The relationships among forage allowance (FA), forage mass (FM), and BCS during early (E) and middle gestation (M), calving (C) and lactation (L), and calf weight at weaning and calving conception interval (CCI) were studied employing records from an experiment that evaluated the effect 2 levels of FA on productivity of primiparous beef cows grazing Campos grassland. The study took place in Facultad de Agronomía, Uruguay (31°S 57°W). Eighty primiparous cows were assigned to a completely randomized experiment of 2 FA in spatial replication on 2 blocks during 2 years. The experiment started in autumn −150 d postpartum (dpp; early gestation [e]) and finished 190 dpp. Annual FA averaged 2.5 and 4 kg DM/kg liveweight (LW) for low (L) and high (H) FA, respectively. Cow LW and FM were measured monthly to adjust FA using the “put and take” method. The BCS was recorded (1–8 points scale). Calf birth weight (CBW) and weaning weight were recorded and calf weight adjusted at 205 d (CW) of age was estimated. Date of subsequent calving was recorded and CCI was calculated subtracting 285 d of gestation. Models were obtained by multiple regressions selected by Stepwise procedure (JMP 6.0). The BCSe, FAm, FMl, BCSe×FMl and CBW explain CW (CW = - 8.6 + (13×BCSe) + (4.9×FAm) + (0.036×FMl) + (1.8×CBW) – [0.024× (BCSe - 5.6) × (FMl −1400)] (r² = 0.54; P < 0.01; Mean = 187; RMSE = 15). An increase in one unit of BCSe, FAe, and FMl increase CW in 13, 4.9 and 0.036 kg respectively. The interaction BCSe*FMl showed an increase in CW when BCSe increases, in FMl levels below 2000 kg DM/ha without effect on greater values. The CCI was affect by BCSc, Julian calving day (CD) and their interaction (CCI = 191 – (8.6×BCSc) – (0.6×CD) + {0.4×[(BCSc - 4.5)*(CD – 56)]}) (r² = 0.39; P < 0.01; Mean = 121; RMSE = 14). The BCSc mainly explains the CCI confirming his value to predict the reproductive response. Those models contribute to the study of CW and CCI, and could be employed to predict the productive and reproductive response of primiparous beef cows grazing Campos grassland.