Before implementing selection based on quantitative trait loci(QTL) for fertility, it is important to determine the existenceof correlated effects between the fertility QTL and QTL witheffects on production traits. When a QTL is detected for a traitthat is a composite of subtraits, it is of interest to validatewhich of the subtraits are affected by the QTL. Phenotypic andmarker data were collected from 34 grandsire families from theDanish Holstein population. First, the trait data for "fertilitytreatments" were separated into their underlying subtraits:uterine infections, antibiotics placed in the placenta, andabortions. In addition, retained placenta was selected for analysisbecause it is related to uterine infections. A genome scan wasperformed using 416 microsatellite markers for the fertilitytreatment subtraits and retained placenta, and an additionalgenome scan for milk production traits conditional on the QTLregions for the subtraits and retained placenta was conducted.Second, we selected 24 genomic regions harboring QTL for fertilitytraits from a previous study. A QTL scan for milk productiontraits conditional on the selected regions was conducted. Wefound that 16 selected genomic regions containing a QTL forfertility (including the fertility treatment subtraits and retainedplacenta) also harbored QTL for milk yield or milk compositiontraits. Furthermore, 12 QTL regions corresponding to 9 differentfertility traits (including the fertility treatment subtraits)did not harbor a QTL for milk production or milk compositiontraits; that is, the region was specific for the fertility trait.The genome scan for the fertility treatment subtraits did notcorrespond to the QTL found for fertility treatments. No QTLwere detected for the subtrait abortion, however genome scansfor retained placenta revealed 4 different QTL