedstocks, Mitloehner said. That is part of the reason why it’s sometimes insinuated by those advocating for plant-based diets that even grass-fed beef and dairy are not environmentally-friendly.

But methane isn’t the only GHG which results from agricultural production of any type, and production of other GHGs occurs when growing and harvesting crops, both through the use of fossil fuels and the soil disturbances associated with growing these crops.

Feed additives offer a management technique which can reduce that enteric methane produced by grazing ruminants while potentially also enhancing cow health and milk production. These products, whether naturally-occurring as with seaweed, or synthetic as with 3-NOP, could offer dairy and beef farmers a means of doing good environmentally and possibly reaping the benefits through enhanced animal health and milk production.

Enteric methane emissions are “a larger portion than the manure part, and more difficult to control,” Mitloehner said. By controlling their production in the rumen, the beef and dairy industries can take a major leap forward in reducing their GHG footprint.

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