Classification of pig calls produced from birth to slaughter according to their emotional valence and context of production

Vocal expression of emotions has been observed across species and could provide a non-invasive and reliable means to assess animal emotions. We investigated if pig vocal indicators of emotions revealed in previous studies are valid across call types and contexts, and could potentially be used to develop an automated emotion monitoring tool. We performed an analysis of an extensive and unique dataset of low (LF) and high frequency (HF) calls emitted by pigs across numerous commercial contexts from birth to slaughter (7414 calls from 411 pigs). Our results revealed that the valence attributed to the contexts of production (positive versus negative) affected all investigated parameters in both LF and HF. Similarly, the context category affected all parameters. We then tested two different automated methods for call classification; a neural network revealed much higher classification accuracy compared to a permuted discriminant function analysis (pDFA), both for the valence (neural network: 91.5%; pDFA analysis weighted average across LF and HF (cross-classified): 61.7% with a chance level at 50.5%) and context (neural network: 81.5%; pDFA analysis weighted average across LF and HF (cross-classified): 19.4% with a chance level at 14.3%). These results suggest that an automated recognition system can be developed to monitor pig welfare on-farm.publishedVersio

Effets comparés du retrait d'un congénère ou d'un objet familier sur la réactivité émotionnelle des agneaux

National audienc

Conséquences d'un stress prénatal sur le développement neurobiologique de l'agneau nouveau-né

National audienc

Régulation des émotions chez l'animal d'élevage : focus sur les acteurs neurobiologiques

Dossier : Neurobiologie des fonctions et des comportementsThe interest for emotion in farm animals is motivated by the aim to improve welfare in livestock production. The study of emotions is based on the cognitive capacities of animals to perceive, evaluate and react to their environment. The perception capacity involves different senses, allows the animal to recognize its environment, and not necessarily induces emotion. Emotions are induced by specific situations as novelty, social separation or predator. Moreover, emotional reactions, evaluated by behavioural, endocrine and neurovegetative responses, are modulated by gender, physiological state or some hormones such as melatonin. The brain structures of the neuronal network of emotions are involved in perception, integrative levels and expression of emotional responses. In farm animals, the most studied brain structures are those of the olfactory system for perception, the frontal cortex and amygdala for integration of the environment, the paraventricular nucleus of the hypothalamus for endocrine responses. Other studies hypothesize the role of the brainstem nuclei in neurovegetative responses, and those of the periaqueductal grey for its putative role in behavioural responses and more generally in the coping strategy. In perspective, it is necessary to better understand the development of the neuronal network of emotions in farm animals, especially the effect of early experience, and the cognitive evaluation involved in emotion.La question des émotions des animaux d’élevage s’inscrit dans la volonté d’améliorer les conditions d’élevage en prenant en compte leur bien-être. La genèse des émotions repose sur la capacité cognitive des individus à percevoir, évaluer et réagir à leur environnement. La capacité de perception met en jeu différentes sensorialités et participe à la reconnaissance des éléments de l’environnement de l’animal sans nécessairement déclencher d’émotions. Les situations déclenchantes d’émotion les plus étudiées chez les animaux d’élevage sont la nouveauté, la séparation sociale ou la présence d’un être humain. De plus, les réactions émotionnelles, évaluées par les réponses comportementales, endocriniennes et neurovégétatives sont modulées par le genre, l’état physiologique ou certaines hormones comme la mélatonine. Les structures cérébrales du réseau neuronal des émotions sont impliquées dans la perception et le traitement des informations de l’environnement, et/ou dans l’expression des réponses émotionnelles. Chez les animaux d’élevage, les structures cérébrales les plus étudiées sont le système olfactif pour la perception, le cortex frontal et l’amygdale pour le traitement des informations, le noyau paraventriculaire de l’hypothalamus pour les réponses endocriniennes. D’autres travaux suggèrent le rôle potentiel de structures du tronc cérébral dans les réponses neurovégétatives et de la substance grise périaqueducale dans les réponses comportementales et plus largement dans les stratégies d’adaptation. En perspective, il est maintenant nécessaire d’étudier l’impact de l’expérience précoce sur le développement du réseau neuronal des émotions et de mieux comprendre la part de l’évaluation cognitive dans la genèse des émotions

Chronic stress induces pessimistic-like judgment and learning deficits in sheep

Concernant l'affiliation Inra "Physiologie de la reproduction et des comportements" : le codique 6175 indiqué sur la publication est erroné. Le bon codique est 0085.Chronic stress can be described as a long-term negative affective state induced by an accumulation of negative emotional experiences that alters an individual's interactions with the environment. In humans, chronic stress induces both persistent judgment biases and learning deficits. We investigated whether similar cognitive biases could occur in sheep. Twenty-four lambs were subjected to a chronic stress treatment for 9 weeks (exposure to various unpredictable, uncontrollable and aversive events regularly encountered in ordinary agricultural practices) and 24 other lambs were used as a control group. Before treatment all the lambs had been trained to approach or avoid a food bucket depending on its location. After treatment, the lambs were individually exposed to two tests: (i) a food bucket approach/avoidance test, by testing the response of lambs to ambiguous locations of the bucket, i.e. a judgment bias test, (ii) a learning test consisting of training on six consecutive days to distinguish between two visual stimuli differing in their color and shape (acquisition phase) and re-exposure to the test conditions 2 days after the end of the acquisition phase (recall phase). In the judgment bias test, treated lambs took longer to approach the ambiguous locations of the bucket. During the learning test, treated lambs had lower numbers of correct choices than control lambs in the acquisition and recall phase. Hence sheep experiencing repeated aversive events demonstrated pessimistic-like judgment biases and learning deficits. These may be useful measures to assess long-term emotional states in animals

Un stress chronique subi avant la puberté stimule la proceptivité et la réceptivité sexuelles des brebis

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Stress during pregnancy alters dendritic spine density and gene expression in the brain of new-born lambs

Remerciements :INRA, UE0332 BOURGES Domaine Expérimental Bourges-La SapinièreRodent studies show how prenatal stress (PS) can alter morphology in the cortico-limbic structures that support emotional and cognitive functions. PS-induced alteration is less well described in species with a gyrencephalic brain and complex earlier fetal development, and never in sheep at birth to rule out postnatal environment effects or influences of maternal behavior. This study aimed to assess the consequences of a mild chronic stress in pregnant ewes on the neurobiological development of their lambs at birth. During the last third of gestation, 7 ewes were exposed daily to various unpredictable and negative routine management-based challenges (stressed group), while 7 other ewes were housed without any additional perturbation (control group). For each group, a newborn from each litter was sacrificed at birth to collect its brain and analyze its expression levels of genes involved in neuronal dendritic morphology (Dlg4, Rac1, RhoA, Doc2b), synaptic transmission (Nr1, Grin2A, Grin2B) and glucocorticoid receptor (Nr3C1) in hippocampus (HPC), prefrontal cortex (PFC) and amygdala (AMYG). Results revealed that lambs from stressed dam (PS lambs) showed under-expression of Rac1 and Nr1 in PFC and overexpression of Dlg4 in AMYG compared to controls. To assess the morphological consequences of gene dysregulations, the dendritic morphology of pyramidal neurons was explored by Golgi–Cox staining in HPC and PFC. PS lambs had higher dendritic spine density in both structures and more stubby-type spines in the CA1 area of HPC than controls. This is the first demonstration in sheep that PS alters fetal brain, possibly reflecting functional changes in synaptic transmission to cope with adversity experienced in fetal life

Effects of a chronic stress treatment on vaccinal response in lambs

International audienceFarming systems can expose animals to chronic mild stress which is known to induce negative affective state. Affective state in animals, as in humans, can be assessed through behavioral cues. This study aimed to describe the effect of a chronic mild stress, known to induce a negative affective state, on sheep health through their response to vaccination. The study used 15 lambs subjected to a model of chronic mild stress for 15 weeks and 15 lambs reared under conventional farming as a control group. After 7 weeks of stressful treatment, the lambs were individually exposed to a judgment bias test to assess a putative stress-induced 'pessimism.' After 15 weeks of stressful treatment, antibody immune response was measured after an injection of a live vaccine challenge (Chlamydia abortus attenuated vaccine strain 1B). Stressed lambs displayed a pessimistic-like perception in the judgment bias test, revealing a negative affective state. Stressed and control animals showed different immunological reactions to vaccine challenge: stressed sheep had lower hemoglobin concentrations and higher platelet, granulocyte and acute-phase protein concentrations. Antibody response induced by the vaccine strain was not different between stressed and control sheep. Our results suggest that negative affective state induced by chronic stress treatment may induce a stronger inflammatory response to vaccine challenge in sheep. Improvement of animal health may be achieved through consideration of stressors that may affect the emotional and immunological state of sheep

Prenatal stress modifies the dendritic spine density in hippocampus and prefrontal cortex of lambs at birth whereas the genes expression in dendritic morphology and synaptic transmission is not altered

Prenatal stress modifies the dendritic spine density in hippocampus and prefrontal cortex of lambs at birth whereas the genes expression in dendritic morphology and synaptic transmission is not altered. 10. Forum of Neurosciences of the Federation of European Neuroscience Societ

Améliorer le bien-être des animaux d’élevage : est-ce toujours possible ?

Revue SésameChercheur.ses qui étudions le comportement des animaux d’élevage, nous avons proposé des changements de pratiques afin d‘améliorer le bien-être de ces animaux. Après toutes ces années où nous avons travaillé avec l’injonction d’améliorer le bien-être animal, nous faisons le bilan des retombées de nos travaux : certains systèmes n’ont pas été améliorés, et pour cause, ils ne sont pas améliorables