This study evaluated the interactive effects of forageprovision on performance, nutritional behavior,apparent digestibility, rumen fermentation, and bloodmetabolites of dairy calves when corn grains with differentfermentability were used. Sixty 3-d-old Holsteincalves were randomly assigned to 1 of 4 treatments ina 2 × 2 factorial arrangement. Dietary treatments were(1) steam-flaked (SF) corn without alfalfa hay (AH)supplementation (SF-NO), (2) SF corn with AH supplementation(SF-AH), (3) cracked (CR) corn withoutAH supplementation (CR-NO), and (4) CR corn withAH supplementation (CR-AH). All calves received thesame amount of pasteurized whole milk and weaned ond 56 of the experiment; the study was terminated on d70. Steam-flaked corn contained higher amounts of gelatinizedstarch in comparison with cracked corn (44.1vs. 12.5% of total starch, respectively). Starter intakewas not affected by corn processing methods or AHprovision during the pre- or postweaning periods. However,we noted an interaction between corn processingmethods and forage supplementation for starter intakeduring d 31 to 50 of the experiment, where calves fed onSF-AH starter had greater starter intake than those fedSF-NO starter, but the starter intake was not differentbetween CR-NO and CR-AH fed calves. Furthermore,AH increased average daily gain (ADG) of calves fedan SF-based diet but not in calves fed a CR-based dietduring the preweaning and overall periods. Interactionbetween forage provision and time was significant forADG and feed efficiency, as calves supplemented withforage had higher ADG (0.982 vs. 0.592, respectively)and feed efficiency compared with forage unsupplementedcalves at the weaning week. Forage supplementationresulted in more stable ruminal condition comparedwith nonforage-fed calves, as evidenced by higherruminal pH (5.71 vs. 5.29, respectively) at postweaningand lower non-nutritive oral behavior around weaningtime (55 vs. 70.5 min, respectively). The concentrationof blood β-hydr
