Alternative housing for sows and litters: 2. Effects of a communal piglet area on pre- and post-weaning behaviour and performance

We conducted an experiment to determine how allowing piglets access to a communal area affects pre-weaning and post-weaning behaviour and performance. Litters were housed in pens with sows in crates until piglets reached 11 days of age. For 10 experimental cohorts, barriers between the pens of three litters were removed allowing piglets to mingle freely in a central area. For the 10 control cohorts (also three litters each), litters were not allowed to mix before weaning. There was little aggression when experimental litters were allowed to mix, and piglets played and rested in mixed-litter groups. Time spent in the common area increased from approximately 20% just after mixing (12 days old) to approximately 45% at day 26 (week 4; P < 0.001). Experimental piglets were nursed less often than controls,,especially during the later stages of lactation (P < 0.01). However, there was no difference in the amount of creep feed consumed or rate of weight gain before weaning. After weaning, experimental piglets ate more solid food than controls (approximately 70 g/day more during the second week after weaning, P < 0.05), and showed a non-significant tendency to gain more weight (approximately 50 g/day). As a second comparison, piglets were either kept in single litter groups after weaning, or mixed with other litters from the same cohort. When control litters were mixed after weaning, piglets spent almost 60% more time in aggressive behaviour than when litter-mates were kept together, but no such difference occurred for the experimental litters (interaction P < 0.05). Thus, the experimental housing treatment allows for mixing at an early age (much as occurs in nature) with little apparent conflict, provides piglets with a socially enriched pre-weaning environment, and helps avoid fighting between mixed piglets at weaning. The system also slightly lowers demands on the sow during lactation (in terms of a reduced nursing frequency) and slightly increases intake of solid food by piglets after weaning. (C) 1999 Elsevier Science B.V. All rights reserved.