Profitability of a pork production system relies on reducing the cost per unit of output that is achieved. There are opportunities to increase the profitability of the pork production system by genetic improvement of performance traits. Selection of superior individuals as parents within breeds and choice of breeds or composite lines to be used in crossbreeding systems are the general tools that breeders have available to bring about this genetic improvement. The use of genetically selected sire and dam lines enhances the performance of terminal crossbreeding systems. In this publication,
the potential for greater genetic improvement through the use of specialized sire and dam lines is discussed.