Project update - May 2025

Measurement of methane

13,341 measurements on 8,859 grazing ewes and lambs made to end of April 2025.  These represent 7 breeds and 30 flocks, all fully performance recorded.

Typically there is a 40-50% difference in the methane produced by the highest and lowest 20% of lambs in a flock.

Preliminary estimates show a heritability of 8% for weight adjusted methane output, but higher (>20%) for traits believed to be related to methane yield (CH4/kg DMI).

Resistance to roundworms

We want to understand how breeding a more efficient and healthy ewe can contribute to a lower carbon footprint.

Early analysis is showing that our two indicators of resistance to roundworms are highly heritable in our populations.

Feed efficiency and rumen biology

500 lambs have been measured for feed efficiency, rumen size and we have sampled the rumen microbiome.

There is lots of variation in rumen volume (typically 4 to 9 litres), and we are building data sets that will tell us more about the relationship of this trait with methane. Our early analysis of the rumen microbiome suggests this has an important influence on methane.

Farm Carbon Footprints

Carbon audits have been completed on 62 farms to help us understand how sheep bred for a lower carbon footprint will contribute to business objectives. The average footprint was 27 kg CO2e/kg dwt with variation between different farms and systems.

Developing a Selection Index

We are developing a selection index that can be used to rank breeding animals on their potential for reducing the flock carbon footprint. It will include measures of ewe efficiency and health in addition to traits directly related to methane emissions. Following the project this will be available for Signet and Innovis recorded maternal breeds.