<p>Simulation was used to illustrate the effects of genomic selection on estimates of genetic parameters, comparing values when genomic relationships were ignored with those obtained accounting for the joint relationship matrix of genotyped and non-genotyped individuals. Analyses were carried out with increasing truncation of earlier records, pedigrees and genotype information. Results showed that estimates from pedigree only analyses could be markedly biased downwards as more historical data is ignored, especially with strong genomic selection, causing predicted breeding values for selection candidates in the last generation to be under-dispersed.</p>