Different levels of hay and wet sugar-beet pulp were evaluated with lactating cows. ln Trial 1, 20 Holstein cows were used, in a complete randomized block design, during a 98 day period, to compare four treatments: I) 0.5; II) 1.3; III) 1.8, and IV) 2.3 kg of hay/100 kg of uve weight. AIl treatments also received: wet sugar-beet pulp adlibitum, 1.5 kg of rapeseed meal and 0.2 kg of a mineral mix-ture/cow/day. MiIk production (4% FCM) was 9.9,11.2,11.2, and 12.2 kg/cow/day (P > 0.05), and total dry matter (DM) intake was 11.2a, 13.2b, 13.5b, and 14.2b kg/cow/day (P < 0,05), for treatments I, II, III and IV, respectively. In Trial 2,25 Holstein cows were used, duning a 126 day period, to compare five treatments; I) 0.25, II) 0.70, III) 1.10, IV) 1.75, and V) 2.40 kg of hay/100 kq live weight. The other part of the ration, was similar to Trial 1. Production of FCM was 10.9, 13.0, 12.7, 12.5, and 12.4 kg/cow/day (P > 0,05), and total DM intake was 13.7, 13.7, 12.8, 14.0 and 14.2 kg/cow/day (P > 0.05), for treatments I, II, III, IV, and V, respectively. In both trials, addition of different levels of hay aboye 0.25 kg/100 kg of live weight had no effect on FCM production. Supply of different levels of hay will depend on the comparative costs of hay vs. pulp.