The study examined the effects of housing 24 adult female pigs in groups of 2, 4 or 8 with a space allowance of 1.4msuperscript 2 per pig on welfare status, as indicated by plasma free-corticosteroid concentrations and behaviour patterns, and sexual behaviour. Housing gilts in pairs resulted in an increase in free corticosteroid concentrations (measured 11 and 84 days after the start of the treatments) and an increase in the number of observations of lying behaviour without physical contact with another pig (recorded 21 days after entering the treatment) compared to housing in groups of 4 or 8. Overall mean free corticosteroid concentrations were 31. +or- 0.29, 2.3 +or- 0.26 and 1.9 +or- 0.12 ng ml-1, and the mean numbers of observations of lying-alone behaviour (out of a total of 88 observations) were 6.4, 3.6 and 1.9 for gilts housed in groups of 2, 4 or 8, respectively. Although there were no differences between treatments in agonistic behaviour around the time of feeding, these data suggest there are undefined social stressors in pigs housed in pairs. Housing treatment had no significant effects on sexual behaviour. However, the mating rate was low in all treatments, possibly owing to sub-optimal space allowance.
|Publication Title||Applied Animal Behaviour Science|
|Author Address||Anim. Res. Inst., Werribee, Vic. 3030, Australia.|
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