Developing a Breeding Objective for Dual-Purpose Merino Precoz Breed in Central Chile: Derivation of Economic Weights

Defining economically important traits is crucial in the design of a genetic program. These are referred to as the breeding objective, and determining their economic values ( ) is essential. Currently, no breeding objective has been established for Merino Precoz sheep in central Chile. This study proposes a breeding objective and calculates for five traits: greasy fleece weight (GFW), fiber diameter (FD) with three pricing scenarios: 3.5%, 7% and 14% of GFW price, number of lambs weaned (NLW), weaning weight (WW), and adult weight (AW). Economic values were: USD5.42 for GFW; USD-0.59, USD-1.18, USD-2.35 for FD scenarios (3.5, 7, 14%, respectively); USD151.1 for NLW; USD4.93 for WW, and USD-0.09 for AW. The greatest emphasis was placed on NLW and WW, which collectively represent over 80% of the breeding emphasis. A negative value for AW indicates that smaller ewes are preferable in production systems operating in drylands like central Chile. Furthermore, the inclusion of NLW in the breeding objective must be supported by reliable data-recording protocols and effective management practices to ensure accurate selection.