A genome-wide association study of Nordic Holstein cattle SNP chip genotypes and imputed next generation sequencing (NGS) variants identified carcinoembryonic antigen-related cell adhesion molecule 18 (CEACAm 18) on BTa 18 as the gene most highly significantly associated with direct calving traits. Phenotypes used were estimated breeding values (EBV) for six direct calving traits and one compound index trait. A SNP by SNP mixed model approach was first applied using HD genotypes. Haplotypes in the significant region were fitted in a mixed model. Finally, NGS variants in the significant region were utilized to precisely locate causative mutations. Results identified 21 QTL regions associated with one or more calving traits on 16 autosomes. These findings contribute to an improved understanding of the genetic architecture of the calving traits. They may help in improving calving performance in dairy breeding programs