Consumers’ concept of clean labeling has expanded to include the environmental impact of foods and how they’re produced. But, are consumers ready for scientists to begin tampering with the ecological makeup of cows’ digestive system?
An article on BBC’s online forum (https://bbc.in/30gn9SF) titled “The Cows that Could Help Fight Climate Change,” by Geoff Watts, published August 7, 2019, presents a scientific study taking place at New Zealand’s farming science research institute—AgResearch, which is striving to reduce methane gas production from cows. Researchers developed a vaccine targeting methanogens, or those microbes that produce methane. The vaccine produces antibodies in the cows’ saliva and rumen that specifically target microbes that negatively affect the environment.
But how toxic is methane gas to the environment? “Methane is one of the most egregious of greenhouse gases, roughly 25 times more potent at trapping heat than carbon dioxide,” said Watts. In one estimate, livestock reportedly contributes “14% of all greenhouse emissions from human activity.” Aside from carbon dioxide and nitrous oxide, methane accounts for more than a third of emissions from agriculture. “The average ruminant produces 250-500 liters of methane a day,” adds Watts, mostly from burping, with a small amount coming from the other end. Globally, livestock emit the methane equivalent of “3.1 gigatons of carbon dioxide …annually.”
Methane gas is produced when the food cows and sheep eat ferments after being decomposed by anaerobic microbes, classified as archaea. This class of microbes account for approximately 3% of the total number of microbes found in the rumen of these animals.
Researcher Sinead Leahy, microbiologist at AgResearch and on secondary assignment to the New Zealand Agricultural Greenhouse Gas Research Center, used DNA sequencing to understand the role different microbes play in ruminant digestion. Leahy then used gene sequencing to develop a vaccine that produces antibodies specifically targeting methanogens.
To date, only a small number of animals have been given the vaccine. Measuring methane content involves placing the animal in a sealed respiratory chamber allowing only for fresh air flow. “Stale air” is measured for methane content. “But definitive proof that vaccination cuts the amount of methane belched out by cows is still lacking,” said Watts.
Several other methods of methane gas reduction from cows have been suggested. Eileen Wall, head of research at Scotland’s Rural College, explains that cows’ methane output varies, partly due to genetic differences She suggests that selective breeding could reduce methane gas, not in isolation, “but as part of a wider breeding program to develop healthier and more efficient sheep and cows—both these attributes also reduce the greenhouse gases generated per unit of meat and milk.”
Wall noted that the environmental footprint of milk and meat production has already dropped by 20% over the past 20 years. How this has occurred or been measured is not mentioned. But, Wall suggests that breeding lower methane producing cows would only reduce that statistic further. Yet, the downside of this method is that it could be costly and time consuming.
Other proposed methods of methane reduction involve altering the animals’ diet, so that food in the rumen is less prone to decomposition and fermentation via archaea microbes. Phil Garnsworthy, a specialist in dairy cow nutrition at the University of Nottingham, suggested that maize-based sileage might drop methane production by 10%.
Liam Sinclair, researcher of rumen metabolism at Harper Adams University, Shropshire, UK, suggested that legumes and oils such as linseed and soy oil could cut down on the fiber a cow eats, and thus the methane it produces.
Seaweed has also been suggested, as have additives like ionophores, which are classified as antibiotics and banned in the EU. Another additive, 3-nitrooxypropanol (3-NOP), could lower the efficiency of the chemical pathway archaea uses to convert carbon into methane, thereby reducing methane gas production by 30%, hopes the company that produces the additive, added Watts. Probiotics may be another option, but the delivery system is in question when animals feed on grass. And, my all-time favorite suggestion is “fitting cows with burp-collecting backpacks.”
What it all comes down to is this…regardless of the method used in the reduction of methane production, are consumers ready to eat dairy products or meat from cows with rumen that have been ecologically altered? Changing the type of feed might be the least manipulative method of reducing methane gas production from cows and sheep, but as a food scientist attuned to flavor manipulation, I wonder if some of the suggested feed changes might result in detectable flavor changes.
Those seeking clean labeled foods want products with minimal environmental impact, but will the tradeoffs such as vaccines for methanogen antibody production or genetic breeding be acceptable? Personally, I vote for the cow backpack methane gas collectors.
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