Pens for farmed mink (Neogale vison) commonly include separate nesting areas to provide privacy and warmth in the perinatal period. However, standard bedding materials may not be sufficient to allow intrinsically motivated nest-building behaviours in dams. Further, these materials may not produce optimal nest structures for the rearing of kits. In the present study, we provided extra, relatively high-quality nest-building materials and a chewable sisal rope enrichment for mink dams in the perinatal period (a group enriched at whelping; EW). The effects of these enrichments on various measures of welfare and maternal behaviour were compared to those of mink dams in standard housing (SH) and mink dams whose kits were enriched later in development (EK). EW dams performed less stereotypic behaviour and built higher quality nests than dams of other housing conditions, although dams’ basal faecal cortisol metabolite levels (FCM) were not affected. The stress responsiveness of these dams’ offspring was later assessed by sampling FCM before and after a handling event, however, this event did not appear to induce a measurable stress response and thus no conclusions could be drawn regarding effects of perinatal enrichment on HPA-axis development. Overall, provision of higher quality nest-building materials and a chewable rope enrichment benefited dam stereotypic behaviour and nest building in the perinatal period. We present suggestions for future studies to further investigate whether perinatal enrichment can impact maternal care and offspring HPA-axis development in mink.

A single manipulable enrichment is often introduced to the pens of farmed American mink (Neogale vison) to combat stereotypic behaviour and behaviours or temperaments associated with poor welfare (e.g. inactivity, fear, and aggression). This enrichment is provided early in life, but it is unclear the age at which enrichment is most effective at preventing stereotypic behaviour and ameliorating welfare. Here, a group of enriched kits (EK) were provided with multiple enrichments that were periodically exchanged to renew novelty from 4–15 weeks of age, earlier than typical enrichment provision on farms, after which they were housed with a single standard enrichment into adulthood. The effects of EK enrichment on kit behaviours and long-term stereotypic behaviour were compared to that of two groups reared with a single standard enrichment (standard housed; SH and enriched at whelping; EW). Inactivity in the nest-box was decreased in EK kits as juveniles relative to other groups, however, social play was reduced and lying awake was increased compared to EW and SH juveniles, respectively. Stereotypic behaviour in the kits as adults was not prevented by EK interventions; in fact, EK kits may have developed more diverse sub-types of stereotypic behaviour than EW and SH kits. Moreover, kit temperament did not appear to be affected. EK enrichment may have been ineffective in improving welfare due to the timing of its removal or potential frustration induced by its removal. Recommendations are provided for future research regarding critical periods of enrichment to improve welfare in species such as farmed mink.

The East Flanders Prospective Twin Survey (EFPTS) is a registry of multiple births in the province of East Flanders, Belgium. Since its start in 1964, over 10,000 twin-pairs have been registered. EFPTS has several unique features: it is population-based and prospective, with the possibility of long-term follow-up; the twins (and higher order multiple births) are recruited at birth; basic perinatal data are recorded; chorion type and zygosity are established; since 1969, placental biopsies have been taken and frozen at –20°C for future research. Since its origin, the EFPTS has included placental data and allows differentiation of three subtypes of monozygotic twins based on the time of the initial zygotic division: the dichorionic–diamniotic pairs (early, with splitting before the fourth day after fertilization), the monochorionic–diamniotic pairs (intermediate, splitting between the fourth- and the seventh-day postfertilization) and the monochorionic–monoamniotic pairs (late, splitting after the eighth day postfertilization). Studies can be initiated taking into account primary biases, those originating ‘in utero’. Such studies could throw new light on the consequences of early embryological events and the gene–environment interactions as far as periconceptional and intrauterine environment are concerned.

The aim of this study was to analyse the relationship between childhood socioeconomic conditions and body asymmetry in young Polish women. The study measured fluctuating asymmetry (FA), which refers to small random deviations from perfect symmetry in bilaterally paired body structures. Data were obtained from 620 female students aged from 19 to 25 years recruited from Jagiellonian University in Cracow, Poland. The research was carried out in the period from January 2016 to May 2017. A composite fluctuating asymmetry (cFA) of the women was calculated using five bilateral body traits. The lengths and widths of the women’s ears, lengths of their 2nd and 4th digits and wrist widths of the right and left sides of the body were measured twice using standard methodology. The following data were collected in a questionnaire: degree of urbanization of the woman’s place of residence during childhood, number of older siblings, parental education and woman’s dominant hand. The results showed a tendency for FA to fall with an increase in parental education, and to rise with an increase in number of older siblings. The level of FA was significantly lower in women from rural areas than in those from cities. The results of the study show that FA in early adulthood is significantly associated with socioeconomic status during childhood, and confirm that the level of FA in adulthood may be a good indicator of stress factors in the early stages of development.