New carbon index enhances sheep breeding sustainability

Teagasc research has developed a carbon sub-index to integrate environmental impact within Ireland’s sheep breeding objectives. This innovation aims to reduce greenhouse gas emissions while maintaining productivity and profitability in the national sheep industry.

Reducing greenhouse gas emissions in agriculture remains a critical challenge for Ireland's climate goals. To address this, researchers at Teagasc, in partnership with Munster Technological University and Sheep Ireland, have pioneered a carbon sub-index to optimise sheep breeding for both production and environmental performance.

Integrating environmental traits into breeding

Traditionally, sheep breeding in Ireland focused predominantly on growth, meat quality, and maternal traits without considering environmental impacts. Now, the Irish national sheep breeding programme, underpinned by the Terminal and Replacement Indexes, has incorporated a carbon sub-index designed to estimate lifetime greenhouse gas emissions from individual animals, including methane, nitrous oxide, and carbon dioxide.

Lucy Chipondoro, a Teagasc Walsh Scholar leading this research, explains that two approaches informed the carbon sub-index: a lifecycle assessment model measuring total emissions from sheep production, and a combined model incorporating methane estimated breeding values for individual animals. The findings revealed that selecting for economically important traits often also reduced emissions, demonstrating compatibility between productivity and environmental goals.

Balancing productivity and environmental impact

Incorporating the carbon sub-index into existing breeding objectives altered the emphasis on trait groups within the indexes but did not compromise their core aims. Maternal traits remained dominant in the Replacement Index, while production traits featured more in the Terminal Index. This multi-trait selection approach allows farmers to consider profitability alongside sustainability effectively.

Research also indicated that increasing carbon prices raised the importance of carbon traits in breeding decisions, though with diminishing returns at higher prices. This suggests carbon pricing can incentivise environmental improvements without destabilising breeding objectives.

Since December 2025, the carbon sub-index has been officially part of the national sheep breeding programme, marking a significant advance towards reducing emissions in Irish sheep farming. Although greenhouse gas mitigation currently offers limited direct financial returns to farmers, emerging carbon farming initiatives could soon reward farmers for environmental stewardship, encouraging further adoption of sustainable breeding practices.

This research was supported by the Department of Agriculture, Food and the Marine’s IE-NZ Joint Call and the Teagasc Walsh Scholars Programme. For further information, contact Jonathon Herron at [email protected].

Understanding and selecting animals based on lifetime emissions represents a vital step in aligning sheep production with Ireland’s climate ambitions, ensuring a sustainable and profitable future for the sector.