Besides having major functions in ensuring successful parturition, and nutrition and care of the offspring, oxytocin is involved in the regulation of behavioural and physiological stress responses in the brain. To investigate the neurobiological basis of individual differences in stress responses in cattle, we examined the association of behavioural and hypothalamo-pituitary-adrenal axis reactivity to acute stressors and plasma oxytocin levels. Twenty Holstein heifer calves aged 2 weeks were subjected to a 10-minute open-field test followed by presentation of a feeding bucket for 15 min in the open field. If the calf contacted the bucket, a blast of air was applied to its muzzle (surprise test). Jugular blood samples collected before and after testing, via indwelling jugular catheters, were analyzed for oxytocin and cortisol. Because of insufficient volume of samples, the plasma oxytocin concentration could be measured for only 9 animals out of 20. Relationships of basal and percent change in oxytocin with behavioral responses in each test and percent change in cortisol were analyzed using principal components analysis and Spearman rank correlations. Plasma cortisol concentration was significantly elevated by the tests (p < 0.005). Four principal components explained 56.1% of the total variation: curiosity, general activity, fearfulness and dependence on humans. Curiosity was inversely correlated with basal oxytocin level (rS = -0.683, p < 0 .05). General activity was inversely correlated with percent change in oxytocin (rS = -0.717, p < 0.05). Fearfulness tended to correlate positively with basal oxytocin level (rS = 0.583, p < 0.1). Dependence on humans correlated with none of the hormonal parameters. These results likely reflect relationships between individual differences in stress responses and basal oxytocin level in cattle.