Effect of cage enrichment on the stereotypic behaviour of commercially kept pregnant sows
Summary
In this study, the effect of cage enrichment on the welfare of commercially kept pregnant sows
and the possibilities to improve welfare were investigated. Forty-eight sows were observed.
Twenty-for got an enrichment (a chain); the other twenty-four sows formed the control group.
The behaviour of the sows was observed for five weeks, in order to determine both acute and
long-term changes. The behaviour was scored with a scanning method. Before the
intervention, the sows were spending 31.05±2.63% (enrichment) and 33.65±3.10% (control)
of the observation time with stereotypic behaviour. When the chain was hanging low the
enrichment sows showed 5.75% less stereotypic behaviour (p<0.05), a decrease of 19%
regardless on which moment the observations where done (acute versus long-term effects).
When the chain was low, the sows spent 25.05±2.08% of their time manipulating the chain
versus 9.71±2.68% less (p<0.05) when it was hanging high. The interest in the toy
disappeared in course of time with 7.05±2.68% (p<0.05).
The conclusion is that if a chain is used as a toy for individually kept pregnant sows, it might
be a better solution to mount it near the floor of the cage; this because it comes closer to the
natural foraging behavior of pig. It is difficult to state that a chain is useful as a toy to improve
welfare of individually kept pregnant sows. However, considering the amount of time the sows
spent with manipulating the chain, it is a cost–effective device. Furthermore, it was successful
to reduce the amount of stereotypic behaviour of the sows for the period the observations
were done.