Previous work (Terlouw et al., 1991) has shown that confined sows only developed stereotypies when kept under food restriction. Furthermore, highest levels of stereotypies were found immediately after feeding. The present study tested the hypothesis that stereotypies in food restricted sows are specifically stimulated by food ingestion.

Experiment 1. The experiment was conducted on 13 restrained and food restricted sows (parity: 2; Cotswold Pig Development Co. Ltd, UK), receiving 2.5 kg of a concentrated sow food (13 MJ/kg) at 0900 hrs and that had shown post-meal stereotypic chain manipulation (range 0-300 min/day) and excessive drinking (range 6-50 litres/day) for 7 months. Two treatments were given in the afternoon, when they were generally inactive; 1) novel sound (duration 10 min) 2) unexpected extra meal (approximate ingestion time 10 min). Each treatment was repeated twice, with two treatment days per week. Days preceding treatment days were used as controls. Chain manipulation and drinking were recorded continuously using an automatic logging system.