A whole genome scan to map quantitative trait loci (QTL) for persistency of milkyield (PMY), persistency of fat yield (PFY), persistency of protein yield (PPY)and persistency of milk energy yield (PEY) was performed in a granddaughterdesign in the German Holstein dairy cattle population. The analysis included 16paternal half-sib families with a total of 872 bulls. The analysis was carriedout for the first lactation and for the first three lactations combined usingunivariate weighted multimarker regression. Controlling the false discovery rateacross traits and data sets at a level of 0.15 and treating the four persistencytraits as different traits revealed 27 significant QTL. A total of 12chromosomes showed significant QTL effects on a chromosomewise basis. The DGAT1effect was highly significant for PPY and protein yield. A haplotype analysisusing results of previous studies of the same design revealed a co-segregationof various persistency QTL and QTL affecting health traits like dystocia andstillbirth and functional traits like non-return rate 90 and somatic cell score.