Two experiments were conducted to determine the influence of plane of nutrition during (1) the pre- and immediate postweaning periods and (2) the grower phase on the performance and leukocyte responses of Holstein calves. In experiment 1, 39 (2 ± 1 d old) colostrum-fed heifer calves were randomly assigned to 2 planes of nutrition, a low (LPN; n = 19) and a high plane of nutrition (HPN; n = 20). Calves in the LPN treatment were offered 418 g/d of dry matter (DM) of a 20% crude protein (CP)/20% fat milk replacer, whereas calves in the HPN treatment were offered 747 and 1,010 g/d of DM of a 28% CP/20% fat milk replacer during wk 1 and wk 2 to 6, respectively. Calves were offered ad libitum access to a calf starter until the end of the study.