Influence of regrouping strategy on performance, behaviour and carcass parameters in pigs

One thousand two hundred pigs were weaned at 4 weeks of age and mixed to form groups of ten animals that were balanced for gender. The groups consisted of uniform weight groups (i.e. separate groups of small, medium or large pigs), or mixed weight groups (i.e. groups containing small, medium and large pigs). Half of the groups were retained from weaning until slaughter at 21 weeks of age, and half were regrouped at the start of the finishing period at 10 weeks of age. In this regrouping, uniform weight groups were regrouped to form mixed weight groups, and mixed weight groups were regrouped to form uniform weight groups. In addition, some mixed weight groups were regrouped to form mixed weight groups in order to assess the effect of regrouping at 10 weeks of age on performance and aggressive behaviour.