Understanding individual differences in temperament traits enables us to investigate the relationship between those traits with animal production and welfare. One aspect of dairy cow temperament that is particularly important to study is aggression. Stress caused by aggressive interactions can negatively affect behaviour and feed intake (Olofsson, 1999), and cause some cows to alter their feeding times to avoid aggressive interactions (Miller and Wood-Gush, 1991). The objective of this study was to characterise the competitive ‘style’ of individual cows. The following questions were addressed: 1) are cows consistent in how they express aggression over time at a standard length feedface, 2) does the parity, feedface length, stage of lactation and social dominance rank have an effect on aggressive behaviour?