Responses to Individual, Family or Index Selection for Short Term Rate of Egg Production in Chickens

Abstract

THE theory of selection and the relative efficiency of various methods of selection have been discussed in detail by several workers: Lush (1948), Lerner (1958), Falconer (1960), Osborne (1957a, b) and others. Probably the most detailed development of theory with respect to reltive gains expected from various methods of selection, most likely to be employed by poultry breeders, is that presented by Osborne (1957 a, b). The four methods of selection discussed by Osborne are, a) full-sib family selection, b) half-sib family selection, c) index selection in which weights are assigned to full-sib and half-sib family averages, and d) index selection in which weights are assigned to full-sib and half-sib family averages and to individual records. Osborne discusses the theoretical efficiency of these systems relative to each other and relative to individual (mass) selection. His development indicates that expected gains, when a trait is low in heritability and the same . . .