Burps of doom
When cows belch, they emit methane, a potent greenhouse gas. some scientists are investigating whether their fodder makes a difference. Others are testing new ways to make cattle farming more climate-friendly.
WHEN cow number 121 belches, scientist Elisabeth Gerster takes a very close look at her lunch.
The dairy cow is part of farmer Gerold Mohr’s herd. When she’s given concentrated feed, scientists measure how much methane the cow produces later.
Farmers and agricultural experts are working on feed strategies to help slash methane emissions, a potent and harmful greenhouse gas.
Cutting farming-related methane emissions would be key in the battle against climate change, according to an assessment from the United Nations Environment Programme (UNEP) and the Climate and Clean Air Coalition last year.
“Connections between feed and methane emissions have been known for a long time,” says Gerster, a specialist at a German agricultural centre. What she and her team want to see is the effect of different feed in practice.
So in southern Germany, Mohr and his wife Beate feed the herd grass and hay, then the scientists spend the next two months analysing how the cows digest it.
Mohr’s farm is one of four in the region involved in the project. What he wants is for people to realise that in themselves, cows are not responsible for global warming and don’t deserve to be seen as “climate killers”, something he’s heard people say.
Holistic pasture management
In Bavaria, farmer Tobias Heiligensetzer is taking a different approach, allowing his herd to graze in a particular way in the hopes that will cut emissions.
Heiligensetzer, an organic farmer, ensures his 50 dairy cows only graze in the same area for short periods of time, then gives the grass some time to recover.
That involves him spending an hour-and-a-half each day putting up new fences, with the aim of protecting and improving the soil and grass, in an approach known as holistic pasture management.
He and seven other small farms are trying out the approach as part of a project that’s run with the Bavarian conservation academy and Munich’s Technical University.
The approach is already succeeding, says Heiligensetzer who has noticed his pastures are more productive, the cows provide more milk, and he is seeing more biodiversity on his 52ha holding.
It’s paying off, he says. “Economically, things have never been better than they are now.”
More humus on the pastures and higher growing grass stores more CO2.
“After all, humans take advantage of the fact that the cow makes grass usable,” he says.
Heiligensetzer says this is the only way food can be produced on grassland, and grassland has a better climate balance than arable land as it stores CO2.
So farmers should rely on grassland fodder, as grasslands are a very important store of carbon, says Bjorn Kuhla, an expert on nutritional physiology and farm animal biology.
Cattle farming can be made climate neutral, if cows don’t eat more from the grassland than is able to grow back on the same area in the long term, he says.
The methane that the animals emit is broken down into CO2 within 12 to 13 years, Kuhla explains. Then it can be completely reabsorbed by plants, a cycle that was intact up until the 18th century.
There are further ways to make cattle farming more climate-friendly, according to Kuhla. He suggests dual-purpose breeds that can provide milk and meat, as long as that’s accompanied by a fall in the number of pure beef cattle.
Using the methane?
Scientists are also working on whether it would be possible to capture and purify the methane belches that cows produce, in the hopes of using it to fuel agricultural machinery.
“If this succeeds, even more material cycles could be generated in agriculture,” says Kuhla.
Some of these approaches conflict with each other, however, says Gerster.
Grass and hay, for example, have a better carbon balance in cultivation but when cows digest the fodder, they produce more methane than with concentrated feed.
“More concentrated feed also means you need more grain,” says Michael Asse, who works with Gerster, pointing out that every additional hectare of arable land used to grow feed grain is then no longer available to produce food.
So far, Gerster’s team has only found that different feedstuff reduce cows’ methane emissions by about 3%. Hopes now rest on feed types that have not yet been tested, such as red clover and sainfoin, a perennial legume.
“Maybe there will be another opening for one or the other plant,” says Gerster, adding that farmers could then be encouraged to grow them through subsidies.
Cow 121, meanwhile, is still munching away on the grass. Farmer Mohr feeds around 10 tons a day to his 80 or so cows, enabling him to largely do without concentrated feed.
Mohr still wants people to understand that his cows don’t deserve to be seen as climate killers and Kuhla agrees.
While cows emit more climate-damaging gases than other farm animals, they are not competing with people for food, “if you feed them sensibly”.
The animals themselves are not the problem, Kuhla says. “Cows do much better than humans in terms of their carbon footprint.” – dpa