Peer-reviewed article Food intake and feeding behaviour of Holstein-Friesian (HF) and Jersey × Holstein- Friesian (J × HF) dairy cows (14 primiparous cows of each genotype) were measured during a 54-day confinement period [cows offered a complete diet comprising conserved forage and concentrates; 66:34 dry matter (DM) basis], while herbage intakes and grazing behaviour were measured on three occasions during a 96-day grazing period. Throughout the experiment HF cows had a higher milk yield than J × HF cows (P < 0.05), while fat + protein yield was unaffected by genotype. During the confinement period HF cows had a higher food intake than the J × HF cows (P < 0.01), although DM intake/kg metabolic live weight (live weight0.75) was unaffected by genotype. With the exception of the number of ruminating bouts/day (P < 0.05), and idling time/day (P < 0.05), both of which were highest with the J × HF cows, genotype had no significant effect on any of the feeding behaviours examined during the confinement period. Herbage intake did not differ between genotypes during the grazing period, although when expressed on a kg live weight0.75 basis, intakes were highest with the J × HF cows (P < 0.05). While the smaller J × HF cows had fewer grazing bouts per day (P < 0.01), the mean duration of each grazing bout was longer (P < 0.001), resulting in a longer total grazing time (P < 0.05) and a greater number of grazing bites each day (P < 0.01). The smaller crossbred cows had to ‘work harder’ during the grazing period to achieve the same intakes as the larger HF cows. Department of Agriculture and Rural Development for Northern Ireland (DARD); Agri-Search