Search

• The sow's role beyond nutrition is, in commercial pig production, largely ignored. • We investigated how maternal characteristics contribute to offspring outcomes. • Sows with lower cortisol concentrations showed better nursing behaviour. • Piglets from sows with lower cortisol concentrations grew better. • Reducing sow stress during lactation improves sow and piglet performance and welfare. The importance of maternal care in commercial pig production is largely ignored. The sow has little possibility to interact with her piglets, and piglets are often subjected to early weaning or artificial rearing. This study aimed to investigate aspects of physiological and behavioural maternal provisioning that contribute to offspring outcomes. We hypothesised that better maternal care and nutritional provisioning would relate positively to piglet immunity, growth and behaviour. Nineteen sows and their litters were studied in free-farrowing pens. Oxytocin and tumour necrosis factor-α in colostrum/milk and salivary cortisol were sampled from sows throughout lactation. Sows were assessed for dominance rank, response to handling, maternal defensiveness, suckling initiation and termination, posture and sow-piglet contact. Piglets were weighed, measured for body mass index (BMI) and sampled for blood (Immunoglobulin G; at birth). After weaning, they experienced a human approach test (HAT) and novel object test. Correlations were explored between individual sow characteristics, individual piglet outcomes, and between sow characteristics and piglet outcomes averaged by litter. Significant correlations between sow and piglet factors were analysed at the litter level in mixed models with piglet outcomes as response variables and sow characteristics as predictor variables, while accounting for sow parity, litter size and batch. Litters grew faster when their sow had lower cortisol values (P = 0.03), while sows with lower cortisol levels had more successful suckling bouts and engaged in greater amounts of sow-piglet contact. Litters had a lower BMI at weaning when the sow had a higher milk fat percentage at d3. Litters of the most dominant sows took longer to approach the human in the HAT, while litters of sows with higher cortisol at d0 took longer to approach the novel object when assessed on correlations (r = 0.82, P < 0.001) but not when the model accounted for parity and litter size (P = 0.35). Only some of the measured nutritive and non-nutritive sow factors influenced litter performance and behaviour, with parity and litter size also playing a role. Given the continued increase in litter size, but also the interest in loose-housed lactation pens for sows, further research on sows' maternal investment and how it can be optimised is warranted. [ABSTRACT FROM AUTHOR]

Abstract: Extensively managed animals, often living in harsh and unfavourable environments, need specific adaptations that promote survivability. This is particularly important at parturition and during the neonatal period, when ewe and lamb mortality is highest. To understand the survival adaptations of extensively managed breeds, we reviewed the behavioural and physiological adaptations of ewes and lambs of hill (extensive) breeds of sheep to lowland (intensively managed) breeds during pregnancy, parturition and lactation. Hill sheep have a smaller average litter size than lowland sheep but carry a significantly heavier litter (proportional to their own body weight), which may be achieved through more efficient placental exchange. Isolation seeking at parturition by the ewe is affected by maternal experience and familiarity with the environment. However, an increase in domestication and intensification appear to have led to a decrease in isolation seeking at parturition. Hill ewes have a shorter labour, and an easier delivery than lowland ewes, which may be partly related to pelvis dimensions and to lamb characteristics. Hill ewe breeds lick their newborn lambs more than lowland ewes immediately after birth, and have a higher rate of low-pitched bleating (both important behaviours for the development of ewe–lamb attachment). These behavioural differences result in better ewe–lamb recognition 24h after birth in hill ewes, and closer ewe–lamb spatial relationships during lactation. Hill ewes are more aware of the presence of their lambs during lactation, which may aid defence of the lamb against predators. Hill lambs are quicker to stand and suck after birth than lowland lambs, and show better maternal recognition than lowland lambs. Hill lambs also maintain higher rectal temperatures after birth than lowland lambs and have better cold resistance. Better thermoregulation is partly related to birthcoat characteristics, but is also accompanied by higher thyroid hormone concentrations (important for endogenous heat production) in hill than lowland lambs. The colostrum of hill ewes has higher lipid content than lowland ewes, which may also contribute to improved thermoregulation. This suggests that hill sheep, adapted to extensive management systems, have evolved more efficient behavioural and physiological mechanisms to enhance lamb survivability in harsh environments than have intensively managed lowland sheep breeds. [Copyright &y& Elsevier]

Maternal undernutrition in pregnancy results in low birth-weights and impaired postnatal survival in sheep. Largely anecdotal evidence suggests that the expression of appropriate maternal and neonate behaviours may also be disrupted by undernutrition. In the present study, we investigated the effect of a moderate (35 %) reduction in ewe nutritional intake in pregnancy on the expression of ewe???lamb bonding behaviours in primiparous Scottish Blackface ewes. Low-intake (L) ewes had significantly higher plasma progesterone than high-intake (H) ewes from mid-gestation onwards (e.g. plasma progesterone at 20 weeks (n/l): H 15??72, L 22??38, SED 1??80, P<0??001), AND A LOWER OESTRADIOL: PROGESTERONE VALUE THAN H EWES AT DELIVERY (H 0??46, L 0??35, sed 0??05, P<0??05). Lamb birth-weight was reduced in the L lambs compared with H lambs (mean body weight (kg): H 3??31, L 3??00, sed 0??14, P<0??05), but the incidence of malpresentation at delivery was greater in L lambs. L ewes spent significantly less time licking their lambs than H ewes after delivery (time grooming in 2 h after birth (%): H 56??12, L 48??17, sed 2??639, P<0??01) and were more aggressive towards the lambs. Lamb behaviours were not directly affected by maternal nutritional treatment, but lamb birth-weight had a significant effect on neonatal developmental progress. Low-birth-weight lambs were slower than heavier lambs to stand and sucked less frequently. In tests of maternal attachment to the lamb, H ewes received higher scores than L ewes at both 24 h after birth (ewes receiving high scores (%): H 41??3, L 21??4, P<0??05) and at 3 d postnatal. We conclude that even a moderate level of undernutrition impairs the attachment between ewes and lambs by affecting maternal behaviours expressed at birth. In addition, the results suggest that levels of nutrition resulting in a decrease in birth weight will affect neonatal lamb behavioural progress. [ABSTRACT FROM PUBLISHER]

Abstract: Consistent, individual differences in the expression of maternal behaviour have been described in several species including the sheep. The neuroendocrine mechanisms underlying the onset of maternal behaviour in the sheep have been described, although the relationship between hormonal events and individual differences in behaviour has yet to be determined. In this study, we examined whether the individual differences in plasma estradiol, progesterone, oxytocin and cortisol concentrations were related to observed individual and breed differences in maternal behaviours in two breeds of sheep (Scottish Blackface and Suffolk) known to differ in maternal behavioural expression. Maternal estradiol concentration increased rapidly before parturition and was higher in Blackface ewes than Suffolk ewes. Plasma progesterone declined before parturition and was higher in Suffolk than Blackface ewes. Prepartum estradiol, but not progesterone, was related to individual differences in maternal grooming of the lamb. Plasma oxytocin did not differ between breeds in late gestation. There was a tendency for oxytocin to be higher in Blackface than Suffolk ewes immediately after birth. However, there were no significant relationships between prepartum or postpartum oxytocin and any maternal behaviours. Plasma cortisol was higher in Blackface than Suffolk ewes in the last days of pregnancy but rose in both breeds over the last 24 h before parturition and did not differ at delivery. Cortisol peripartum was negatively related to individual differences in maternal affiliative behaviours. These data suggest that estradiol, and potentially cortisol, may mediate individual differences in maternal behaviour in sheep. [Copyright &y& Elsevier]

Piglet-directed aggression by farrowing pigs seriously threatens the welfare of the piglets and also results in economic waste within the pig industry. Pre-weaning piglet mortality in the UK is around 11% with savaging accounting for up to 25% of deaths. The aim of this study was to investigate whether gilts that savage piglets behave differently to non-savaging gilts during the expulsive phase of parturition. The behaviour of the gilts during the 8 h following the birth of the first piglet was recorded. The gilts were categorised as savagers (n=4) or non-savagers (n=15) depending on their response to piglets during farrowing, and then behaviour during farrowing was compared between the two groups. The maternal behaviour during the first 8 h of farrowing differed significantly between the savagers and non-savagers. Savaging gilts were significantly more restless and more responsive towards their piglets during farrowing as characterised by increased posture changing, higher frequency of walking and time spent investigating piglets that approached their head. Overall the results of this study suggest that aberrant maternal behaviour during farrowing involves increased restlessness and responsiveness to piglets, particularly in the early stages of the expulsive phase, which are opposite to the inactivity and passivity suggested to reflect good maternal care in the pig. It is suggested that this restlessness and responsiveness of savaging gilts may not necessarily reflect poor maternal ability, but may be related to the individual’s inability to cope with restrictive environments around farrowing. [Copyright &y& Elsevier]

Abstract: Numerous studies have shown that prenatal stress (PNS) can have profound effects on postnatal well-being. Here, the domestic pig (Sus scrofa) was used to investigate PNS effects owing to the direct relevance for farm animal welfare and the developing status of the pig as a large animal model in translational research. Pregnant primiparous sows were exposed, in mid-gestation, to either a social stressor (mixing with unfamiliar conspecifics) or were kept in stable social groups. The ratio of levels of mRNAs for corticotropin releasing hormone (CRH) receptors 1 and 2 in the amygdala, measured for the first time in the pig, was substantially increased in 10-week-old female, but not male, PNS progeny indicating a neurobiological propensity for anxiety-related behaviour. Mature female offspring were observed at parturition in either a behaviourally restrictive crate or open pen. Such PNS sows showed abnormal maternal behaviour in either environment, following the birth of their first piglet. They spent more time lying ventrally, more time standing and showed a higher frequency of posture changes. They were also more reactive towards their piglets, and spent longer visually attending to their piglets compared to controls. Associated with this abnormal maternal care, piglet mortality was increased in the open pen environment, where protection for piglets is reduced. Overall, these data indicate that PNS females have their brain development shifted towards a pro-anxiety phenotype and that PNS can be causally related to subsequent impaired maternal behaviour in adult female offspring. [Copyright &y& Elsevier]

Abstract: There is growing external pressure to abolish the farrowing crate, however alternative farrowing systems need to equal or surpass the performance (i.e. piglet survival) of more restrictive systems. In order to achieve consistent improvement in piglet survival genetic selection strategies targeting specific survival traits could be used. One of the key components of survival in alternative, loose-housed farrowing systems is maternal behaviour and understanding the characteristics of sows that influence survival in such environments should be an essential component when developing new breeding indices. In this study 65 gilts and their piglets (757) from two genetic selection lines, High postnatal Survival (HS) or Control (C), were studied in both indoor loose-housed and outdoor farrowing systems. The influence of genetics and environment on piglet survival and maternal characteristics was studied. Genotype affected total mortality at a piglet level in the outdoor system (C: 17.90% (±3.23) vs. HS: 12.21% (±3.46) W 1 =3.60, P =0.058), but there was no effect in the indoor loose-housed environment (C: 12.29% (±2.69) vs. HS: 14.86% (±3.18) W 1 =0.07, P =0.797). Genotype influenced maternal characteristics, with C gilts in both environments being significantly more likely to crush their piglets when changing posture during farrowing (Mean deviance ratio1,62 =47.25, P =0.002). High Survival gilts in the indoor environment were aggressive towards their offspring, and were the only genotype to display savaging behaviour (Mean deviance ratio1,62 =64.90, P <0.001). This suggests a genetic effect on environmental sensitivity and thus, in order to make effective improvements it is important to estimate genetic parameters (both behavioural and physiological) under the conditions in which the animals will be kept. [ABSTRACT FROM AUTHOR]

Abstract: 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. [Copyright &y& Elsevier]