5 Ways To Lower Cattle Methane Emissions
Cows are well on their way to becoming climate criminals alongside cars and aeroplanes. Livestock is being called out as a major cause of climate change more and more often, and methane emissions from cattle are an important part of the problem. Researchers are investigating several approaches that could help reduce these emissions - but how much of a difference can they really make?
A study carried out by the FAO (the Food and Agriculture Organization of the UN) makes it clear: livestock breeding accounts for 14.5% of all man-caused greenhouse gas emissions, with 65% of this attributable to cattle breeding. It is becoming clear beyond doubt that large-scale cattle breeding is a significant driver of the changing climate.
As our appetite for meat increases on a global scale, every day both the number of livestock and the urgency with which we must combat global warming are rising. Researchers are therefore exploring five key approaches to drastically reduce the methane emissions of our cattle herds.
1. Tinkering with the cow’s diet
One possibility to reduce methane emissions from cows is adjusting the balance of their feed: for instance by adding more corn. “Grass contains a lot of fibres, which cause hydrogen gas to be produced as they are broken down”, explains Dorien Van Wesemael from the Flanders Research Institute for Agriculture, Fisheries and Food (ILVO), who she examined the impact of feed composition and additives on reducing methane emissions from cattle as part of her PhD. “Microorganisms in the cow’s gut will then convert that hydrogen gas into methane.”
“The breakdown of starch from corn, on the other hand, consumes hydrogen gas. The right combination of grass and corn as feed, therefore, has the potential to reduce methane production - but it’s important to make sure that the cow’s wellbeing and production efficiency isn’t jeopardised. In terms of nutritional value, grass and corn aren’t just interchangeable.” Professor Theun Vellinga from the department Livestock and Environment at the Dutch Wageningen University agrees:
“There is a rather limited margin for change in terms of adjusting cattle feed. Feeding corn to cattle reduces methane emissions by 7 to 10%, but too much corn will result in an unbalanced diet.”
Plus, you have to look at the bigger picture. “Growing more corn would mean ploughing up pasture-land into fields, but doing so would cause that soil to release large amounts of CO2 currently stored in it. The benefit in terms of methane emissions is therefore lost. It would take 30 to 60 years to balance out those CO2 emissions from the soil with reduced methane emissions from cattle that are fed more corn.”
2. Adding supplements that slow down the production of methane
Another option is adding new supplements to cattle feed. Various experiments showed that adding seaweed to cattle feed produced drastic methane reductions: in experiments with artificial cow rumens, for instance, mixing red algae (Asparagopsis taxiformis) in the feed reduced methane production by more than 90%. But working with an artificial stomach is very different from an actual living cow, so for now adding red algae to cattle feed is still in its research stage. It remains unclear how it could be applied on a large scale and what the long-term effects would be.
ILVO is also investigating the effect of other feed additives besides seaweed. “The two most promising possibilities are flaxseed and an additive called 3NOP”, Dorien Van Wesemael explains. “Both work very differently. Flaxseed is a high-fat concentrate, and fat interferes with the breakdown of fibres in the rumen. Methane production decreases, but at the same time more undigested fibres will end up in the manure, which will start to ferment there, so it’s not clear yet how this would impact the methane given off by manure.”
“3NOP (3-Nitrooxypropanol), on the other hand, is a supplement that was specifically developed to slow down methane production. Experiments show that 3NOP yields a 20% to 30% reduction in methane emissions in both dairy and meat cattle without impacting production… but it’s a temporary effect, so if farmers stop administering 3NOP then methane emissions rise again.” The Dutch feed company Royal DSM is currently working to commercialise 3NOP in the near future.
3. Breeding climate-friendly cows
Not every cow belches out the same amount of methane, since the balance of microorganisms in the rumen differs from cow to cow. The entire composition of the bacterial community in the rumen is connected with the genetics of cows, which makes it possible to select cows that emit less methane, according to Professor Vellinga.
“There are considerable differences between cows in terms of methane emissions, and it looks very much as though these can be traced to the animal’s genetics,” Vellinga reports. “There’s lots of potential there. Thanks to advances in emission measurement technology and genetic sequencing. Currently, cattle are selected for breeding based on how productive they are, but now that the pressure’s rising to do something about greenhouse gas emissions, there’s also a growing interest to include their emissions in the breeding selection criteria.”
“With the genetic diversity we see, we can realize a 1% reduction in methane emission per year through selective breeding. If we keep this up long enough, I estimate a 20% reduction is quite feasible. Combined with other methods, this is definitely a promising lead.”
4. Capturing methane
No, not with a mouth mask and a gas tank - but by purifying the air in livestock stables to remove methane. The captured gas could even be utilized, for instance as an energy source; after all, one single cow emits enough methane to keep a pilot flame burning continuously.
“That is still a long way off though”, thinks Carel De Vries, Director of Courage, a Dutch organisation that initiates innovation projects in dairy farming. Together with the Delft University of Technology, Courage evaluated the feasibility of methane capture. “Our concept consisted of a biological filter for removing methane from the air in the stables using methane-eating bacteria. These bacteria convert methane into a kind of bacterial protein which could possibly be used as a fertilizer.”
The design encountered technical difficulties, de Vries recounts. “Since the air volume in a stable is quite large, such a biological filter would have to be almost as big as the stable in order to reach enough capacity. A second problem is that the methane concentration in the stable air is too low to make these methane-eating bacteria grow. Concentrating the methane first is an option, but that turned out to be too complicated and also just too expensive. Other systems, such as removing methane with filters or burning methane face the same obstacles.”
In capturing methane another problem presents itself: it’s only possible when the cattle are brought into the stables. When a cow is in the field, the emissions just evaporate, de Vries says.
“To make methane capture work, you would have to keep the cattle in the stables. And there we have a conflict between environmental purposes and animal welfare. We care very much about outdoor grazing, and cattle are already put inside enough as it is.”
5. Decreasing livestock numbers
A final approach in reducing methane emission is as simple as it is ‘loaded’: decreasing livestock numbers. Less cattle, less methane. Is it as simple as that? Perhaps not.
Decreasing livestock numbers indeed reduces greenhouse gas emissions and has a big impact on land use. But if this only happens locally and consumers keep eating the same amount of meat, the problem just gets shifted, Vellinga puts it. “As long as we keep consuming the same amounts of meat and dairy, they will be produced elsewhere. Adjusting livestock numbers isn’t necessarily pointless, but without reduced demand for meat and dairy it won’t make that much of a difference in terms of greenhouse gas emissions.”
Is there a quick solution?
Burping methane is not the only way in which cattle breeding contributes to global warming. Meat and feed transport, production of feedstuff, emission of other greenhouse gases, a surplus of manure… the list is extensive. But as the call to reduce the impact of cattle breeding, and by extension agriculture as a whole, grows louder and louder, reducing methane offers an opportunity.
Not all cattle herds have the same size environmental footprint. Read more about how beef herds can actually help regenerate the environment, and how low-impact producers reduce the environmental footprint of the meat they produce.
As demand for beef and dairy products keep rising globally, researchers are looking at reducing methane emissions as a fast solution to reduce the environmental impact of livestock. The only questions are how, by how much, and how quickly. “With what’s on the table now, a 10% reduction in methane emissions from cattle is feasible in the near future”, Vellinga says. “In the long run, I think selective cattle breeding combined with additives can cut methane emissions in half.”
But other than reducing consumers’ demand for beef and dairy products, “there is no miracle solution available”, cautions Nico Peiren from ILVO. “Research has provided a couple of possible approaches, but the results aren’t very clear. A short term 20 to 30% reduction is a very big gain already, but we mustn’t forget that a cow is a complex organism, not a machine - cattle will always emit methane. They are ruminants, after all.”
What do you think of these five approaches to lower cattle methane emissions? Let us know in the comments below!
The author originally wrote this piece in October 2018 for Belgian outlet Eos Tracé. Read the piece in Dutch here.