Managing and assessing well-being in laboratory mice (Mus musculus) is both challenging and necessary. Assessments intended to detect negative welfare states in mice are usually performed via observation of animals in the home cage, but a substantial amount of time and skill may be required to detect subtle behavioural changes. The Time to Integrate to Nest Test (TINT) is a simple, cageside assessment tool that identifies the presence or absence of a highly motivated normal behaviour in mice. The test is conducted by adding a small amount of new nesting material to a mouse cage. A positive outcome is achieved when this new material is integrated into the home nest within 10 min. This study examined whether housing condition or nesting experience affects TINT outcome. Single or group housing did not influence the TINT outcome, but a significant difference in latency to integration was found; singly housed mice took longer than group-housed mice to integrate TINT substrate. Mice which were raised naïve to nesting material had no significant delays when tested. However, experience with the TINT procedure showed increased speed to incorporate the testing substrate, indicating that previous experience to the paradigm prior to experimental testing may be necessary. These findings help to define the expected outcomes of the TINT, better positioning it for use as an assessment tool in varied research settings.

The aim of our study was to assess the nest-building behaviour of two mouse (Mus musculus) strains using different nesting materials and examine possible sex- and housing-specific effects. Adult mice of two strains (C57BL/6J; n = 64 and BALB/cAnNCrl; n = 99) were randomly allocated to the following housing groups: single-housed male, single-housed female, pair-housed male and pair-housed female. One of the following nest-building materials was placed in each home-cage in a random order: nestlets (Plexx BV, The Netherlands), cocoons (Carfil, Belgium), wooden wool, crinklets and compact (all three, Safe, Germany). The following day, nests were rated applying a nest-scoring scale ranging from 0 to 10, the nests were removed, and a different nest-building material provided. In both tested strains, nestlets achieved the highest nest-building scores when compared to the other four nest-building materials. All nest-building materials scored higher in BALB/c mice compared to C57BL/6J animals reaching statistical significance in crinklets only. Sex comparison revealed that female C57BL/6J mice only scored significantly higher using crinklets than males and BALB/c female mice were rated significantly higher using wooden wool, cocoons and compact than their male counterparts. While pair-housed C57BL/6J animals built higher-rated nests than single-housed mice in the C57BL/6J strain in all five materials tested, the scores were not significantly different in the BALB/c strain. Results of the present study reveal significant strain-, sex- and housing-related influences on the complexity of nests using different standardised building materials. Such observations need to be taken into account when planning the optimal enrichment programme for laboratory animals.

The construction of a suitable farrowing environment is a continuing dilemma: the piglet’s needs must be matched with those of the sow and the farmer during the main phases that constitute farrowing: nest building, parturition and lactation. Difficulties exist in resolving the various conflicts of interest between and within these three parties (e.g. sow v. farmer: space needed for nest building v. space needed to maximise the amount of farrowing accommodation, or sow v. sow: ensuring the survival of the current litter v. maintaining condition for future litters). Thus, the challenge is to resolve these conflicts and design a system that maximises sow and piglet welfare while maintaining an economically efficient and sustainable enterprise. In order to successfully design a farrowing and lactation environment, it is necessary to consider the biological needs of both the sow and her litter. The natural behaviour of the sow has been well documented and very little variation exists between reports of peri-parturient behaviour observed in extensively kept domestic sows and their wild counterparts. The failure for domestication to significantly alter these behavioural patterns provides evidence that they are biologically significant and that the commercial farrowing environment should attempt to accommodate this behavioural repertoire. In addition, the behavioural needs of the piglets, as well as the physiological needs of both sows and their offspring should be considered. This article aims to review the considerable body of literature detailing the behavioural repertoire of sows and their offspring during the different phases of farrowing, and the accompanying physiological processes. The focus is on identifying biological needs of the animals involved in order to synthesise the appropriate design criteria for farrowing and lactation systems, which should optimise both welfare and animal production.

The influence of environmental stimuli considered biologically relevant for nest building sows, on nursing and suckling behaviour and piglet growth was investigated. Effects of floor type (beach sand v. concrete) and substrate type (straw feeder v. no straw feeder) were examined in a 2 × 2 factorial experiment with nine replicates of four multiparous sows. The sows were kept individually in roofed 7·6 m2 ‘get-aw ay-pens’ from 1 week pre-partum until 13 to 15 days post-partum. The behaviour of sows and piglets were video recorded for 24 h on days 0, 3, 6 and 12 post-partum.

The latency from termination of farrowing until perceptible milk ejection tended to be shorter for experienced sows (parity 4 to 5) kept on sand than on concrete floors (1207 (s.e. 109) min; no. = 7 v. 1725 (s.e. 123) min; no. = 6, respectively; F2,8 = 3·93, P < 0·07) and for experienced sows with access to a straw feeder than without access to a straw feeder (1257 (s.e. 113) min; no. = 8 v. 1666 (s.e. 132) min; no. = 5, respectively; F2,8 = 3·56, P < 0·08). On days 3 and 6 a longer duration of suckling was found for sows on sand v. concrete floors (384 (s.e. 20) v. 327 (s.e. 16) s on day 3; F1,19 = 5·6, P < 0.03 and 377 (s.e. 14) v. 318 (s.e. 13) on day 6; F1,21 = 9·09; P < 0·01, respectively) and with straw feeder v. without straw feeder (385 (s.e. 20) v. 326 (s.e. 18) s on day 3; F1,19 = 5·11, P < 0.04 and 372 (s.e. 14) v. 323 (s.e. 13) on day 6; F1,21 = 6·21; P < 0·03, respectively). On day 3, a tendency for a sand × straw feeder interaction (F11,8 = 3·58, P < 0.08), showed that sows without environmental stimuli terminated more sucklings than sows with access to a straw feeder and sows kept on sand (32 (s.e. 7) %, 16 (s.e. 4) % and 13 (s.e. 5) %, respectively). Similarly, on day 6 a significant sand × straw feeder interaction (F316 = 7·15, P < 0·01) led to increased frequency of foreleg rowing for sows without environmental stimuli compared with the three other treatments (14 (s.e. 2) v. 7 (s.e. 1), 5 (s.e. 1) and 6 (s.e. 1) foreleg rowings per h, respectively). During the stay in the experimental pens, the growth rate of piglets kept on sand tended to be higher than for piglets kept on concrete floors (261 (s.e. 33) v. 240 (s.e. 30) g per piglet per day; F1,25 = 3·38; P < 0·08).

The results of the present experiment indicate that provision of biologically relevant stimuli affect the nursing and suckling behaviour of sows and piglets. The reduced termination of sucklings, the reduced frequency of foreleg rowing, the increased duration of suckling as well as the earlier development of suckling behaviour might have been advantageous for the early milk intake of the piglets.