Dystocia is considered painful and stressful for both the dam and the calf, although systematic evidence of this is limited. Few studies have investigated biochemical markers of stress and pain postpartum and whether any adverse effects are ameliorated by administration of analgesia. In this study, cow–calf pairs experiencing both mild to moderate farmer assistance and no assistance at parturition were randomly assigned to either treatment or placebo group in a two-by-two design (animals subject to veterinary intervention were excluded). The treatments were the NSAID ketoprofen or saline, administered within three hours of parturition. Blood samples taken in the immediate postpartum period, and at 24 hours, 48 hours and 7 days after parturition, were analysed for plasma concentrations of creatine kinase and cortisol (cows and calves) and plasma L-lactate and total protein concentration (calves). Stress biomarkers were highest in the immediate postpartum period and declined over time (P<0.05). Cow plasma cortisol was higher in animals experiencing assisted parturition in the immediate postpartum period (P=0.023); by 24 hours no difference was evident. Intervention with NSAID analgesia did not result in beneficial changes in stress biomarkers. Based on biomarkers alone, this suggests limited benefits of NSAID treatment in unassisted or mild to moderately assisted parturition.