Farm-level Modelling of Bioeconomic, Greenhouse Gas Emissions and Feed-Food Performance of Pasture-Based Dairy-Beef Systems

CONTEXT.Global demand for grass-based beef systems is increasing with a growing proportion of beef output in many countries originating from the dairy herd. Concurrently, concerns around the environmental impact of food, particularly that derived from ruminants, and food security is growing in prominence. Therefore, a compre-hensive analysis of the sustainability of dairy-beef systems is required.OBJECTIVES: The objectives of this study were to (1) augment an existing farm-level bioeconomic model to permit greenhouse (GHG) emissions and feed-food analysis of dairy-beef systems and (2) use this model to asses the performance of grass-based dairy-beef steer production systems.METHODS: The developed farm-level model was used to evaluate production systems finishing males as steers on three contrasting soil types and differing with respect to sire breed (early-maturing, late-maturing and dairy), age at slaughter (20, 24 and 28 months of age) and finishing diet (grazed grass or grass silage, each supplemented with concentrates).