Sustainability & efficiency

Reducing carbon footprint while maintaining flock profitability: the finishing touch for the Irish sheep industry

---

Abstract

The objective of this paper was to create a methane module in Irish sheep breeding objectives to aid reducing the carbon footprint for the sheep industry while preserving genetic gain on key farm profit traits. The breeding objective for sheep in Ireland is comprised of Terminal and Replacement profit indexes. Currently, an across-breed single-step genomic evaluation runs in 4 independent modules: production, lambing, litter size, and health. The new methane module includes direct methane emission (g/day) measured from portable accumulation chambers (PAC) for 3,102 records from 2,052 lambs and 11,906 records from 5,019 ewes. Lambs weights measured at 40 days (n=329,177), weaning (n=385,861), and pre-slaughter (n=252,794) as well as ewe weight (n=58,364) were used as correlated traits to ewe and lamb methane. In the evaluation post-process, two methane goal traits were computed and integrated into the Terminal and Replacement index. Enteric methane from lamb methane PTA as well as non-enteric methane based on lamb survival and age at slaughter PTAs were included in the Terminal index. The Replacement index included enteric methane from lamb and ewe methane PTAs as well as non-enteric methane based on lamb survival, age at slaughter, litter size, ewe barren rate, ewe weight, and maternal weaning weight PTAs. The genetic trend for ewe methane emission averaged +0.016 g/day (+0.04 PTA standard deviation) per year across the main pedigree sheep breeds populations. Difference of 1.85 g/day in ewe methane PTAs was observed between the main pedigree sheep breeds. Using the sheep Teagasc Bio-Economic Model, all economic values applied to the goal traits in the Terminal and Replacement indexes were updated to include methane and carbon costs; mainly increase in costs of production, increase in number of lambs born per ewe and lamb sales. In terms of re-ranking and comparison to the current evaluation, the evaluation including methane, carbon costs, and updated economic values accentuated already present differences (i.e., the best ram get better and vice-versa) and therefore accelerated genetic gains. Index correlations between current and updated scenarios were greater than 0.90. In terms of response to selection, the new Terminal index accounting for methane and carbon costs maintained growth while constraining lamb methane emissions; the new Replacement index maintained genetic gain on maternal traits while reducing ewe methane emissions.

Keywords: 2026

How to Cite:

Anderson, J., Godfrey, S., Herron, J., McHugh, N., O' Connor, E. & Pabiou, T., (2026) “Reducing carbon footprint while maintaining flock profitability: the finishing touch for the Irish sheep industry”, World Congress on Genetics Applied to Livestock Production Digital Archive 2026(1): 2285368. doi: https://doi.org/10.31274/wcgalp.23660

Rights: 1