Description of Research: Genetically modifying animals is a tool that can be used to increase livestock production. The gene editing technology CRISPR has expanded the possibilities of gene editing. The Cas9 nuclease creates a double strand break which can be repaired by non-homologous end joining (NHEJ) or homology directed repair (HDR). The goal of this experiment was to create a single nucleotide change using the CRISPR/Cas9 system in combination with a single strand oligo nucleotide (ssODN). The single nucleotide that was targeted occurred naturally in Holstein cattle, and is associated with increase milk production.