Behavioural and psychological needs of laboratory animals generally cannot adequately be met in standard laboratory cages. Environmental enrichment, which provides a more structured environment can enhance the well-being of laboratory animals. They may perform more of their species-specific behaviour and may control their environment in a better way. An easily applicable form of enrichment for laboratory mice is nesting material. Six different types of nesting materials were evaluated in a preference test with male and female animals of two strains (C57BL/6J or BALB/c, n=48). No significant differences in preference were found between the strains or between the sexes. All mice showed a clear preference for cages with tissues or towels as compared to paper strips or no nesting material, and for cages with cotton string or wood-wool as compared to wood shavings or no nesting material. Paper-derived materials were preferred over wood-derived materials, although the results also suggest that the nature (paper or wood) of the nesting material is less important than its structure, which determines the nestability of the material. Nesting material may be a relatively simple method to contribute to the well-being of laboratory mice.

The present study compared the performance and development of adverse behaviours of pigs with intact tails, when housed in a straw-bedded system or a part-slatted system enriched with a commercial device. The pigs had previously received different enrichment treatments (rooting box, liquid dispenser, straw bedding or none), either in the farrowing crate or with their lactating dam or post weaning. The pigs were mixed in groups at 10 weeks of age and from then on, every 2 weeks, behavioural observations were performed, focusing mainly on harmful social behaviour and enrichment use. The study showed that pigs with undocked tails can be at high risk of tail biting in part-slatted systems, whereas the straw bedding prevented the development of tail biting. The immediate effects of the environment seemed to exert a greater influence on the development of adverse behaviour than early life enrichment and adding a simple enrichment device could not compensate for the deficiencies in the barren environment of the part-slatted system. In order to prevent vice, functional design of environmental enrichment is required.