Improved health, welfare and viability in young pigs: breeding for improved piglet survival

This factsheet evaluates the selection of sows with high potential for piglet survival to reduce piglet mortality and health problems. Additionally, it presents the results of the Core Organic Cofund project POWER on breeding’s relevance for animal welfare and its environmental impact

The early-life environment of a pig shapes the phenotypes of its social partners in adulthood

Social interactions among individuals are abundant, both in natural and domestic populations, and may affect phenotypes of individuals. Recent research has demonstrated that the social effect of an individual on the phenotype of its social partners may have a genetic component, known as an indirect genetic effect (IGE). Little is known, however, of nongenetic factors underlying such social effects. Early-life environments often have large effects on phenotypes of the individuals themselves later in life. Offspring development in many mammalian species, for example, depends on interactions with the mother and siblings. In domestic pigs, individuals sharing the same juvenile environment develop similar body weight later in life. We, therefore, hypothesized that offspring originating from the same early-life environment also develop common social skills that generate early-life social effects (ELSEs) that affect the phenotypes of their social partners later in life. We, therefore, quantified IGEs and ELSEs on growth in domestic pigs. Results show that individuals from the same early-life environment express similar social effects on the growth of their social partners, and that such ELSEs shape the growth rate of social partners more than IGEs. Thus, the social skills that individuals develop in early life have a long-lasting impact on the phenotypes of social partners. Early-life and genetic social effects were independent of the corresponding direct effects of offspring on their own growth, indicating that individuals may enhance the growth of their social partners without a personal cost. Our findings also illustrate how research devoted to quantifying IGEs may miss nongenetic and potentially confounded social mechanisms which may bias the estimates of IGEs

Late Fetal Blood Transcriptomic Approach To Get Insight Into Biology Related To Birth Survival

In recent decades, improvement of prolificacy and body composition has been accompanied by a substantial increase in the mortality of piglets before weaning. The most critical period is the perinatal period, mostly during the first 24-48 hours following birth. The maturity of piglets, defined as the state of full development for survival at birth, is an important determinant of early mortality. The objective of our project is to take advantage of current knowledge about two pig breeds, Large White (LW) pigs selected for prolificacy and body composition and Meishan (MS) pigs being more robust. Maturity of several tissues and metabolite profiles of various fluids are analyzed on the fetuses (LW, MS and reciprocal F1) at day 90 or 110 of gestation (birth at day 114). Here we presented the transcriptomic analysis done on total blood samples (N=63). We did two different statistical analyses, a supervised one to reveal differential pathways for the interaction between gestational stages and genotypes and an unsupervised analysis (hclust and differential analyses) to identify potential predictors of a lesser maturity at birth. All p-values were adjusted with a Bonferroni correction < 1%. The 265 genes differential for the interaction (Bonferroni 1%) in blood samples revealed many genes for mitochondrial ATP synthesis, transcriptional regulation, and response to hypoxia (overexpressed in LW at day 110 of gestation)

Comparing the intestinal transcriptome of Meishan and Large White piglets during late fetal development reveals genes involved in glucose and lipid metabolism and immunity as valuable clues of intestinal maturity

Background: Maturity of intestinal functions is critical for neonatal health and survival, but comprehensive description of mechanisms underlying intestinal maturation that occur during late gestation still remain poorly characterized. The aim of this study was to investigate biological processes specifically involved in intestinal maturation by comparing fetal jejunal transcriptomes of two representative porcine breeds (Large White, LW; Meishan, MS) with contrasting neonatal vitality and maturity, at two key time points during late gestation (gestational days 90 and 110). MS and LW sows inseminated with mixed semen (from breed LW and MS) gave birth to both purebred and crossbred fetuses. We hypothesized that part of the differences in neonatal maturity between the two breeds results from distinct developmental profiles of the fetal intestine during late gestation. Reciprocal crossed fetuses were used to analyze the effect of parental genome. Transcriptomic data and 23 phenotypic variables known to be associated with maturity trait were integrated using multivariate analysis with expectation of identifying relevant genes-phenotypic variable relationships involved in intestinal maturation. Results: A moderate maternal genotype effect, but no paternal genotype effect, was observed on offspring intestinal maturation. Four hundred and four differentially expressed probes, corresponding to 274 differentially expressed genes (DEGs), more specifically involved in the maturation process were further studied. In day 110-MS fetuses, Ingenuity® functional enrichment analysis revealed that 46% of DEGs were involved in glucose and lipid metabolism, cell proliferation, vasculogenesis and hormone synthesis compared to day 90-MS fetuses. Expression of genes involved in immune pathways including phagocytosis, inflammation and defense processes was changed in day 110-LW compared to day 90-LW fetuses (corresponding to 13% of DEGs). The transcriptional regulator PPARGC1A was predicted to be an important regulator of differentially expressed genes in MS. Fetal blood fructose level, intestinal lactase activity and villous height were the best predicted phenotypic variables with probes mostly involved in lipid metabolism, carbohydrate metabolism and cellular movement biological pathways. [b]Conclusions[/b]: Collectively, our findings indicate that the neonatal maturity of pig intestine may rely on functional development of glucose and lipid metabolisms, immune phagocyte differentiation and inflammatory pathways. This process may partially be governed by PPARGC1A

Capacité d'adaptation des truies et amélioration de la survie des porcelets

Capacité d'adaptation des truies et amélioration de la survie des porcelets. Diaporama de la présentation

Aspects génétiques de la mortalité des porcelets à la naissance et en allaitement précoce (relations avec les aptitudes maternelles des truies et la vitalité des porecelets)

PARIS-AgroParisTech Centre Paris (751052302) / SudocSudocFranceF

Analyse du déterminisme génétique de la caudophagie chez des femelles de la lignée Tai Zumu en fin d'engraissement

Cette étude porte sur la quantification des bases génétiques de la caudophagie chez des femelles Tai Zumu. Le phénotype mesuré est la présence de morsure(s) à la queue en fin d’engraissement, traduisant le fait que l’animal n’a pas su se défendre contre l’attaque de ses congénères. Les objectifs sont de 1/ comparer les performances de croissance et d’adiposité au contrôle à 100kg entre femelles indemnes et femelles mordues à la queue, 2/ quantifier la contribution d’effets génétiques sociaux, qui sont liés aux génotypes des partenaires de groupe, à la variation phénotypique du caractère ‘mordu’, et enfin 3/ estimer les effets de l’environnement sur l’expression génétique de ce caractère sous forme d’interactions génétique-environnement (GxE). La présence de morsure(s) a été enregistrée sur 33266 cochettes dans les trois élevages de sélection de la lignée. La prévalence variait entre 2,8% et 10,8% selon l’élevage. Ceux-ci diffèrent par les caractéristiques des groupes (ex. taille, nombre de mélanges) et le mode d’alimentation en engraissement. Les modèles d’analyse tenaient compte d’un effet génétique direct seul ou avec un effet génétique social. Les modèles ont été appliqués à la population globale des trois élevages et à chaque élevage séparément. Les effets génétiques sociaux contribuent à plus de 80% de la variance héritable. Leur prise en compte permet d’expliquer 40 à 80% de la variation phénotypique contre seulement 6 à 8% avec un modèle direct. Les différences entre élevages de classement des verrats connecteurs selon leurs valeurs génétiques, indiquent l’existence de fortes GxE puisque leurs corrélations de rang sont non différentes de 0. Bien que la part de variance génétique directe du caractère soit très faible, une sélection contre la caudophagie est possible. Inclure des effets génétiques sociaux permet de mieux quantifier la variation héritable et leur prise en compte dans les schémas augmenterait la réponse à la sélection contre ce comportement déviant.This study focusses on quantification of the genetic basis of tail-biting in Tai Zumu females. The phenotype under measure was the presence of tail bite(s) at the end of the fattening period, reflecting that the animal was unable to defend itself from groupmates’ attacks. The objectives were to (1) compare the growth and leanness performance at the monitoring at 100 kg between non-bitten females and bitten females; (2) quantify the contribution of social genetic effects, which depend on the genotypes of groupmates, to the phenotypic variation of the trait ‘bitten’; and (3) estimate the effect of the environment on the genetic expression of this trait as interactions between genetics and environment (GxE). The presence of tail bite(s) was recorded on 33,266 gilts from three nucleus herds. The prevalence of tail bites varied from 2.8% to 10.8% among herds that differed according to the groups’ characteristics (e.g., size, number of mixings) and feeding system during fattening. The models for analyses considered single direct genetic effects or also social genetic effects. Models were applied to the entire population including the three nucleus herds and to each herd taken separately. Social genetic effects contributed to more than 80% of total heritable variance, which equalled 40-80% of phenotypic variation, whereas only 6-8% was explained with a direct model. Differences in the ranking of connecting sires between herds according to their breeding values yielded rank correlations not different from zero, indicating strong GxE. Selection against tailbiting is possible even though the direct genetic contribution for this trait is low. Considering social genetic effects improves quantification of heritable variation, and accounting for them in breeding schemes would increase response to selection against this deviant behaviour

Genetics of tail-biting receipt in gilts from the Tai Zumu line

Tail-biting (TB) receipt was recorded at the end of the fattening period on 33,266 gilts of the Tai Zumu population, that were raised in groups of 6 to 20 females. This study aimed at quantifying the contribution of social genetic effects to TB receipt, and at assessing the importance of the environment on the genetic expression of this behaviour (GxE). Models for TB receipt included the fixed effects of number of group mates, (herd)-year-month, and the random effects of group, litter, and direct and social additive genetic effects. The model was applied to the complete gilt population and separately to 2 sub-populations, corresponding to 2 of the 3 nucleus herds raising that line, where TB receipt frequency differed and was high enough (>5%). TB receipt was analysed as a linear trait, following a normal distribution with the restricted likelihood methodology applied to an animal model. Social genetic effects contributed 81% to 93% of total heritable variance, which equalled 40 to 80% of phenotypic variation. The variance components varied between herds. The analysis of sire by environment interactions indicated re-ranking of sires between the 2 nucleus herds, according to both their direct and total breeding values

Mise au point de méthodes et d’outils spécifiques pour répondre à des questions de recherche autour du comportement animal

Des outils électroniques ont été développés/adaptés et rendus opérationnels pour étudier de façon automatisée le comportement des animaux en Unités ou Installations Expérimentales. Leur validation repose sur la confrontation des résultats fournis par les outils à des analyses du comportement observé de visu ou analysé à partir d’enregistrements vidéo sur des truies, vaches, chèvres, canards et oies. Ces mises au point facilitent grandement l’analyse du comportement (CPT) animal et octroient un gain de temps important aux chercheurs qui traitent ces thématiques dans l’acquisition des données, tout en leur permettant d’accéder à des phénotypes plus fins et parfois originaux

Analyse génétique de la productivité numérique et pondérale et de la durée de mise bas de truies Large White et Landrace Français

National audienceGenetic parameters were estimated for numbers of piglets born in total (TNB), born alive (NBA), stillborn (NSB) and weaned (NW) per litter, birth to weaning survival rate (SR), farrowing duration (FD), litter weight and within-litter standard deviation of individual piglet weight (SDPW) at birth. Data were collected on 29,153 and 16,354 litters in Large White (LW) and French Landrace (LR), respectively, between 2002 and 2005. The analyses were carried out using restricted maximum likelihood methodology. All traits were analysed using a mixed linear animal model including herd, year x month and parity as fixed effects, the additive genetic value and the permanent environment of each sow, as well as sire of litter, as random effects. Low heritability estimates were obtained for litter size (0.10 to 0.13) and mortality traits (0.06 to 0.11). NSB had unfavourable genetic correlations with TNB (0.49 and 0.56 in LW and LR, respectively), but low genetic correlations with NBA (0.05 and 0.18). Both TNB and NBA showed a genetic antagonism with SR (–0.24±0.09 to –0.32±0.07). The number of stillborn was positively correlated with FD at the genetic level (0.64±0.08 and 0.41±0.09 in LW and LR, respectively). Litter weight was positively correlated with litter size and had low (LR) to moderate (LW) genetic correlations with SR. SDPW was genetically associated with lower SR (-0.21±0.18 to –0.28±0.33 in LW and LR, respectively)