You could grow old searching for the silver bullet solution that reduces methane production from grazing cattle. Kathy Soder doesn’t believe one single solution exists, but she believes it is possible to make improvements through research and by keeping an eye on the big picture.

“Grazing ruminants do produce more methane per day, and sometimes per unit of output, than in confinement systems — that is just fact,” says Soder, a researcher with the USDA Agricultural Research Service Pasture Systems and Watershed Management Research Unit in State College, Pa. “However, greenhouse gas emissions by ruminants is only part of the carbon footprint story.”

Any proper analysis of the impact of livestock, particularly cattle in grazing systems, must include a total life cycle assessment of all the ways animals and the environment interact, she explains. “You must give credit for the value of sequestering carbon in the soil in pastures,” she says. “It can’t be a ‘we versus them’ comparison either. You can make improvements in any system, including grazing and confinement for dairy cattle.”

Confusion about methane emissions

Most sources agree that about 14% of global gas emissions come from ruminants. Nearly half happens in grazing systems. Beyond these two assertions, there are more questions and confusion than hard facts about how to reduce methane emissions.

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“That’s why we don’t have solid recommendations,” Soder says. “We know several areas where we should be able to make improvements, but we can’t zero in on how much improvement can be made.”

Grazing research on emissions with moving animals is difficult, with a lack of recognized measurement standards. Some researchers report methane production in grams per day; others as yield in grams per kilogram of dry matter intake; and yet others as methane intensity, measured in grams per kilogram of milk produced or pounds of gain per day in beef cattle.

“Some studies, for example, show that a potential additive reduces methane intensity,” Soder explains. “But that is only because it increases milk production, diluting the same amount of methane produced per day over more pounds of milk. You must understand how results are reported.”

Seeking improvements in cattle

Here are six areas where Soder and others see potential for increasing efficiency and reducing methane emissions:

1. Optimize age at first calving and reduce calving intervals. “Let’s get them calved and milking, rebred and going forward,” Soder says, adding that cows in dairy or beef herds producing methane without carrying their share of the load are dead weight.

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2. Increase production per cow. In dairy cattle, that means increasing milk production. In a beef herd, it means a higher average daily gain. It is all about overall herd efficiency, Soder says. Look for ways to produce more while animals are producing the same amount of methane.

3. Manage grazing better. “No matter what you’re doing now, there are always ways to improve grazing efficiency,” Soder says.

For example, one research study indicated that switching to rotational or intensive grazing reduced methane production by over 20%. Another study indicated shifting to improved pasture with higher-quality forages reduced methane by over 25%. And feeding grass haylage vs. dry hay dropped methane emissions 12%.

“Sometimes these studies are done in vitro with machines that simulate the rumen,” Soder notes. “We need to repeat it in live animals over time.”

4. Improve forage quality and diversity. There are indications that forage brassicas, like those used as cover crops today, can reduce methane. One study looked at using forage canola to drop methane levels.

“We replaced two-thirds of the baleage for cows grazing canola forage at night,” Soder explains. “Dry matter intake went up by 5% and methane production went down 15%. But milk production dropped 5% to 7%. So, you must weigh trade-offs.”

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5. Consider supplements and feed additives. Red seaweed has attracted the attention of dairy and beef producers as an additive that could reduce methane. Fischer Farms, Dubois County, Ind, is in the middle of a USDA Climate-Smart grant aimed at learning how to produce beef in a carbon-neutral system. Unable to obtain red seaweed, Dave Fischer tried brown seaweed. He reported some improvement in lower methane emissions.

At the University of California, Davis, Ermias Kebreab and associates set up a grazing trial with 24 beef steers at the Matador Ranch in Dillon, Mont. Half the cattle had access to a supplement containing Brominata, a supplement made from red seaweed, Asparagopsis taxiformis. The other half of the steers could not access the supplement. Methane emissions were nearly 40% lower in the group with access to the seaweed supplement.

The study was published this month in the Proceedings of the National Academy of Sciences. Kebreab believes the work shows it could be possible to make a seaweed supplement for grazing animals, perhaps even allowing ranchers to introduce seaweed through a lick block.

Still, Soder has questions and concerns, based on their own in vitro studies. “We found that methane emissions decreased 98%, but digestibility also decreased,” she reports.

Plus, there could be handling and accessibility issues. Currently, wild red seaweed is harvested in small amounts and should be stored in the dark. Soder’s work showed that the chief ingredient, bromoform, varies greatly with the source of seaweed. It also degrades significantly over time.

6. Improve feed efficiency through genetics, nutrition and management. Selecting for cattle with rumen biomes less favorable to methane production may be possible.

“We experimented with supplementing with flaxseed with some success, and other research shows that fats can reduce methane emissions,” Soder says. “However, there can be negative effects that come along with these methods. We need to keep asking questions, always striving to improve overall management.”