New technologies transforming sheep methane measurements

Ireland’s climate change targets are well documented, with lofty targets in the last Programme for Government and Climate Action Plan aiming to halve our greenhouse gas (GHG) emissions by 2030 and reach net zero by 20250 at the latest.

Methane is an important GHG associated with ruminant livestock production estimated to account for 75% of Irish GHG emissions. Reducing the volume of methane produced by ruminant livestock will be critical to achieving our climate change targets. The main debate on reducing emissions is generally linked to bovines, but the sheep sector is also part of the discussion and is expected to also play a part in lowering emissions.

One of the greatest challenges on the sheep side of the house is that there is relatively little information available – particularly in the context of typical Irish production systems – of how much methane sheep produce and what production factors are at work.

Teagasc research

Teagasc has ramped up research in this area in recent years. Since 2019, particular focus has been given to the use of portable accumulation chambers (PAC) to measure methane. In simple terms, these are chambers that sheep stand in for a period and methane is measured during this time.

While the use of PAC has revolutionised findings on sheep, it has a significant drawback in that it won’t deliver absolute values that are recognised by legislators. This system is also labour intensive to operate and does not lend itself to continual measurements over large numbers across the year.

New technologies have been introduced in 2024 with a GreenFeed machine now being used in tandem with automated sheep feeding stations. Eoin Dunne, Sheep Sustainability Technologist positioned in Mellows Campus Athenry, explains that access to the new equipment will greatly enhance the level and accuracy of information collected. It will also provide inventories and validate PAC measurements.

Automated system

The new equipment is currently used to collect information on ewe lambs which are part of the INZAC trial. Eoin explains that in the past, collecting any measurements on intake was extremely demanding on labour with sheep housed in individual pens and all feed offered had to be weighed in and out by hand to record intake.

The new automated feeders measure intake every time an animal eats. The feed stations can accommodate four sheep per feed box or 16 per group with four feed boxes working together. Animals have free access all the time with the access door recognising each animal by their RFID tag.

As well as delivering intake information the feed boxes will give valuable information around feeding habits of sheep, breed differences etc. The feeding stations themselves do not measure methane and this is carried out by a GreenFeed machine.

GreenFeed system

In simple terms, the GreenFeed system is similar to a feed bin that has the capability to measure methane, hydrogen and CO2. A small amount of concentrates / grass pellets is dispensed to retain the animal’s head inside the feed bin. The animal’s electronic tag again provides the identification and samples of its breath are collected while at the machine. This information is fed into an algorithm to generate accurate readings on emissions.

The system can be used outdoors or indoors and there are plans to collect data right across the production year. A major benefit of the system is that it can collect data while animals are grazing numerous times a day. The frequency by which animals access the GreenFeed machine can be set at the desired number. If an animal visits the machine and insufficient time has lapsed since it last visited then it will not dispense any feed.

Genetic potential

Research is also ongoing by Teagasc and Sheep Ireland investigating the potential of genetic selection in breeding sheep with lower methane output. Noirin McHugh, Teagasc geneticist, says research undertaken to date shows positive heritability and repeatability figures which show there is potential to select for sheep with lower GHG emissions.

The next step is discussions on whether or not this should be included in the breeding index.

Research will continue to be collated as further measurements are collected via the GreenFeed system and it is very likely in the future that this could form part of breeding indexes.

A new international project, Sustain Sheep, which aims to create knowledge and infrastructure to incorporate genetic merit for low environmental impact traits into national breeding schemes, has received Department of Agriculture funding under the Green ERAHUB funding programme.

The project will be headed up by Fiona McGovern, Teagasc, with support from Sheep Ireland and will collaborate with overseas research. This will provide a platform for the comparison of methane and carbon dioxide emissions to enable selective breeding of lower-emitting animals.

This approach of balancing an economic value for methane within a multi-trait breeding programme is important, as focusing solely on methane could undermine profit traits. Teagasc says that understanding the impacts of reducing greenhouse gas emissions (GHG) on other animal characteristics, such as growth, feed intake and efficiency, and quantifying these effects is a crucial aspect of the project.