ABSTRACT:
In developed countries, selection indices is usually used lid the genetic improvement of sheep. One of the most critical assumptions used in constructing multiple trait selection indices is that parameters such as genetic and phenotypic variances and covariances are known without error. hi practise, however, only estimates of these parameters arc used, and these are subject to sampling error. The objective of the present paper is to calculate genetic selection indices in sheep breeding using the "bending" technique develeved by Gunawan (1986). In the final model, 11 production traits are used in the breeding objective and W characters in th. index. The results show that the accuracy of selection ranged from about 0.62 to
0.80, The efficiencies of selection indices ineludini4 all traits relative to single trait selection are also calculated. The results show that selection indices are always more efficient than single trait selection. The efficiency ranged from about 102% to 176%. The highest relative efficiency is for traits with low heritability (h2=0,144,20), with efficiencies of 176% and 139% respectively. For traits with moderate heritability 012=421-0.0) the efficiencies ranged from 115% to 132%, and for traits with high heritability (h2>0,40) efficiencies are between 102% and 101%, it is concluded that a selection index is very efficient if the trait has a low heritability but also relatively high correlations with characters of high heritability in the index.
Key Words : Selection Indices, Single Trait Selection, Genetic & Phenotypic Parameters,
Bending Technique.. Breeding Objective, Heritabilit
