Breeding for sustainability: Development of an index to reduce greenhouse gas in dairy cattle

We partnered with Lactanet, Genome Canada, and international collaborators to formalise a greenhouse-gas (GHG) selection index that balances economic merit with the imperative to cut dairy emissions. The paper documents the data streams (mid-infrared methane proxies, GreenFeed phenotypes, feed efficiency, body maintenance requirements), the scaling of Canadian economic values to CO₂e, and the scenario testing used to weight traits under different policy levers. We show that including a direct methane trait alongside Herd Life, Feed Efficiency, and Body Maintenance Requirements avoids undesirable responses and delivers an expected 168 kg CO₂e reduction per cow per year per SD of index. The work also outlines how other breeding programmes can plug local methane EBVs into the framework to report transparent, auditable sustainability gains.