Limb injuries, immune response and growth performance of early-weaned pigsin different housing systems

The welfare of early-weaned pigs in different housing systems was examined using a range of indicators. Three replicates of 20 pigs were weaned at 6.4 kg live weight into either: (a) deep-straw; (b) Straw-Flow(R); (c) large f latdeck; (d) small flatdeck. A kenneled Eying area was provided in (a) and (b). The floor in (c) and (d) was expanded metal. Stocking densities were 0 .23 m(2) per pig in (a), (b) and (c) and 0.17 m(2) per pig in (d). After 4 to 5 weeks (19.6 kg live weight), 16 pigs from each pen were moved into Str aw-Flow grower pens (0.68 m2 per pig) and observed until slaughter at 90.6 kg. The remaining pigs were grouped together to examine the effects of mixi ng. At weaning, 24.1% of pigs had foot injuries. Pigs with foot injuries re covered quickly on deep-straw but the injuries increased in flatdecks immed iately after weaning (Straw-Flow was intermediate). Injuries were more pers istent in the small flatdeck. Deep-straw prevented adventitious bursitis of the hock. After 1 month in the grower pens, there was no residual treatmen t effect. Antibody response was examined by immune challenge with keyhole l impet haemocyanin (KLH). Immunoglobulin (Ig) response was greater in straw pens. Pigs mixed at 20 kg showed a decreased immune response to KLH challen ge. Growth and food intake showed no treatment effects; food conversion rat io was poorer in (c) than in (b) or (d).