The effects of pregnancy and parity number on behavioural and physiological responses related to the welfare status of individual and group-housed pigs

摘要: Abstract Plasma free-corticosteroid concentrations, aggressive behaviour and motivation to socially interact explore a novel environment were observed in 39 female pigs housed either groups of 4–7 animals or tether stalls over 2 parities. Gilts tethers their first pregnancy had significantly higher concentrations compared non-pregnant gilts group 7 (4.1, 2.9 3.0, ng ml −1 , respectively). A significant difference was also found between group- tether-housed at the second (2.6 4.7, respectively), but there no effects previous experience parity number. The chronically elevated associated with reduced immunological reactivity (72 48% reductions IgM IgG response 8 days after challenge, respectively) tether- group-housed pigs. In standardized tests, social interaction, not exploration, tether-compared sows both pregnancies. tethers, proportion interactions adjacent these involved retaliation (25 vs. 0%) animals. It concluded that unresolved aggression may result chromic stress adverse on welfare status. effect design stall divisions nature level warrants investigation.