Review articleThe effects of environmental enrichment on the behaviour of suckling piglets and lactating sows: A review

The aim of this paper is to review the existing literature concerning environmental enrichment for suckling piglets and lactating sows and the effects on behaviour and mortality. Most research considering environmental enrichment still focuses on weaner, grower and finisher pigs. However the European Union Directive 2001/93/EC states that all pigs should have access to a sufficient quantity of material to enable proper investigation and manipulation activities. Fortunately, research on environmental enrichment and alternative housing for piglets and sows is growing and results show important beneficial effects on welfare of both piglets and sows, by providing opportunities to engage in explorative behaviour, nest-building and social interactions and improving maternal responses. Social enrichment, increased space allowance and/or straw provide promising results on welfare but are not always practical to implicate and bring forth other potential risks and concerns. Therefore, it would also be interesting to further examine the potential of other types of enrichment, such as objects or sensory enrichment (e.g. pheromones), as possible applications and their effects on piglet and sow welfare. Other aspects which need more clarification are the relation between environmental enrichment during the farrowing period and weaning age and the relation between painful procedures, such as castration and tail docking, and environmental enrichment on the behaviour of piglets.