Genetic and economic evaluation of genetic improvement schemes in pigs I. Methodology with an application to a three-way crossbreeding scheme

A method is presented for evaluating selection strategies fora three-way cr oss in pigs. Multitrait selection is considered. The criteria of evaluation are the annual genetic gains in the breeding objective and its component t raits, and the profit which is the net present value of return from investm ent in the scheme. Selection in the sire line (Pietrain) contributes higher returns than selec tion in the dam lines. Meat percentage is the dominant trait in the sire li ne and has the highest impact on the breeding objective. The sire line is c haracterised by a negligible economic weight for the reproduction trait and has higher weights than dam lines for growth and carcass traits. The highe r discounted economic values of these traits for Pietrain compared to those for darn lines deviate considerably from the equal weighting often applied in practical breeding programmes.