The increasing use of genomic selection has resulted in a shorter generation interval, reduced effective population size, increased selection intensity and consequently an increased annual rate of inbreeding. Inbreeding accumulation is a growing concern for the dairy cattle industry, mainly due to strong negative correlations that exist between inbreeding and fitness traits. On an animal level, increased homozygosity is associated with increased risks of disease susceptibility, defects, or death based on the presence of deleterious alleles, and loss of genetic diversity on a population level. Identification of regions containing deleterious alleles are, therefore, pertinent for genetic improvement purposes. Conventionally, estimation of inbreeding coefficient has been done using pedigree information, with SNP data more recently included when available. The availability of genomic information and the increasing number of Canadian dairy animals with genotypic records has led to the use of runs of homozygosity (ROH) in predicting or estimating inbreeding. ROH are unbroken homozygous SNP regions present on homologous chromosomes of a specific animal. In a previous internal study, PLINK, SNP1101 and BCFtools were used to identify and characterize ROH in Holstein animals using >150,000 50K genotypes and >3,500 HD genotypes provided by the Canadian Dairy Network (CDN), and 402 whole-genome sequence genotypes made available by the 1,000 Bull Genomes project. In the current analysis, these ROH regions will be annotated using Kyoto Encyclopedia of Genes and Genomes (KEGG), an online bioinformatics resource and Variant Effect Predictor (VEP), a freely distributed software. Positions of annotated ROH will be determined and further investigated to evaluate their effect on genes, transcripts, and proteins. Additionally, analysis to determine whether amino acid substitution changes the protein structure will be performed. The Canadian dairy industry will benefit from these results as the inclusion of annotated ROH regions in selection strategies may help manage deleterious alleles, control inbreeding and ultimately improve fitness performance of the Canadian dairy Holstein population.