Livestock – cattle and sheep mostly – the world over are being blamed for the high level of greenhouse gas emissions coming from agriculture and food production. Reducing consumption of red meat and switching to a plant-based diet might be one answer. But New Zealand – as a major global supplier of meat and dairy products – is exploring how it can cut methane emissions from agriculture in other productive ways. We asked one of our Contributing Editors, Environmental Scientist Brook Wright, to update us on this:

Low Carbon Livestock – A path to low emissions future?

By Brook Wright

There has much discussion on decarbonising agriculture in New Zealand. As a primary sector economy with a large agricultural base, it is no surprise that the carbon budget is dominated by organic emissions.

At over 40% of total, this is an area that needs drastic attention, particularly if New Zealand is to achieve its short and long-term mitigation targets. (https://www.mfe.govt.nz/climate-change/climate-change-and-government/emissions-reduction-targets/about-our-emissions).

Fortunately, there has been a significant amount of investment in this space and institutions such as AgResearch and Massey University are working towards creating pragmatic and future proof solutions. From discovering the heritability of low carbon genes to quantifying methane production in livestock, these are the innovations that are needed for creating farm ready solutions.

Some of the more promising developments have been made in the area of low GHG feeds. Earlier in 2019, red seaweed (Asparagopsis armata) was championed as low emissions supplement.

Research indicated that red seaweed, when fed in small amounts (~1% of food consumed) could limit enteric methane production by up to 60%.

If this could be practically used across the entire national dairy heard, New Zealand would meet its short term decarbonisation goals almost overnight [1]. However, further research has proved that this effect is short lived. As it turns out, Methanogens (methane producing microbes) are crafty little things and quickly adapt to alternate feeds.

To achieve lower emission in livestock it might be as simple as changing secondary feeds. While pasture (grass fed) beef is generally more desirable than grain fed beef from consumer standpoint, cereal feeds such as maize and barley improve conversion efficiency and reduce methane production.

Its estimated that pasture has a GHG intensity of 22.4g CH₄/kg/dry matter intake, while Radish and Fodderbeetfare much better at 11.4 and 13.2g/kg/dry matter intake. So, diet management might be the best current short-term solution for combating on farm emissions.

The selective breeding approach has garnered more media attention. New Zealand Beef and Lamb announced early this month that they had made available a breeding value (BV) tool to farmers for the assessment of GHG production in sheep.

This tool was created as part of a collaborative exercise by The Pastoral Greenhouse Gas Research Consortium (PGGRC), the New Zealand Agricultural Greenhouse Gas Research Centre (NZAGRC), and AgResearch, and represents more than 10 years of research and millions of dollars of investment.

Farmers can now evaluate their flocks using portable accumulation chambers and make decisions on which of their sheep are high emitters and which are not. The collection of this data is used to validate the BV value of Ram semen and improve selection decisions on farm (i.e. which Rams give the greatest chance of producing low carbon daughters).

These effects will not be felt immediately but considering the current flock numbers around 27 million, any small change will be compound. More data is needed though. And the magnitude of these selective decisions in mitigating enteric methane production is still uncertain.

This index will also need to prove its value in the sector and only time will tell whether famers will actively choose low carbon Ewes without any economic incentive to do so.

It is likely that low carbon feeds and methane BV values will form part of New Zealand’s mitigation response. These technologies are still novel and will take time to properly establish on farm. However, it’s clear that New Zealand and institutions are leading the way in creating a low carbon future.

1. Roque, B.M., et al., Inclusion of Asparagopsis armata in lactating dairy cows’ diet reduces enteric methane emission by over 50 percent. Journal of Cleaner Production, 2019. 234: p. 132-138.