We hypothesized that cows grazing stockpiled tall fescue (STF) during late gestation have greater nutrient intake than cows fed summer-baled hay, which would result in increased prenatal nutrient supply and ultimately improved fetal development and subsequent postnatal performance. Forty-eight multiparous, spring-calving crossbred beef cows (683 + 16 [SE] kg BW) were allocated by BW, BCS, age, and expected calving date to either strip-graze endophyte-infected STF (59.7% NDF, 12.3% CP; DM basis; n = 4 pastures) or consume ad libitum endophyte-infected tall fescue hay (HAY; 64.9% NDF, 6.2% CP; DM basis) in uncovered drylots (n = 4) beginning on d 188 ± 2 of gestation. Cows remained on their respective forage systems until calving, but STF cows were moved to drylots at 7.0 ± 1.0 d pre-calving and fed ryelage (58.6% NDF, 12.3% CP; DM basis). Within 1 wk postpartum, cow-calf pairs were moved to a single pasture for common pre-weaning management. At 52 ± 0.6 h and 83 ± 1 d postnatally, calf jugular blood samples were obtained for determination of serum blood urea nitrogen (BUN) and plasma glucose. Data were analyzed using a mixed model containing effects of forage system, sampling day, and their interaction, where sampling day was used as a repeated measure. Pasture or drylot was included as the experimental unit; calf date of birth and sex were included in the model when P < 0.25. We have previously reported that calves born to cows consuming STF tended to weigh more at birth and d 80. There was a tendency (P = 0.07) for a forage system × day interaction for serum BUN concentrations. At 52 h postnatally, calves born to cows consuming hay had decreased (P = 0.02) serum BUN compared with STF, but BUN did not differ (P = 0.95) between forage systems at 83 d of age. Treatment did not affect (P ≥ 0.20) plasma glucose concentrations. Despite this, calves had greater (P < 0.001) glucose concentrations at 52 h then at 83 d. In conclusion, neonatal calves born to cows grazing STF had increased circulating BUN, which may indicate increased perinatal nutrient supply.