Three productionsystems for sheep (Low - L, Medium - M and High - H technology), with increasingtechnological levels, were studied under conditions in the Center-west of Brazil,to determine economic weights and selection indices of important traits. Receiptsand costs were simulated using an economic simulator to calculate the structureof the operational costs. Only characteristics that were responsible for morethan 10% of the profit were studied, which included: number of weaned lambs,food consumption (ewe and lamb), weight of carcass and weight of female lambssold for reproduction. Regardless of the index used (profitability or yield)or system (L, M or H), the economic weights are larger for the number of lambsweaned per ewe. With improvement in the technology used within the productionsystem (H to L) the importance of this trait becomes less important. Lamb growthincreased and weight of female for slaughter decreased in importance in highertechnology systems. Changes in herd structure had little influence on economicvalues, whereas (co)variances were important sources of change in selectionindices.
