UC Davis

As global temperatures continue to rise, the urgency for effective greenhouse gas (GHG) mitigation strategies becomes increasingly critical. The dairy industry, in particular, faces scrutiny due to its direct GHG emissions from enteric fermentation and manure management, as well as indirect emissions from feeding, housing, and farm operations. This work focuses on GHG emissions associated with dairy production, aiming to contribute to the goal of limiting warming to well below 1.5°C.The first project examined the impact of 50 years of intensification on California's dairy industry. The study demonstrated how advancements in genetic selection, crop cultivation efficiencies, and byproduct inclusion led to significant reductions in GHG emissions, water use, and land use. While substantial reductions were achieved in feed production, farm management and enteric methane emissions, the study identified a lack of equivalent improvements in manure management, particularly in the use of anaerobic lagoons, highlighting the need for updated practices and more accurate data collection. The second project focused on dairy production in South Dakota, where the carbon footprint of milk production was found to be higher than in California. Through consequential analysis, two strategies were explored for emission reductions: local sourcing of feed and the use of anaerobic digesters to mitigate emissions from manure management. The project emphasized the importance of region-specific strategies and the potential for biogas production to offset energy demands and provide additional revenue streams for producers. The third project examined large-scale dairies in Mexico, which, despite representing only 3% of the country’s operations, produced half of the nation’s milk. This study highlighted disparities in efficiency between Mexican dairies and those in the U.S. and California, particularly in feed production, farm management, and in some cases manure management. The study explored various mitigation strategies at each dairy, including switching from anaerobic lagoons to composting, applying composted manure as organic fertilizer, an enteric methane-inhibiting feed additive, upgrading to energy efficient equipment, and improving forage production efficiency. While the field is moving in a positive direction, more widespread adoption of sustainable practices is essential to meet global climate goals and limit warming to well below 1.5ºC. This dissertation contributes to the understanding of how production efficiencies, strategic management practices, and innovative technologies can be harnessed to create a more sustainable dairy industry.