zlacker

Detail in there: during winter, UK livestock are sometimes fed silage, which is grass that has been harvested during the summer and partially fermented. UK is majority local production, but there's significant imports from Ireland.

People talk a lot about water and land use, but if you have the conditions of land that is (a) naturally watered and (b) not flat enough for arable farming, using it for livestock is much more environmentally friendly than, say, feeding them imported soy - leaving only the methane problem.