Abstract. Ruminant livestock are raised under diverse cultural and environmental production systems around the globe. They can play a critical role in food security by supplying high quality, nutrient-dense food with little or no competition for arable land, while simultaneously improving soil health through vital returns of organic matter. However, in the context of climate change and limited land-resources, the role of ruminant-based systems is uncertain due to their reputed low efficiency of feed conversion (kg feed required per kg product) and production of methane as a by-product of enteric fermentation. A growing human population will demand more animal protein, which will put greater pressure on the earth’s planetary boundaries and contribute further to climate change. Livestock production therefore globally faces the dual challenges of mitigating emissions and adapting to a changing climate. This requires research-led animal and plant breeding and feeding strategies to optimise ruminant systems. This study has collated information from a global network of research farms reflecting a variety of ruminant production systems in diverse regions of the globe. Using this information, key changes in the genetic and nutritional approaches relevant to each system were drawn, that if implemented, would help shape more sustainable future ruminant livestock systems.