Methane and cattle at NBRUC: No silver bullets but plenty of good science

This from CSIRO's team leader for northern livestock production Stuart Denman, who provided an overview on the journey to developing abatement technologies in Australia's ruminant livestock at the Northern Beef Research Update Conference in Darwin in late August.

Reducing enteric methane production will play a key role in the red meat industry's target to be carbon neutral by 2030.

A concern raised by producers was whether there was a risk of beef being thought of as genetically modified given the anti-methanogenic compounds being used in feed additives act on the rumen.

Dr Denman said the compounds in the products closest to market were not modifying the microbes in the rumen but rather inhibiting the pathway of methane production.

As such, there was no risk of being labelled a GMO food, he said.

Dr Denman explained there were supplements and additives that take direct action on methanogens - they inhibit pathways - and their impact on both the environment and the production system are known.

They work in a predictable way and have delivered up to 90 per cent methane reduction in intensive systems where they can be fed in a controlled way.

These include products like Bovaer 3-NOP, asparagopsis, plant extracts and inorganic salts.

"Then there are indirect acting inhibitors - the oils, polysaccharides and alginate and what they mainly do is reduce protozoa, which is the producer in the rumen of the feed source for methane," he said.

"Then we have legumes and forages, such as leucaena and desmanthus, which are less consistent in terms of the amount it reduces methane, but are more likely to provide productivity gains."

What will be critical as these feed products are rolled out is actually getting the dose into the animal, and getting the timing right, Dr Denman said.

"In grazing, we know there is individual variance in the uptake of these supplements," he said.

"The amount of supplement going in correlates with the amount of methane reduction."

Under current formulations, the product will only be in the rumen for a couple of hours.

"This explains why on a grazing diet we are seeing a 40 to 50 per cent methane reduction under controlled research conditions but when we go to a grazing system, it's only 15pc," Dr Deman said.

The inhibitors that reduce methane emissions disrupt the rumen microbiome, Dr Denman said.

"A rumen is set up to be efficient at converting grass into energy for the animal and methane is part of the equation," he said.

"So we need to look at ways such that if we are taking methane out of the equation, how do we shift it back to the productive rumen it was.

"There are ways to do that - we can provide other probiotics that mop up excess hydrogen and turn it into excess energy for the animal and preliminary scientific work is showing this is possible."

Other work happening on science's part is early-life intervention.

"We are looking at reducing methane in the first 100 days of life and then that leads to a lifelong effect," Dr Deman said.

"The results have been inconsistent so far but it's something to continue to look at in the background."

Reducing methane was the main focus of the investments Meat & Livestock Australia was making towards the CN30 goal, MLA's environmental sustainability manager Margaret Jewell told the conference.

"That's because the more we can reduce enteric methane production, the less we have to rely on carbon being stored in the landscape and the less we have to worry about the effects of building flock and herd sizes as seasons allow us to," she said.

The point was made by producers in the audience that carbon projects and the Australian carbon credit unit system rewards poor performers.

The more inefficient operators were now in a position to lift the efficiency of their herd, capture ACCUs and make money from the CN30 goal while those who were more progressive and had operated more efficiently won't see any financial reward but had done the heavy lifting for the industry.

Dr Jewell agreed there were producers all over the country who had been progressive and already adopted all the technologies available.

"However, what is just around the corner is being able to demonstrate your performance across a range of environmental sustainability indicators and those people will be at the forefront of that," she said.

"That demand is here already in some supply chains and much more is coming through - for example, the taskforce for climate related financial disclosures.

"So if someone is already doing all the best practice activities, the next thing to do is make sure you are measuring everything, you have a carbon account and you have the data, so that when it's asked of you, you are ready to go.

"There will be opportunity in being able to show you are performing at a higher level than the regional average.

"The United States Department of Agriculture already has a certification scheme for low carbon beef for those ranchers who can show their emissions intensity is 10pc lower than the national average."