Enriching sow environment and diet during gestation reduced piglet neonatal mortality

Sow environment during gestation can generate maternal stress which could influence piglet health and survival after birth. The study aimed to investigate a strategy of environmental and nutritional enrichment to reduce maternal stress and its consequences on piglet mortality. Gestating sows were group-housed in a conventional system on a slatted floor (C, n=26), in the same conventional system with environmental and nutritional enrichment (CE, n=30) or in larger pens enriched with straw bedding (E, n=27). The enrichment of the CE group consisted of pieces of oak attached to a chain (three per pen) and straw pellets provided in the trough at a rate of 200 g/d from 3-30 days of gestation (DG) and 400 g/d from 31-104 DG. On DG 105, sows were transferred into farrowing pens and housed in identical individual stalls on a slatted floor. Cortisol concentration was measured in sow saliva during gestation, sow behavioural and investigative activities were recorded on DG 101 and piglet mortality was recorded. Cortisol concentration was greater (P<0.05) in C and CE than in E sows on DG 14 while it was intermediate in CE sows compared with C and E sows on DG 105 (before transfer to farrowing pens), and no longer differed among the 3 treatments on DG 107 (after the transfer). On DG 101, CE sows exhibited a lower proportion of stereotypies compared to C sows (22 vs 34%, P<0.05) but a greater proportion compared to E sows (7%, P<0.05). On this same day, CE sows had more investigative sequences than C sows (7.3±7.0 vs 1.7±1.8, P<0.01) but less than E sows (20.3±13.8; P<0.01). Rate of early mortality (i.e. piglets dead at birth + piglets that died within 12 h of birth) was lower in groups CE and E (6.6 and 6.3%, respectively) than in group C (11.1%, P<0.05), but overall mortality (stillbirth + preweaning death) did not differ significantly among the 3 groups (23.2, 19.1 and 19.3% in groups C, CE, and E, respectively, P=0.35). Enriching the sow environment and diet during gestation therefore improved sow welfare and reduced piglet mortality at and soon after birth. Research was funded by the EU FP7 Prohealth project (no. 613574)

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International audienc

Improving maternal welfare during gestation has positive outcomes on neonatal survival and modulates offspring immune response in pigs

International audienceImproving the housing of pregnant sows by giving them more space and access to deep straw had positive effects on their welfare, influenced their maternal behavior and improved the survival of their offspring. The present study aimed at determining whether these effects were actually due to environmental enrichment and whether the provision of straw pellets and wood can partly mimic the effects of straw bedding during gestation. Three graded levels of enrichment were used, that were, collective conventional pens on slatted floor (C, n = 26), the same pens with manipulable wood materials and distribution of straw pellets after the meals (CE, n = 30), and larger pens on deep straw litter (E, n = 27). Sows were then housed in identical farrowing crates from 105 days of gestation until weaning. Decreased stereotypies, blood neutrophils, and salivary cortisol, and increased behavioral investigation indicated that health and welfare of sows during gestation were improved in the E environment compared with the C environment. The CE sows responded as C or E sows depending on the trait. Piglet mortality rate in the first 12 h after birth was lower in E and CE litters than in C litters, but enrichment level during gestation had only small effects on lactating sow behavior and milk composition postpartum. On days 2 and 3 of lactation, E sows interrupted less often their nursing sequences than C and CE sows. On day 2, milk from both E and CE sows contained more minerals than that from C sows. In one-day-old piglets, the expression levels of genes encoding toll-like receptors (TLR2, TLR4) and cytokines (interleukin-1,-6 and-10) in whole blood after 20-h culture, were greater in E piglets than in CE or C piglets. In conclusion, housing sows in an enriched environment during gestation improved early neonatal survival, probably via moderate and cumulative positive effects on sow behavior, milk composition, and offspring innate immune response. The gradation in the effects observed in C, CE and E housing environment reinforced the hypothesis of a causal relationship between maternal environmental enrichment, sow welfare and postnatal piglet traits

Effect of environmental enrichment with wood materials and straw pellets on the metabolic status of sows during gestation

Environmental enrichment is a recognized strategy to improve sow welfare. Providing manipulable wood materials and straw pellets to sows during gestation might participate in satisfying their investigative behavior. Sows may also get a benefit from chewing and eating fibers, which can decrease their hunger. Such strategy, however, should not adversely affect metabolic status of sows and newborn piglets. In this study, gestating sows were group-housed in a conventional system on slatted floor (C, n = 26) or in the same system enriched with pieces of oak attached to a chain and straw pellets (CE, n = 30). Straw pellets were provided in the trough at a rate of 200 g/d from 3 to 30 days of gestation (DG) and 400 g/d from 31 to 104 DG. On DG105, sows were transferred into farrowing pens and housed in identical individual stalls on slatted floor. Sow body weight and backfat thickness were recorded before insemination, on DG105 and at weaning. Plasma concentrations of metabolites and insulin were measured in sows on DG73 and DG102. Blood was also collected from a subset of piglets at birth (n = 6 per litter in 5 C and 8 CE litters) to determine their metabolic and oxidative status. Sow body weight, backfat thickness, and estimated body lipid and protein masses did not differ between treatments during gestation and lactation. Maternal plasma concentrations of glucose, lactate, NEFA, beta‑hydroxy‑butyrate and insulin did not differ between groups (P > 0.10). However, CE sows had lower circulating concentrations of urea (P 0.10) piglet birth weight or plasma concentrations of glucose, fructose, lactate and albumin, antioxidant potential and the oxidative stress index in newborns. On the day after farrowing, the milk produced by CE sows contained more minerals (P < 0.01) than the milk of C sows but similar contents of protein, fat, lactose, energy and IgA. The proportion of piglets that died at birth and within 12 h of birth was lower in CE than in C litters (P < 0.05), but overall mortality (stillbirth + preweaning death) did not differ between the two groups. To conclude, providing manipulable materials and straw pellets to sows during gestation had little impact on sow metabolic status but improved early neonatal survival