In a semi-natural environment, a lot of t
he daily activity of pigs is spent in exploratory and foraging be
haviour. Providing enric
hment material attractive to t
he pigs bot
h over t
he s
hort and long term is t
herefore important in intensive
housing systems. T
his study aimed to investigate t
he effect of four types of point-source enric
hment materials and four types of litter on t
he be
haviour of finis
hing pigs. In experiment 1, pigs were offered cut straw or cut straw enric
hed wit
h maize kernels as litter on t
he lying area, as well as a cylindrical dispenser filled wit
h a compressed straw block or a straw rack filled wit
h cut straw. In experiment 2, c
hopped straw or c
hopped
Miscanthus giganteus was provided as litter on t
he lying area, along wit
h a straw-pellet dispenser or bark compost in a troug
h. In bot
h experiments, 96 finis
hing pigs wit
h undocked tails were
housed in groups of six pigs in pens wit
h partly-slatted floors. Half of t
he groups were fed restrictively, t
he ot
her
half ad libitum. Every t
hree weeks, t
he enric
hment materials were replaced. Exploratory be
haviour directed towards t
he enric
hment material, t
he pen equipment and pen mates was videorecorded and analysed by means of one-minute focal-scan sampling on t
he second and eig
hteent
h day after provision of a new enric
hment material. Data were analysed using linear mixed-effect models.
In both experiments, the frequency with which the enrichment material was explored was influenced by the interaction of type of material and day (p < 0.001). On the second day after provision of enrichment, the favoured material was cut straw enriched with maize kernels in experiment 1, and the straw-pellet dispenser in experiment 2. On day 18, straw as litter with or without maize, the straw rack, chopped straw, chopped Miscanthus giganteus and the pellet dispenser were used with a similar, and still relatively high, frequency. The least-explored materials were the straw block and bark compost. In both experiments, pigs fed ad libitum explored the materials less than half as frequently as those fed restrictively (p < 0.001). Manipulation of the pen showed a pattern inverse to that of manipulation of the material, but a similar pattern with respect to feeding regime. Materials had no discernible influence on the manipulation of pen mates. In conclusion, our results indicate that both the point-source enrichment and the litter materials provided constituted adequate enrichment for small groups of finishing pigs.