The Cows Who May Be Able To Aid In The Fight Against Climate Change

5th June, 2021.      //   Climate Change  // 

The stinky body functions of animals account for a significant portion of global greenhouse gas emissions. Can messing with their gut microorganisms aid in the fight against climate change?

The cows grazing happily at AgResearch, New Zealand’s farming science research institute, appear like any other. They walk about the pastures with their heads lowered, tearing up mouthfuls of grass and letting forth gentle, low moos.

However, some of these cattle are not the same as those found on other ranches. An experiment that could potentially change the world is taking done behind the scenes, inside the hardworking stomachs of these cows.

They were given a vaccination to protect them from particular gut microorganisms that produce methane while the animals digest their meal. Methane is one of the most severe greenhouse gases, with a heat-trapping capacity nearly 25 times that of carbon dioxide.

The goal of AgResearch is to create this vaccination, as well as other anti-methane technologies, so that we can continue to eat meat and dairy products while reducing the environmental impact of the cattle business. You could say that beef is guilt-free, and cheese is guilt-free.

Estimates vary, but cattle is thought to be responsible for up to 14% of all human-caused greenhouse gas emissions. Aside from carbon dioxide, farming produces enormous amounts of nitrous oxide and methane from the addition of fertilizers and wastes to the soil.

Burping (and a minor amount from farting) the methane equivalent of 3.1 gigatonnes of carbon dioxide into the atmosphere is a global problem caused by animals.

However, AgResearch scientists believe it may be able to lessen cattle farming’s contribution to global warming.

Ruminants produce about 3% of the total amount of methane produced by the enormous number of bacteria that live in the rumen.

Their method was created by Sinead Leahy, a microbiologist at AgResearch who is currently on secondment at the New Zealand Agricultural Greenhouse Gas Research Centre.

These microorganisms degrade and ferment the plant materials consumed by the animals, releasing methane as a byproduct, in a process known as enteric fermentation. The animals burp it out to relieve the pressure that can build up while the gas is created.

However, Leahy and her colleagues had to figure out a technique to replicate the rumen’s oxygen-free conditions in their lab in order to locate the bacteria responsible. They were then able to sequence the genomes of some of the major species using DNA technology.

“Knowing what distinguishes these microorganisms from other types that are similarly vital for ruminant digestion is critical,” Leahy says. “Through our research, we were able to examine across different sorts of gene sequence [in bacteria] and identify targets that were [similar] across all methanogen variations. These became the most important targets for vaccine development.”

As a result of this approach, AgResearch’s team was able to develop immunizations that targeted many microbe species at the same time.

Livestock is responsible for releasing the methane equivalent of 3.1 gigatonnes of CO2 into the atmosphere every year.

“In the subset of archaea we’ve tried to target, there are around 12 or 15 species,” says Peter Janssen, chief investigator of AgResearch’s methane mitigation program, who has found various methane-producing microorganisms in the rumen of sheep and cows. The vaccine, which is administered by injection, is designed to increase the production of anti-archaea antibodies in the animals’ saliva, which is subsequently transferred into the rumen as they swallow.

The AgResearch team has only given the vaccine to a small number of cows and sheep in trials so far. However, the study discovered a high level of antibody in the saliva as well as the rumen, and antibodies were also found in the feces. According to the Pastoral Greenhouse Gas Research Consortium, which has been the primary funder of the study since 2006. They’re now trying to show that the antibody produced by vaccinated animals actually prevents methane generation.

Animals must spend time in a respiratory chamber, which is a huge transparent box with only a flow of fresh air. The methane content of stale air leaving the box is measured.

In order to better duplicate what happens in the wild, the researchers are also attempting to take measurements outside of the lab. A customized feeding bowl into which the animal must place its head to eat is one method. “A gadget inside the feeding trough can sample their breath while their noses are in it,” Janssen explains. A device that can be fastened on an animal’s back is even more ingenious. “It has a small plastic tube that ends just above the animal’s nose,” says the narrator.

There is still no solid proof that vaccinating cows lessens the amount of methane they produce.

Neither methodology compares to the respiration chamber in terms of precision, but they both give a good indication of what’s going on in big groups of animals. However, conclusive evidence that immunization reduces the quantity of methane emitted by cows is still missing.

Janssen and his colleagues know that inhibiting methanogens results in the expected reduction based on past work with medicines. But Janssen and Leahy aren’t the first to try to develop a vaccination against methanogens, which are microbes that produce methane. In the 1990s, some Australian scientists tried, but were unsuccessful. The AgResearch team is sure that their genetically informed strategy would produce greater results.

Vaccination, though, isn’t the only option for clearing up cows’ breath. Animals produce different amounts of methane, and some of this diversity can be attributed to genetic variances. This allows for selective breeding for animals that release less methane, according to Eileen Wall, head of research at Scotland’s Rural College. She sees this as part of a larger breeding program to make healthier and more efficient sheep and cows, both of which cut greenhouse gas emissions per unit of meat and milk produced.

“We’ve already decreased the environmental footprint of milk and meat production in the UK by 20% in the last 20 years,” she claims. Low-methane breeding would simply be an add-on to existing programs. She and her coworkers are experimenting with several ways to accomplish this.

The more fiber a cow consumes, the more methane it produces, however supplementing their diet with legumes and different oils can assist.

Not everyone is that sure of themselves. According to Liam Sinclair, a rumen metabolism researcher at Harper Adams University in Shropshire, UK, breeding animals in this manner could be time-consuming and costly.

Another option is to offer animals a diet that is less appealing to archaea. According to Phil Garnsworthy, a dairy cow nutritionist at the University of Nottingham, this can be partially effective as long as the animals can continue to produce milk and meat.

“By changing your diet, you can probably lower methane by roughly 20-25 percent,” he explains. According to one study conducted by experts at the University of California, Davis, modifying cows’ diet might reduce global methane emissions by 15%. Garnsworthy, on the other hand, believes that more could be done. Farmers in the United Kingdom, he claims, mostly utilize grass-based silage.

“If you merely switched to maize-based silage, you might notice a 10% reduction in methane production.” The more fiber a cow eats, the more methane it produces, although Sinclair says that adding legumes and other oils like linseed and soya to their diet can assist. According to him, “better quality nutrition makes animals more productive, and more productive animals emit less methane.”

Fitting cows with burp-collecting backpacks is one slightly wackier approach that has been proposed.

The addition of seaweed to a cow’s diet has also been demonstrated to help the bugs that produce methane.

Fitting cows with burp-collecting backpacks is one proposal, while students at the Royal College of Art in London have created a gadget that might be connected to a cow’s nose ring to convert breathed methane into less potent, but longer-lasting carbon dioxide.

Feed additives like ionophores, which are already used in some regions of the world to increase animal weight increase and may also be used to prevent methane-producing archaea, are a more feasible alternative. However, they are not without flaws.

Ionophores, which are antibiotics, are prohibited in the European Union for use in animals due to concerns that their overuse in agriculture has aided in the development of drug resistance in bacteria. Ionophores are not utilized in human medicine and function in a different way than medicinal antibiotics, hence the restriction is contentious.

Other additives are available that may aid in the reduction of methane in livestock. 3-nitrooxypropanol (3-NOP), which acts by reducing the effectiveness of the chemical pathway by which archaea convert carbon to methane, has recently sparked interest. The additive’s creators are hoping for a 30 percent reduction.

Giving cattle probiotics, or beneficial microorganisms, to improve digestion is another possibility. Elizabeth Latham, a former Texas A&M University researcher and co-founder of Bezoar Laboratories, has been working on a probiotic to combat methane emissions from cattle, claiming that it can lower emissions by 50%.

Chemical inhibitors and probiotics, on the other hand, would have to be added to feedstuffs on a daily basis, and would be difficult to administer to animals that eat largely grass. It will almost certainly be a costly alternative. It’s possible that a vaccination might only need to be given once, or that an annual booster would suffice.

Changing the pattern of microbial life in the gut, regardless of the method utilized, would affect its ecosystem — possibly with unintended repercussions. The gut microbiome is intimately related to health and altering it can raise illness risk. Gut bacteria and mood have been linked in humans, but it’s unknown whether lowering methane-producing bacteria would result in depressed cows and sheep, or what effect this would have on their meat and milk.

It’s doubtful, according to Janssen. He continues, “We don’t get any signals that we’re going to stop animals from turning grass into meat or milk.”

However, the world will have to wait with baited breath until more tests show that editing livestock stomachs can reduce emissions without harming the animals or the items they are farmed for.