Methane research has been a hot topic in the beef industry. During the recent Beef Improvement Federation (BIF) Symposium, multiple presentations focused on methane research on how to reduce emissions, its link to feed efficiency and how genetic improvement could be possible.
This is the first article in a series that will breakdown what methane is and its impact on the environment.
What is Methane?
Methane is a greenhouse gas. Cattle produce methane through enteric fermentation, a natural digestive process that occurs in the rumen. It’s created when methanogens (a type of archaea microbe) in the rumen microbiome convert hydrogen and carbon dioxide into methane during feed digestion.
According to the “Beef’s Role in Greenhouse Gas Emissions” website, the biogenic carbon cycle is a naturally occurring process where carbon is utilized, recycled and stored in different states. In nature, plants take in sunlight and carbon dioxide and use them to create carbohydrates in a process called photosynthesis. Cattle then eat the plants and digest the carbon that is stored in the plants, undergoing enteric fermentation.
Cattle are ruminant animals, meaning that microbes in their stomach breakdown carbohydrates through the fermentation process. Ruminant animals, including sheep, goats, buffalo, elk and deer, have a unique four compartment stomach to help break down food. The rumen is the largest of these four compartments, filled with microorganisms that help break down foliage like grass.
This process creates gasses such as methane. This methane is then belched out — not through flatulence. After approximately 10 years, methane is broken down in the atmosphere and converted back to carbon dioxide which plants can take in, thereby completing the carbon cycle.
During a Beef Cattle Institute (BCI) “Diving into Diets” podcast, Brad White, Kansas State University veterinarian, and Phillip Lancaster, K-State BCI nutritionist, discussed how methane is created along with mitigation strategies.
Lancaster says methane is produced anytime there is anaerobic fermentation. When organic materials, like feeds, is being broken down by microbes with a lack of oxygen. He says large sources of methane produced by agriculture related causes include the enteric fermentation in ruminant animals, lagoons and rice paddies.
He adds non-agriculture sources are wetlands and landfills. According to Lancaster, it is about a 50/50 split for methane production between ag- versus non-ag-related sources. In the beef industry, two primary sources of methane are enteric fermentation (digestive processes) and manure management systems.
Lancaster says cows on grass produce more methane than feedlot cattle.
“It’s the cows out on grass that are producing three-quarters of the methane that the whole beef industry produces,” he says.
With forages, because of the slower rate of digestion — and the lower the quality of the forage equates to slower the rate of digestion, a higher proportion of that original energy being emitted as methane. In comparison with feedlot cattle on a high-grain diet, because of the rapid rate of digestion and the type of end products, there is a much lower proportion being emitted as methane.
Do Cattle Cause Global Warning?
Media has placed a lot of blame of the changing climate on cattle. Scientific evidence does not support this claim in the U.S. In the “Tough Questions About Beef Sustainability: Are U.S. Cattle Causing an Increase in Global Warming?” fact sheet, it reports that methane has a relatively short atmospheric lifespan, unlike carbon dioxide, which can remain in the atmosphere for hundreds to thousands of years.
This characteristic makes it an attractive target for rapid climate change mitigation. The methane produced by cattle is part of a natural carbon cycle, where plants absorb carbon dioxide and animals release it, unlike fossil fuel emissions that introduce new carbon into the system.
According to BeefResearch.org, between 1961 and 2019 the U.S. beef industry, through continued sustainability efforts and improved resource use, has reduced emissions per pound of beef produced by more than 40% while also producing more than 67% more beef per animal. Emissions from cattle, including those that come from the feed production, fuel and electricity, account for 3.7% of the total greenhouse gas emissions in the U.S.
Currently, emissions from U.S. beef cattle are less than 0.5% of the world’s greenhouse gas emissions. In fact, emissions from beef cattle represent 2.2% of total U.S. greenhouse gas emissions. These numbers will likely continue to decrease as farmers and ranchers seek to reduce methane emissions further through best management practices, including grazing management and feed supplementation.
Comparing the emissions from cattle to those emitted by vehicles through the combustion of fossil fuels, both affect the blanket around our planet. However, there is a major difference between these two sources of greenhouse gases. Burning fossil fuels takes carbon that has been stored in the earth since pre-historic times and converts it to carbon dioxide released to the atmosphere.
Methane Research is Not New
Lancaster says early methane research was done back in the early 1900s because it’s a loss of energy during the feed digestion process — it’s energy the animal does not get to capture and utilize.
“We know a lot about enteric methane production, because we’ve been studying it for 100 years,” he explain.
White and Lancaster summarize methane reduction in the beef industry requires a multifaceted approach. Continued research, innovative technologies and an understanding of the carbon cycle will be essential in developing effective, economically viable solutions that support both environmental sustainability and agricultural productivity.
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