For those participating in the Beef Data Genomics Programme (BDGP), there is a requirement that a percentage of heifers/eligible suckler cows be genotyped females that are four or five stars on the replacement index (on a within-breed or on a crossbreed basis) at the time of purchase (for heifers brought into the herd) or at the time of genotyping (for those replacements bred within the herd).