A range of factors influence the preference grazing livestock have for forage plants. We determined the preference of dairy heifers for temperate perennial pasture grasses, and relationships among DM consumption, forage availability, and resistance to particle size reduction in dry forage. Eight Holstein heifers (320 kg mean body weight) were given access to each of four replicates of 11 grasses (3.0- by 6.0-m plots) for 8 hr when grasses reached 25 to 30 cm height in early May, mid-July, and late September. Plots were sampled for DM availability before grazing and DM consumed after grazing (10-cm stubble). Dry, intact-leaf samples (5.0 g) of each grass were tumbled with stainless steel balls for 30 s and sieved through 6- and 1-mm sieves for 60 s. Forage availability ranged from 2600 to 4460 kg DM ha^-1 in the spring, 1230 to 2680 kg DM ha^-1 in the summer, and 600 to 1300 kg DM ha^-1 in the fall. Heifers exhibited greatest preference for festulolium [Festulolium loliaceum (Hudson) P.V. Fournier], ryegrass (Lolium perenne L.), and timothy (Phleum pratense L.) in the spring, meadow fescue (Festuca pratensis Huds.) and timothy in the summer, and quackgrass [Elymus repens (L.) Gould] and timothy in the fall. The correlation (P ≤ 0.05) between forage consumed and availability was 0.51, 0.50, and 0.35 in the spring, summer, and fall, respectively. The correlation (P ≤ 0.05) between forage consumed and the leaf fraction that did not pass a 1 mm screen was -0.26, -0.36, and -0.22 in the spring, summer, and fall, respectively. In each season, factors not measured influenced preference; forage availability was not positively associated with preference in some grasses, such as tall fescue and timothy.