Methane production in ruminants is shouldering much of the load and part of the blame for agriculture in a world where carbon neutrality is a near-, mid-, and long-term goal to slow the planet's warming levels.
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Methane production occurs in the rumen, and according to the University of New England's Associate Professor of livestock production, Fran Cowley, this organ is a black box that contains many, many mysteries yet to be solved.
For example, a teaspoonful of fluid from a cow's rumen contains about one trillion organisms, with about 20 per cent yet to be scientifically identified and named.
Another fact is the rumen is one of nature's most efficient methane generators.
UNE has the world's largest installation of methane chambers, including 10 cattle respiration chambers and eight sheep chambers.
"These are the gold-standard approach to measuring methane," Professor Cowley said.
"We also have 28 green-feed units, which are an in-field methane measurement system.
"We are very proud that UNE has the largest capacity for methane measurement anywhere in the world. UNE established its methane research facilities with NSW DPI (Department of Primary Industries) in the late 2000s to 2010s."
Prof Cowley said while the UNE team were well aware of the global warming contribution of methane, the original investments were made in pursuit of more efficient cattle and sheep since expired methane is a loss of energy from the animal, and low methane animals theoretically should be more efficient.
Research into supplements to counter methane production has singled out an Australian seaweed, asparagopsis, which has been farmed with some success, and, in trials, has been found to reduce as much as 90pc per cent of rumen methane.
Asparagopsis is lauded as a potential means of cutting back methane in livestock production, and the key element Prof Cowley said is 3-Nitrooxypropanol (known as 3-NOP and sold as Bovaer by DSM) is not a synthetic bromoform, but an alternative to bromoform from seaweed.
She said 3-NOP has been under development for almost a decade. It is now the most commercially advanced methane inhibitor and is already used in commercial feedlots worldwide.
"The critical issue is that there are currently no products available commercially at your local produce supplier, for example, so we don't have retail prices available to us," Prof Cowley said.
"That said, many of the most effective products close to or at the point of commercialisation are expected to be sold in the range of $0.30 to $3 per head per day.
"To attain widespread adoption throughout the industry, our goal as researchers is to develop products that can effectively inhibit methane at around $0.03/head/day.
"However, most products have a dose-dependent response and the economic or productivity sweet spot for methane inhibition may not always be 100pc inhibition, and potentially a producer may be prepared to pay less for using less of an inhibitor because they are satisfied with a lower level of methane abatement."
Curious beef and dairy producers would have a key question for Prof Cowley: why is methane in the rumen in the first place?
"Great question," Prof Cowley said. "The rumen is a highly complex ecosystem consisting of trillions of microorganisms or rumen 'bugs' from thousands of different families. It's an ecosystem that is more diverse than the Amazon rainforest.
"Methane is produced by a family of microorganisms that survive by scavenging forms of energy that have been released from feed by yet other microorganisms, in the process of fermenting plant material in the rumen.
"As they digest these products of fermentation, hydrogen is extracted from carbohydrates, but it can't accumulate in the rumen, so methanogens attach four molecules of hydrogen to a spare carbon atom in the form of CH4 (methane), which the animal breathes off, clearing the rumen.
"Methane is a very simple molecular structure, and so it is the most effective way to deal with this accumulated hydrogen in the rumen."
Prof Cowley said the manner of production could select producer priorities within a herd. Rather than increasing herd numbers, improving the farm's sequestration ability could be an option.
"Producing more beef, milk or lamb from fewer animals is the best way to reduce emissions - essentially increasing production efficiency," she said.
"This can be achieved by improving animal health and nutrition so that pregnancy rates increase and weaning and turn-off weights increase for the same amount of time.
"Strategies to do this include improving the pasture feedbase, culling poor performers and reducing the animal health costs to productivity.
"If producers can achieve these herd productivity goals, they'll need fewer females for the same herd production rates for breeding herds and a shortened time to turn-off for growers, both of which will reduce their enterprise emissions while increasing their production efficiency.
"The question still remains 'what do producers do with the resources in land and pasture they have freed up by increasing production efficiency?
"With the right incentives, producers could put those resources to use for sequestration activities, for example, tree planting or biodiversity uses."