Effect of cage enrichment on the stereotypic behaviour of commercially kept pregnant sows

Abstract

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.