B+LNZ builds farm emission reduction toolbox | Beef + Lamb New Zealand
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B+LNZ Genetics

B+LNZ builds farm emission reduction toolbox

There is no single solution when it comes to reducing methane emissions on-farm, but Beef + lamb New Zealand is developing a suite of tools to help farmers manage their emissions.
Wednesday, 21 September 2022

In the first of a two-part series, we look at low methane genetics as a tool sheep farmers can start using now to help reduce their greenhouse gas emissions, without compromising productivity.

B+LNZ’s General Manager Farming Excellence Dan Brier, says rams with a breeding value (BV) for methane are now available to commercial farmers in a limited way and he is encouraging farmers to consider including low methane genetics in their selection criteria.

To date around 20,000 sheep in New Zealand have been tested for methane production and been allocated BVs for the trait.

Mr Brier says it is important other traits are not compromised when selecting for low methane genetics and research has found there to be no difference in growth rates between low and high emitting sheep.

Studies have shown that low emitting sheep grow slightly more wool, they are slightly leaner and more resistant to parasites. CT scans have shown that low methane sheep have rumens with smaller volume but have more dense papillae so have a similar surface area to the rumens of high emitting sheep.

Mr Brier says the outcomes of this research was reflected in on-farm performance on B+LNZ’s Future Farm at Lanercost.

Low methane rams and “normal” rams were mated to the farm’s commercial two-tooth ewes. The resulting ewe lambs were retained and mated as hoggets.

The performance of the low methane hoggets was compared with the untested hoggets in terms of growth and reproductive performance.

“Both lines performed exactly as expected based on their BVs. Both were similar in growth rates and the low methane sheep had better reproduction.”

Mr Brier says this study confirmed that BVs reflect real performance on-farm and this should give farmers confidence in using BVs as a selection tool.

The development of low methane genetics

Initial research on low methane genetics began nearly 20 years, but really got underway in 2007 when sheep in Central Progeny Tests were screened to find differences in methane production.

A four percent difference was discovered between high and low emitting animals and so began a comprehensive breeding programme, breeding low emitting ewes with low emitting rams and vice-versa to determine whether the difference between the low and high emitting animals was genetic or just an anomaly.

Sixteen years later, the two lines continue to diverge and there is now a 16 % difference between them.

Mr Brier says the heritability in methane production is 0.2 which is similar to heritability of growth rates and roughly double the heritability of reproductive traits.

He says the use of the Central Progeny Test animals was important because these are the sheep that have played in key role in the dramatic genetic improvement of the national flock over the past 30 years.

“These sheep have helped drive New Zealand’s efficiency gains in growth and reproduction. They are very well studied animals with genetics sourced from studs throughout the country.”

Mr Brier says this research is world leading and has been peer reviewed globally with a number of countries, including Ireland, the UK and Norway, now replicating what NZ scientists have done.

He says B+LNZ is undertaking work now to support accelerating the uptake of the technology through B+LNZ Genetics. This includes ensuring rams are available as soon as possible for farmers who want them. The organisation is also working on how farmers can get credit for using this technology in their GHG calculators and into the national inventory.

Next week we look at other mitigation tools under development including work on efficient farm systems.