Now that we have tools to rank the animals according to the best estimate of their genetic potential, we are ready to start selecting the best animals for breeding. Immediately new questions are arising, because how many animals should we select? What are consequences if we select more or fewer animals? And for how long should a breeding animal be in service? Should we differentiate between parents that breed the next generation and eliminate parents that breed new parents? In this chapter tools will be presented to answer these questions. You will also learn that selection decisions often are steered by practical limitations.
If we look at the diagram again with the stages involved in the breeding program circle, then we have moved from the stage of determining selection criteria to the stage of actual selection and mating. In this chapter we will concentrate on the consequence of selection decisions by predicting response to selection. Mating will be subject of the next chapter.