THE EFFECTS OF STRAW BEDDING ON THE FEEDING AND SOCIAL-BEHAVIOR OF GROWING PIGS FED BY MEANS OF SINGLE-SPACE FEEDERS

Single-space feeders used in pig selection may favour those pigs which control access to the feeder. This was not the case when straw beddin g was provided (Nielsen et al. 1995). However, straw may have modified behaviour and masked the effects of aggression. Therefore an experime nt was conducted to examine the influence of straw bedding on behaviou r and performance of pigs fed via a single-space feeder. The food inta ke, growth rate, feeding and social behaviour of 8 pens of 10 pigs (st art weight 40 kg) with or without straw (4 pens/treatment) were record ed over a period of 35 days. Food was supplied by one single-space com puterised feeder in each pen and this equipment provided records of fe eding behaviour. Social behaviour and activity was observed by video r ecording on two occasions in week 2 and week 4 of the experiment. Each pen had an enclosed kennel. The provision of straw increased the numb er of visits to the feeder (13.11 vs. 9.22; P < 0.05) and these were o f a shorter duration (4.34 vs. 6.18 min; P<0,05). The pigs on straw ha d a higher growth rate than those without (803 vs. 741 g/d; P < 0.05). Pigs with straw had a lower proportion of observations in the kennel (0.470 vs. 0.683; P < 0.001) and spent less observations lying (0.765 vs. 0.806; P < 0.05). The number of aggressive incidents initiated was higher with straw (14.8 vs. 8.8; P < 0.05). The modified feeding patt ern with straw may have been due to a higher general level of activity or a combined effect of low ambient temperature and the position of t he feeder relative to the kennel. Thus this effect of straw may be con fined to cold environments. (C) 1998 Elsevier Science B.V. All rights reserved.