Mitigation of methane (CH₄) emissions in dairy cattle production has become of particular concern in recent years, as it has been identified as being one of the most prevalent non-CO₂ greenhouse gasses contributing to climate change. To date, there have been studies describing the reduction of enteric CH₄ emissions through nutritional and microbial manipulation, though there is potential for greater and more permanent progress using genetic selection. It has been shown that there is sufficient genetic variation in enteric CH₄ to be possible to reduce its emission through selection programs. Determining an optimal breeding strategy for mitigation of CH₄ emissions would help reduce the environmental impact of the Canadian dairy industry. Enteric CH₄ production itself is challenging to measure directly, so selection on correlated traits to indirectly reduce CH₄ may be more cost effective and less labor intensive. Heritabilities along with genetic and phenotypic correlations between CH₄ emission and other traits of interest will be compiled or estimated. ZPLAN+ will be used to simulate and analyze breeding strategies that include CH₄ emission as a novel trait. ZPLAN+ is a software that allows the modeling and calculation of complex animal breeding scenarios using genomic information. The software will be used to model genetic gain, monetary returns, and costs associated with including this trait in the selection index for the Canadian Holstein population. Additionally, long-term effects of the proposed selection index and the correlations between CH₄ emissions and other traits of interest included in the current breeding strategy will be analyzed. Outputs from this project will provide insight for the Canadian dairy industry as how to best include new information into the existing selection index to reduce CH₄ emissions.