Modelling the production, profit, and greenhouse gas emissions of Irish sheep flocks divergent in genetic merit

Sheep production industries face the challenge of increasing farm and profit while reducing environmental impacts. Genetic selection using multi-trait breeding indices can be used to improve flock productivity, profitability, greenhouse gas (GHG) emissions intensities (kg CO2-eq /kg product), however validation improved performance animals ranked higher on at a level is required. Phenotypic data from 387,580 records born between 2018 2020 known genetic merit in commercial flocks were inputted an established bio-economic model. Two contrasting compared, ewes High (top 20%) Irish replacement Index bred with rams terminal indices, Low (bottom indices. The two then simulated life cycle assessment estimate GHG profile for both systems. Flock weaning rates 1.70 1.53 lambs weaned per ewe presented flocks, respectively. sold 0.17 more ewe, equating 3.29 kg lamb carcass than ewes; also earlier age. greater resulted additional €18/ewe net flock. Although total flock, lower 21.7 23.3 intensity was due dilution effect being drafted slaughter ealier. results suggest sheep producers make substantial gains through according national their impact, farmers should consider when purchasing rams, particularly sires lambs.