Many dairy farms also grow their own feed, typically including corn, alfalfa, and hay.
British Dictionary definitions for alfalfa
a leguminous plant, Medicago sativa, of Europe and Asia, having compound leaves with three leaflets and clusters of small purplish flowers. It is widely cultivated for forage and as a nitrogen fixer and used as a commercial source of chlorophyll Also called lucerne
C19: from Spanish, from Arabic al-fasfasah, from al the + fasfasah the best sort of fodder