A paper produced in the frame of the H2020 project 677353 'Innovative Management of Animal GEnetic resources' This study investigates the effects of recent and ancient inbreeding on yield, fertility and udder health traits in Dutch Holstein–Friesian cows. Inbreeding depression was observed for yield, fertility and udder health traits. For yield traits and based on pedigree, inbreeding on recent generations was more harmful than inbreeding on distant generations and there was evidence of purging. In future work, inbreeding depression and purging should be assessed in more detail at the genomic level, using higher density information and genomic time series, thanks to gene bank collections. ; The study was co-funded by the Dutch Ministry of Agriculture, Nature and Food Quality (KB-34-013-002). The authors gratefully acknowledge the Dutch-Flemish cattle improvement cooperative (CRV) for providing pedigree and genotype data