The dopamine systems In the brain are strongly involved in motor activity. Pharmacological stimulation of brain dopamine systems with dopamine agonists initially results in increased levels of motor activity that with increasing doses become more stereotyped in form. It has been suggested that in tethered sows, stereotypies develop because chronic environmental stress produces activation of brain dopamine systems (Dantzer, 1986). Furthermore, differences In the sensitivity of brain dopamine systems may form the basis of the large individual variation found in level of stereotypies (Segal and Kuczenski, 1987). Manipulation of the chain forms the major category of stereotypic behaviour during long term tethering. In addition, many pigs develop excessive drinking (Terlouw et al., in press). The present study investigated whether female nulliparous pigs differed in their response to a standard dose of amphetamine and whether this response is correlated to the amount of chain activity and drinking that developed during subsequent long term tethering.