It has recently been shown that stereotypies In tethered sows are reduced at high feeding levels, Indicating that feeding level may be a major factor in the development of stereotypies (Appleby and Lawrence, 1987). It has also been suggested that the restraint of tethering Itself Is a major source of stress for the sow, thus promoting the development of stereotypies. The exact role of both factors of feeding level and restraint on the development of stereotypies have not yet been studied separately.

Differences in experimental environments and genotypes may explain part of the large variability in levels stereotypies previously observed in tethered sows across experiments. Differences in stereotyped activities between sows of the same genotype within experiments must, however, be explained by individual differences In sows’ behavioural and neurological profiles.

The present experiment investigated the role of restraint and feeding level on the development of stereotypies in pregnant gilts. Secondly it Investigated social temperament as a factor reflecting the gilts’ predisposition to develop certain abnormal behaviours.