Grassland, or pasture, covers a large proportion of the global land area. Provision of food from grassland-based production systems plays an important role in global food security, through conversion of a low-cost human inedible food source (grassland) by ruminants into high-quality food for human consumption. Agricultural reforms and policy, increased demand for feed and food, and environmental considerations and the requirement to reduce foodfeed competition suggest that self-suffcient farming using locally produced or on-farm resources such as grazed grass will become more important in the future (e.g. Hofstetter et al., 2014). Dillon et al. (2005) and Hanrahan et al. (2018) showed that key drivers of proftability at farm level in temperate regions are associated with the proportion of purchased feed in the diet of the animal and with increased grass utilisation. It has been estimated that the demand for animal-derived protein may double by 2050 (Henchion et al., 2017). Maximising production effciencies while minimising environmental and ecosystem impacts will be crucial to meet this demand, while also contributing to the achievement of climate and biodiversity goals.