Genetic and economic evaluation of genetic improvement schemes in pigs. – II. Comparison of selection strategies in a three-way crossbreeding scheme
Abstract. Alternative selection strategies for a three-way cross in pigs (Pietrain as the sire line and Large White boars mated to German Landrace sows to produce the F1-female) are investigated to maximise both genetic gain and profit. The number of nucleus sows in the main female line (German Landrace) can vary within a wide range without noticeable effect on the genetic and economic response. Productive lifetimes of approximately one year are recommended for nucleus boars and sows after the progeny test. Boars mated to produce crossbreds should be used longer, especially in the terminal sire line. F1-sows can have a productive lifetime of more than two years and can be used close to their biological maximum.
Four testing schemes are compared and the contribution of the three breeds to the return is evaluated. Testing crossbred animals at a central test Station cannot be recommended. This capacity should be used to test purebred animals. Both monetary genetic gain and profit are higher in a scheme with a self-performance testing of boars at Station, in comparison to a scheme with only progeny testing at Station, by 36 and 68%, respectively. Due to a reduced generation interval, using boars to produce breeding boars straight after their self-performance test leads to a further increase of monetary genetic gain by 5% and profit by 13%. In all schemes, selection in Pietrain leads to the highest return due to the highest gene proportion in and its shorter distance to the terminal product and the therefore faster transfer of genetic gain.