In various mammals stress during gestation can result in long term effects on the behaviour and physiology of the offspring. The aims of this study were (i) to characterise individual variation among primiparous sows (gilts) in their behavioural and physiological response to a commercially relevant social challenge (mixing with older sows) during gestation and (ii) to determine whether this variation was associated with a corresponding variation in the subsequent effects on the offspring. After assessing dominance in a food competition test, 24 gilts were studied in groups of six during two one-week periods (unmixed – U). These gilts were split into eight subgroups of three gilts, each of which were mixed with two older sows for one week (mixed – M1) before being returned to their original group of six for two weeks. Mixing was then repeated using different older sows during a second week (mixed – M2). Aggressive behaviour, skin lesions and salivary cortisol increase over baseline were higher, and weight gain was lower during mixed periods. During mixing gilts spent more time in feeder stalls, avoiding sows lying in a straw-bedded area, although there was considerable variation among individuals in the extent to which they interacted with or avoided sows. Gilts which interacted more with sows had lower weight gain and higher lesion scores. Previously dominant gilts had higher salivary cortisol increases during mixing. Measures of the impact of mixing, most notably M1 lesion scores, were associated with the behaviour of their offspring: gilts with more lesions had piglets that were less active and less vocal on the day of weaning and over 31 days post-weaning, and were less aggressive over 31 days post-weaning. Thirty-two piglets (from 16 of the gilts) were either restrained for 30min or not restrained prior to euthanasia at 60 days of age. The restrained piglets from gilts with higher M1 lesion scores had higher levels of corticotropin-releasing hormone mRNA in the paraventricular nucleus and amygdala. This study demonstrates that differences between individual gilts in their experience of a stressful social challenge co-vary with the extent to which this pre-natal stress impacts on their offspring.

Pigs are known to be intelligent, social nonhuman animals with specific behavioral, physical, and psychological needs. A considerable amount of research has been conducted to investigate pigs on the farm at every stage of the production cycle in order to better understand the species, not only to maximize profitability for the swine industry but also to improve the lives of the pigs. This book provides a thorough review of key empirical work that has been carried out in the field of pig welfare. The content is intended for “academics, researchers, students, animal welfare associations and anyone involved in the production chain” (back cover). The book opens with two chapters on animal welfare science and its applications. Chapter 1 introduces general welfare concepts and terminology. Chapter 2 focuses on methods of welfare assessment and includes stress physiology and behavior, linking these to production and pathology. Chapters 3, 4, and 5 are specific to on-farm pig welfare. The authors start with the sow and progress to the piglet and the growing-finishing pig. These chapters deal with specific aspects of welfare at each stage of pig production, for example, housing systems for sows, neonatal piglet mortality, and the social environment of newly weaned piglets. Chapters 6, 7, and 8 deal with specific postfarm issues: transport, preslaughter management, and the slaughter process. Complementing each other, these topics

Pre-weaning piglet mortality continues to be a major welfare and economic concern. In outdoor farrowing systems, there is a particular need to broaden breeding goals by incorporating selection for piglet survival to improve both productivity and welfare. This study aimed to identify behavioural and physiological survival indicators that are influential in outdoor systems and that could provide additional information for use when selecting for piglet survival. Data were collected from 511 piglets from Large White x Landrace x Duroc sows and Generalised Linear Mixed Models determined which indicators were most important for piglet survival in an outdoor system. With respect to prenatal mortality (surviving vs. stillborn piglets) high ponderal index (P<0.001) or body mass index (P<0.001) in conjunction with being born earlier in the farrowing birth order (P<0.001) were the most important survival indicators. Birth weight (P<0.001) and rectal temperature 1 h after birth (P=0.032) were the most significant postnatal survival indicators. However survival indicators identified as important in indoor, conventional farrowing crates, such as landmark behaviours (latency to reach the udder, a teat and to suckle colostrum), were not influential in this system. These results highlight the importance of studying potential indicators of survival in alternative farrowing systems to the farrowing crate. (C) 2009 Elsevier B.V. All rights reserved.

This study provides evidence in the pig that stress experienced during gestation has long-lasting effects on offspring daughters, including their maternal behaviour. Thirty-six primiparous sows were divided into control and two groups that were stressed (by social mixing) during either the second (Mix 2) or third (Mix 3) trimester of pregnancy. We found detrimental effects of mixing on the mothers' growth, body lesions, and cortisol secretion, but did not observe any significant effects on reproductive parameters including birth weight. At 60 days of age, 48 daughters were randomly selected from the three treatments: half were challenged using a restraint and isolation test. Then, all were culled and brain tissue was collected. In situ hybridisation measurements showed increased expression of CRH mRNA in the PVN in unrestrained Mix 2 and in the amygdala of Mix 2 and Mix 3 daughters. At 67 days, 24 further daughters were mixed to measure their responses to this social stress. All showed increased salivary cortisol secretion, but Mix 2 and Mix 3 daughters showed a greater and longer response than controls. Finally, all 24 were inseminated and at parturition maternal behaviour was measured. Mix 2 and Mix 3 daughters were more restless and more responsive to piglets that approached the head of the sow, traits which previously have been shown to be a component of abnormal maternal behaviour. Indeed, Mix 2 and Mix 3 daughters also tended to bite at their piglets more than control daughters.

Aggressive behaviour exhibited by domestic pigs following encounters with unfamiliar individuals is a serious welfare and economical problem. Aggression resulting in skin lesions is similarly prevalent in prepubertal pigs of either sex. Little is known about the neural circuits and neuropeptides that control aggression in the pig. Because there is evidence for the involvement of the vasopressin and serotonergic systems in the regulation of aggressive behaviour in male mammals, we sought differences using quantitative in situ hybridisation of vasopressin and serotonin 1A receptor (5-HT1A) mRNA expression within specific brain regions of aggressive and nonaggressive prepubertal female pigs. The number of cells expressing vasopressin mRNA was significantly higher in aggressive pigs in the medial amygdala, lateral septum (LS) and showed a similar trend in the bed nucleus of the stria terminalis (BnST) but not the paraventricular nucleus (PVN) or supraoptic nucleus. The 5-HT1A receptor was widely expressed through the porcine brain and a significantly lower intensity (silver grain density) of 5-HT1A mRNA expression was observed in the BnST. In the medial amygdala and LS fewer cells expressed 5-HT1A mRNA in aggressive pigs but no differences were found in the PVN. In the absence of inbred strains or selection lines, these findings have shown that prior identification of phenotypic behavioural extremes in a population in advance of neural studies is a useful technique. Moreover, these findings support a central role for vasopressin and serotonin in the mediation of high trait aggression in prepubertal female pigs.