The objective of this study was to evaluate the use of banana crop wastes in diets of ¾ Holstein × ¼ Zebu heifers on the intake and digestibility of nutrients, microbial protein synthesis, feeding behavior, and animal performance. Eight ¾ Holstein × ¼ Zebu heifers were utilized with an average age of 18 ± 1.0 months and an average body weight (BW) of 298 ± 3.06 kg. The experiment was distributed in two simultaneous 4 × 4 Latin squares. The treatments were as follows: Diet 1 (SS)—sorghum silage as exclusive dietary roughage; diet 2 (SSL)—sorghum silage (50%) associated with 50% leaf hay of banana trees (on a DM basis); diet 3 (SSBP)—sorghum silage (50%) associated with 50% banana peel hay; and diet 4 (SSPS)—sorghum silage (50%) associated with 50% pseudostem hay of banana trees. The roughage:concentrate ratio was 75:25. The greatest dry matter intake (DMI; p < 0.01) was found in heifers that received the SS and SSBP diet, mean of 10.19 kg/day. The SS diet showed greatest dry matter digestibility (DMD; p < 0.01) and crude protein digestibility (CPD; p < 0.01). The concentration of total purines (p < 0.01) and absorbed purines (p < 0.01), microbial protein synthesis (p < 0.01), and microbial efficiency (p < 0.01) was higher in the SSBP diet in comparison with SS and SSL diets. The longest eating time was observed in animals that received the SSL diet, being 17.79% higher (p = 0.01) than the SSBP diet. The final BW (p = 0.39) and BW gain (p = 0.39) were similar, with averages of 319.84 kg and 1.08 kg/day, respectively. Biometric measurements were not altered as a function of bedtime (p > 0.05). Banana wastes can be used to feed ¾ Holstein × ¼ Zebu heifers in partial replacement for sorghum silage as they do not alter the animals’ weight gain and body development.