Wednesday, April 24, 2024

Sheep dosing promises methane cut

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NSW scientists are testing methods of getting stock to take their mitigation medicine.
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New Zealand farmers are not alone in facing the challenge of striving for value while mitigating their environmental footprint. Senior reporter Richard Rennie is in Australia to find out how our neighbours are approaching the issues of gene technology, carbon farming and sustainability.

Water dosing, pellets and feed additives are all options Australian researchers are considering when exploring ways to deliver methane mitigators to sheep.

Dr Julius van der Werf, head of animal genetics and production at the University of New England in Armidale, New South Wales, is co-ordinating four research groups across Australia.  

In Armidale they are trialling combinations of methane mitigators fed at varying frequencies and quantities to sheep.

In a controlled environment with respiration chambers, they have recorded up to 88% reduction in methane from sheep when fed Asparagopsis, or red seaweed extract. 

“We found feeding it twice a day gave a better, more consistent suppression [of methane]. When it was administered every two days, that dropped to only 50% reduction in methane emissions,” Van der Werf said.

In a grazing environment they have been using GreenFeeds chambers to administer a feed-based mitigator and to measure emissions. Methane reduction was lower in a paddock system, likely because not all sheep gain access to their full dose of feed additive. 

Groups in Western Australia have been trialling another compound, Agolin. This product is based on essential oil compounds and delivered reductions of 30%. 

The two compounds have significantly different cost profiles, with Agolin about 1cent a day, versus Asparagopsis at 15c a day.

“In light of the cost and reduction differences, our current proposal is to combine them or ‘stack’ the compounds,”  Van der Werf said.

It was Australian researchers at CSIRO who discovered the potential value of the Asparagopsis red seaweed, now developed through Future Feed. 

The company said the biggest challenge facing it is ramping up production to a level that will bring down the cost and make it more widely available.

While the reductions in methane emissions during the trials are encouraging, Van der Werf cautioned that commercial farm operations are likely to deliver significantly lower results.

“Despite that 80% in pens, we realistically think it will be nearer to 10-20% reduction at an industry-wide level, with lower levels of mitigation on the farm and considering adoption will not be complete.”

While not as significant, it is enough to make mitigators another tool to consider in the toolbox, he said. That will be alongside Australia’s rapidly advancing low-methane genetics programme, and research into alternate feed types.

Options for administration on farm could include dispensing it through the water system, pelletising it, or turning it into a stock lick.

“The best options are the ones where farmers are not having to invest a lot into infrastructure to deliver it.”

Australia’s targets for livestock methane reduction currently are not as enshrined as NZ’s 10% by 2030, and the Federal government is still to set definite reduction levels. 

Van der Werf said at present the main pressure points for reduction will come through supply chain and market demands.

He expects that within only two years early adopting farmers will be able to reach for a methane mitigator for sheep.

“And we expect it will be reasonably common to use it in five years.”

Work is also continuing to move the focus on Bovaer, the DSM mitigator, to be trialled on sheep.

Van der Werf also helped establish genomic selection in Australia’s sheep-breeding programmes and is working hard to apply that technology to achieve sustainable breeding goals, and to bring Australia’s low-emissions sheep genetic data into the national programme.

Essentially following NZ’s lead, his team are identifying low-emitting sires using methane measurement chambers, with growing demand from breeders to have their flock assessed.

Reducing methane intensity, or the amount of methane emitted per lamb produced, is the key metric they are working to. 

“Increasing productivity goes a long way to reduce methane intensity. If you go from one lamb per ewe to two, you would only need half the ewes to produce the same amount of lamb. 

“A balanced breeding programme might allow for some increase of the flock’s methane production by about 1%, but per kg lamb produced, it actually drops by more than 3% per year.”

He expects to have EBVs (estimated breeding values) for methane out by next year, based off testing of almost 10,000 sheep.

“Genetics will play a significant role in reduction of methane.

“If you did not develop the genetics, it would cost the sector about AU$500 million [$540m] a year, relying only upon feed additives.”

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