This study assessed the effects of different prepartum supplementation plans on Nellore cows’ performance, metabolic responses, and early offspring development. Thirty-nine pregnant Nellore cows (224 ± 2.67 days of pregnancy, 5.3 ± 0.29 years of age, body weight 520 ± 15.2 kg, initial body condition score 6.0 ± 0.07) were assigned to one of four treatments: a control group receiving only mineral mixture ad libitum, and three groups receiving daily protein-energy supplements of 2, 4, or 6 g/kg BW for 60 days prepartum. Weights and body condition scores were evaluated at the start of the experiment, 7 days before calving, and at 45 and 90 days postpartum. Cows supplemented with 4 and 6 g/kg BW showed improved body weight and body condition scores prepartum and postpartum and had a shorter service period (p < 0.05). The highest blood urea nitrogen concentrations were observed in cows receiving 6 g/kg BW (p = 0.0124). There was a reduction in blood urea nitrogen at calving for the 6 g/kg BW group, while the control group showed an increase (p < 0.001). Non-esterified fatty acids concentrations were lower 21 days before calving for the 4 and 6 g/kg BW groups compared to the control (p < 0.05) and decreased postpartum for all treatments (p < 0.001). No significant differences were observed in calf birth weight or performance. Supplementing with 4 g/kg BW of protein-energy is recommended to enhance metabolic health and overall performance.