The objective was to evaluate the metabolic and performance differences in primiparous Nellore cows, which became pregnant at 14 or 24 months. Thirty-eight primiparous Nellore cows, which were bred for first pregnancy at 14 or 24-mo of age, with 202 ± 5 days of gestation were divided into two treatments according to breeding age: 14 or 24 months in the breeding season. Cows were evaluated for weight, body condition score (BCS), carcass characteristics, milk yield and blood parameters: glucose, total proteins, albumin, urea, beta-hydroxybutyrate (β-OHB), non-esterified fatty acids (NEFA), progesterone, and for insulin-like growth factor-1 (IGF-1). There was an in-teraction (p < 0.01) between age at first pregnancy and time for body weight, where 24-mo cows were heavier, but both categories loss weight at parturition which concomitant decrease in the BCS (p < 0,01). However, BW of 24-mo remained stable (p > 0.05) after parturition. Milk yield was higher in 24-mo cows (p < 0.01). Interaction between sampling time and breading age was observed for Longissimus muscle area (p < 0.01) and tended for Longissimus muscle depth, where 24-mo cows had greater values in prepartum. Calves born from the cows bred at 24-mo, where was higher (p < 0.01) from 160 days of age until weaning at 240 days. Glucose, urea, total proteins, albumin and NEFA were affected (p < 0.01) by the parturition data-point. There was an interaction (p < 0.01) between breading age and sampling period for β-OHB. Progesterone concentration was greater in 24-mo cows (p < 0.01). It was concluded that primiparous cows that became pregnant at 14 or 24 months of age have different nutritional and metabolic responses.