Dairy heifers developed in certified organic programs, especially those on primarily pasture-based management schemes, have a lower rate of gain than heifers raised in conventional production systems. Slower growing heifers have a delayed onset of puberty, which can result in economic inefficiency for producers. Furthermore, it is suggested that organically raised heifers are at an increased risk for internal parasitism because some commercial anthelmintics are limited by rule. This study investigates the effects that different forages in a rotational grazing system have on growth and performance of organically raised dairy heifers. We hypothesized that different pastures will affect growth and reproductive efficiency of developing heifers. To test this hypothesis, a trial was conducted over a period of 2 yr (year 1: n = 48, year 2: n = 81). A conventional dry lot control and 8 different pasture treatments were utilized. Treatments included tall fescue (TF), meadow brome grass (MB), orchard grass (OG), perennial rye (PR) and each of these grasses interseeded with the legume birdsfoot trefoil (BFT). Yearling Jersey heifers (n = 129) were randomly assigned to 1 of 8 different pasture treatments (n = 15) or a dry lot control (n = 9). Every 35 d, during a 105-d period, heifers were weighed, measured for hip height, and blood and fecal samples collected to determine serum insulin-like growth factor-1 (IGF-1) and blood urea nitrogen (BUN) concentrations, along with fecal egg per gram counts. At the end of the 105-d period, heifers were bred and checked 30 d post-breeding to determine conception rate. Repeated-measures analyses were performed using PROC MIXED in SAS (version 9.4) to determine how treatment affected each measurement over the total 105-d period. Pasture altered weight gain (P = 0.01) and serum BUN concentrations (P < 0.01) over the 105-d period. Specifically, animals that consumed BFT had increased (P < 0.01) weight gain and serum BUN concentrations compared with animals that consumed a grass monoculture pasture. However, no differences (P > 0.05) between treatments relative to hip height, serum IGF-1 concentration, fecal egg counts, or conception rate were observed over the 105-d period. These data provides insight into how different forages in organic pastures may affect growth and productivity of dairy heifers.