TABLE 2

Genetic parameters for a population selected with a sib index

 Xm, Xf d Number of male and female parents and mating ratio d = Xf/Xm nm, nf, no Number of male and female offspring in a full-sib family, no = nm + nf P, , Phenotype of candidate and its full- and half-sib family means I, b1 b2, b3 Index and weights for selection pm, pf Selection proportions for males and females: pm = (nmd)−1, pf = nf−1 Vm, Vf, im, if, km, kf Truncation points, intensities of selection, and variance reduction coefficients Variance of the index, total genetic variance, and accuracy of selection Genetic variance among selected sires and dams and residual variance Ai(hs), Aj(fs) Mean breeding value of the half-sib family of sire i and the mean breeding value of the full-sib family of dam j expressed as a deviation from the half-sib family V(Ai(hs)) Variance of Am and similarly defined for ρFS, ρHS Correlation of indices among full-sibs and half-sibs, respectively:
• In the initial unselected base population, the phenotypic variance was assumed to be 1 and the initial heritability