Economic analysis of Merino ewe performance from diverse industry sires using GrassGroTM

Differences in profitability between genetically different sire groups at the Macquarie site of the Merino Lifetime Productivity Project (MLP) were compared using GrassGro™ to simulate animal performance based on the interactions between animal production and pasture growth determined by historical climate data. Mean gross margin (GM) differences of $13/Dry Sheep Equivalent (DSE) and $42/head (hd) were found between sire groups for wool and meat median prices. In median to high markets wool income had a higher influence on GM/DSE than meat income, with fibre diameter being the trait of most influence. In low markets meat income had a greater influence on GM/DSE with weaning rate the most influential single trait. Utilising a combination of traits, through either of three different selection indexes, showed the strongest correlations with GM/DSE.