An investigation of the effect of environmental enrichment and space allowance on the behaviour and production of growing pigs

Both enrichment of the environment and increasing space allowance result in a reduction in nosing and tail biting behaviour among growing pigs. The aim of this study was to identify which factor, enrichment or space allowance, had more influence on pig behaviour. A five treatment randomized block design with four replicates was used. Newly weaned 6-week-old pigs in groups of six littermates were placed in enriched environments with allocated floor space on Treatments 1 to 4 of 0.5, 1.1, 1.7 or 2.3 m(2) per pig, respectively. Treatment 5 was identical to Treatment 4, except for the absence of enriching elements which included free access to the substrates peat and straw. The pigs remained in these environments for 6 weeks and were fed ad libitum. Two focal animals (1 boar and 1 gilt) per group were each observed for 10 min twice per week. The ethogram used attempted to record the full behavioural repertoire of the growing pig. The results show that there was less exploration of substrates and more inactivity in Treatments 1 and 5 than in the other three treatments (P < 0.05), Pigs demonstrated more locomotory behaviour when given greater floor space in enriched pens (P < 0.05). Duration of harmful social behaviour was greater in the barren treatment than in the four enriched treatments (P < 0.01). Production performance, measured by weight gain and feed conversion efficiency, tended to be better in Treatments 1, 2 and 3 indicating that increasing space allowance beyond 1.1 m(2) per pig was not beneficial. From this study it is concluded that enrichment played a greater role in determining pig behaviour than floor space allowance.