Perception de l'humain et processus émotionnels et cognitifs chez le porcelet : impact de l'expérience avec l'humain

L’humain, faisant partie de l’environnement des animaux domestiques, peut avoir un impact profond sur leur bien-être. Au cours de cette thèse, le regard a été porté sur la période post-sevrage chez le porc, une période peu étudiée dans le contexte de relation homme-animal qui pourtant est associée au développement des comportements sociaux. La première partie était consacrée à la compréhension de processus impliqués dans la perception de l’humain par le porcelet sevré, à savoir la mémoire, la reconnaissance et la généralisation. Les résultats ont montré que les porcelets peuvent former une mémoire de l’individu humain qui persiste au moins 5 semaines. Ainsi, les porcelets adaptent leurs comportements selon la nature des contacts (brusques ou doux) reçus par l’humain. L’ajout de récompenses alimentaires ou de stress physiques n’amplifie pas les réponses comportementales. L’humain inconnu n’est pas perçu positivement. De plus, la familiarisation à la présence passive de l’humain n’élimine pas la peur face à l’approche de l’humain, suggérant que les porcelets ont une mémoire spécifique au contexte. Il a été montré que les porcelets sont capables de discriminer et reconnaître les humains familiers sur la base de l’expérience, bien que leurs réactions dépendent de nombreux facteurs, incluant la constance de l’expérience et le contexte de test. En outre, ils sont capables de généraliser leurs réactions face à des inconnus et de former une mémoire globale de l’être humain. Dans une seconde partie, l’impact de l’expérience avec l’humain sur l’état émotionnel et les capacités cognitives du porcelet sevré a été investigué. Les résultats montrent que la manière dont l’humain se comporte avec les porcelets a un réel impact sur l’état émotionnel des jeunes animaux. Les porcelets recevant des contacts positifs par l’humain développent un bon état émotionnel et sont plus optimistes. En outre, la peur de l’humain est corrélée avec la motivation à explorer, un trait de tempérament aidant les animaux dans une tâche d’apprentissage. L’ensemble de ce travail montre que la nature des contacts donnés par l’humain joue un rôle dans la perception de l’homme, influence l’état émotionnel des porcelets et est aussi liée à la motivation du porcelet à apprendre et s’adapter à son environnement. Mots-clefs : porcelet sevré, relation homme-animal, bien-être / mal-être, perception de l’humain, reconnaissance/généralisation, état émotionnel, biais cognitif, apprentissage.Humans are part of the environment of domestic animals and their impact on animal welfare is largely underestimated. This thesis focused on the human-animal relationship during the post-weaning period in pigs. This period has not been much studied in a context of human-animal relationship, although it is known to be associated with the development of social abilities. The first part of this thesis aimed at understanding some processes involved in the development of the perception of humans by weaned piglets, namely memory, recognition and generalisation. Results showed that weaned piglets are able to form a memory of a familiar human which persists at least 5 weeks. Moreover, piglets adapt their behaviour according to the movements (rough or gentle) of humans towards them. However, the addition of food rewards or physical stress does not amplify their behavioural responses. An unfamiliar handler is not perceived positively. In addition, familiarisation to a passive human is not sufficient to remove the fear of an approaching human, suggesting that piglets form a context-specific memory. Thereafter, it has been shown that piglets can discriminate and recognise familiar humans based on experience, although their reactions depend on numerous factors, including the consistency of the experience and the context of testing. It does not preclude that piglets are able to generalise their behavioural responses to unfamiliar humans and to form a general memory of humans. The second part of the thesis aimed at investigating the impact of the experience with humans on emotional states and cognitive abilities of weaned piglets. It has been demonstrated that the way humans behave with piglets modulates their emotional states. Piglets receiving positive interactions with humans develop a positive emotional state and are more optimistic. Fear of humans appears to be correlated with motivation to explore, a temperament trait helping animals in a learning task. Overall, it has been demonstrated that the nature of the contact given by humans plays a major role in the development of the perception of humans, but also influences emotional states and is linked with motivation of this young domestic animal to learn and adapt to its environment. Key words: weaned piglet, human-animal relationship, welfare, perception of humans, recognition/generalisation, emotional state, cognitive bias, learning

The role of genetic selection on agonistic behavior and welfare of gestating sows housed in large semi-static groups

Confinement of gestating sows is becoming banished in favor of group-housing in countries worldwide, forcing breeding companies to develop genetic lines adapted for social living. This study aimed at assessing the influence of two genetic lines selected for high performance (HP1, HP2, derived from Landrace × Yorkshire) on welfare and reproductive performance of sows housed in large semi-static groups (20 groups of 46–91 animals) across several parities. To address this, agonistic behaviors were recorded on d0, d2, d27, and d29 post-mixing while body lesions were scored on d1, d26, and d84. Sows’ individual and reproductive performances were also recorded. HP2 sows were more aggressive than HP1 sows since they fought (p = 0.028) and bullied (p = 0.0009) pen-mates more frequently on d0–d2. HP2 sows had more total body lesions throughout gestation than HP1 sows at higher parities (p < 0.0001). Regarding reproductive performance, HP2 sows lost less piglets (p < 0.0001) and tended to wean more piglets (p = 0.067) than HP1 sows. In conclusion, while HP2 sows were the most aggressive, HP1 sows had piglets with lower survivability, which raises ethical issues in both cases and points to the need of considering social aspects when developing genetic lines for group-housing

Perception de l’humain et processus émotionnels et cognitifs chez le porcelet : Impact de l’expérience avec l’humain

Humans are part of the environment of domestic animals and their impact on animal welfare is largely underestimated. This thesis focused on the human-animal relationship during the post-weaning period in pigs. This period has not been much studied in a context of human-animal relationship, although it is known to be associated with the development of social abilities. The first part of this thesis aimed at understanding some processes involved in the development of the perception of humans by weaned piglets, namely memory, recognition and generalisation. Results showed that weaned piglets are able to form a memory of a familiar human which persists at least 5 weeks. Moreover, piglets adapt their behaviour according to the movements (rough or gentle) of humans towards them. However, the addition of food rewards or physical stress does not amplify their behavioural responses. An unfamiliar handler is not perceived positively. In addition, familiarisation to a passive human is not sufficient to remove the fear of an approaching human, suggesting that piglets form a context-specific memory. Thereafter, it has been shown that piglets can discriminate and recognise familiar humans based on experience, although their reactions depend on numerous factors, including the consistency of the experience and the context of testing. It does not preclude that piglets are able to generalise their behavioural responses to unfamiliar humans and to form a general memory of humans. The second part of the thesis aimed at investigating the impact of the experience with humans on emotional states and cognitive abilities of weaned piglets. It has been demonstrated that the way humans behave with piglets modulates their emotional states. Piglets receiving positive interactions with humans develop a positive emotional state and are more optimistic. Fear of humans appears to be correlated with motivation to explore, a temperament trait helping animals in a learning task. Overall, it has been demonstrated that the nature of the contact given by humans plays a major role in the development of the perception of humans, but also influences emotional states and is linked with motivation of this young domestic animal to learn and adapt to its environment.L’humain, faisant partie de l’environnement des animaux domestiques, peut avoir un impact profond sur leur bien-être. Au cours de cette thèse, le regard a été porté sur la période post-sevrage chez le porc, une période peu étudiée dans le contexte de relation homme-animal qui pourtant est associée au développement des comportements sociaux. La première partie était consacrée à la compréhension de processus impliqués dans la perception de l’humain par le porcelet sevré, à savoir la mémoire, la reconnaissance et la généralisation. Les résultats ont montré que les porcelets peuvent former une mémoire de l’individu humain qui persiste au moins 5 semaines. Ainsi, les porcelets adaptent leurs comportements selon la nature des contacts (brusques ou doux) reçus par l’humain. L’ajout de récompenses alimentaires ou de stress physiques n’amplifie pas les réponses comportementales. L’humain inconnu n’est pas perçu positivement. De plus, la familiarisation à la présence passive de l’humain n’élimine pas la peur face à l’approche de l’humain, suggérant que les porcelets ont une mémoire spécifique au contexte. Il a été montré que les porcelets sont capables de discriminer et reconnaître les humains familiers sur la base de l’expérience, bien que leurs réactions dépendent de nombreux facteurs, incluant la constance de l’expérience et le contexte de test. En outre, ils sont capables de généraliser leurs réactions face à des inconnus et de former une mémoire globale de l’être humain. Dans une seconde partie, l’impact de l’expérience avec l’humain sur l’état émotionnel et les capacités cognitives du porcelet sevré a été investigué. Les résultats montrent que la manière dont l’humain se comporte avec les porcelets a un réel impact sur l’état émotionnel des jeunes animaux. Les porcelets recevant des contacts positifs par l’humain développent un bon état émotionnel et sont plus optimistes. En outre, la peur de l’humain est corrélée avec la motivation à explorer, un trait de tempérament aidant les animaux dans une tâche d’apprentissage. L’ensemble de ce travail montre que la nature des contacts donnés par l’humain joue un rôle dans la perception de l’homme, influence l’état émotionnel des porcelets et est aussi liée à la motivation du porcelet à apprendre et s’adapter à son environnement

The Role of Genetic Selection on Agonistic Behavior and Welfare of Gestating Sows Housed in Large Semi-Static Groups

Confinement of gestating sows is becoming banished in favor of group-housing in countries worldwide, forcing breeding companies to develop genetic lines adapted for social living. This study aimed at assessing the influence of two genetic lines selected for high performance (HP1, HP2, derived from Landrace &times; Yorkshire) on welfare and reproductive performance of sows housed in large semi-static groups (20 groups of 46&ndash;91 animals) across several parities. To address this, agonistic behaviors were recorded on d0, d2, d27, and d29 post-mixing while body lesions were scored on d1, d26, and d84. Sows&rsquo; individual and reproductive performances were also recorded. HP2 sows were more aggressive than HP1 sows since they fought (p = 0.028) and bullied (p = 0.0009) pen-mates more frequently on d0&ndash;d2. HP2 sows had more total body lesions throughout gestation than HP1 sows at higher parities (p &lt; 0.0001). Regarding reproductive performance, HP2 sows lost less piglets (p &lt; 0.0001) and tended to wean more piglets (p = 0.067) than HP1 sows. In conclusion, while HP2 sows were the most aggressive, HP1 sows had piglets with lower survivability, which raises ethical issues in both cases and points to the need of considering social aspects when developing genetic lines for group-housing

Social status and previous experience in the group as predictors of welfare of sows housed in large semi-static groups.

Mixing gestating sows implies hierarchy formation and has detrimental consequences on welfare. The effects of social stress on the most vulnerable individuals may be underestimated and it is therefore important to evaluate welfare between individuals within groups. This study aimed at investigating the impact of social status and previous experience in the group on well-being of sows housed in large semi-static groups. We assessed aggression (d0 (mixing), d2, d27, d29), body lesions (d1, d26, d84) and feeding order on 20 groups of 46-91 animals. Social status was based on the proportion of fights won during a 6-hr observation period between d0 and d2. Dominants (29%) were those who won more fights than they lost, Subdominants (25%) won fewer fights than they lost, Losers (23%) never won any fight in which they were involved while Avoiders (23%) were never involved in fights. Resident sows (70%) were already present in the group in the previous gestation while New sows (30%) were newly introduced at mixing. Subdominants and Dominants were highly involved in fights around mixing but this was more detrimental for Subdominants than Dominants, Losers and Avoiders since they had the highest body lesion scores at mixing. Avoiders received less non-reciprocal agonistic acts than Losers on d2 (P = 0.0001) and had the lowest body lesion scores after mixing. However, Avoiders and Losers were more at risk in the long-term since they had the highest body lesions scores at d26 and d84. They were followed by Subdominants and then Dominants. New sows fought more (P<0.0001), tended to be involved in longer fights (P = 0.075) around mixing and had more body lesions throughout gestation than Resident sows. Feeding order from one-month post-mixing was influenced both by the previous experience in the group and social status (P<0.0001). New sows, especially with a low social status, are more vulnerable throughout gestation and could serve as indicators of non-optimal conditions

The Way Humans Behave Modulates the Emotional State of Piglets.

The emotional state can influence decision-making under ambiguity. Cognitive bias tests (CBT) proved to be a promising indicator of the affective valence of animals in a context of farm animal welfare. Although it is well-known that humans can influence the intensity of fear and reactions of animals, research on cognitive bias often focusses on housing and management conditions and neglects the role of humans on emotional states of animals. The present study aimed at investigating whether humans can modulate the emotional state of weaned piglets. Fifty-four piglets received a chronic experience with humans: gentle (GEN), rough (ROU) or minimal contact (MIN). Simultaneously, they were individually trained on a go/no-go task to discriminate a positive auditory cue, associated with food reward in a trough, from a negative one, associated with punishments (e.g. water spray). Independently of the treatment (P = 0.82), 59% of piglets completed the training. Successfully trained piglets were then subjected to CBT, including ambiguous cues in presence or absence of a human observer. As hypothesized, GEN piglets showed a positive judgement bias, as shown by their higher percentage of go responses following an ambiguous cue compared to ROU (P = 0.03) and MIN (P = 0.02) piglets, whereas ROU and MIN piglets did not differ (P > 0.10). The presence of an observer during CBT did not modulate the percentage of go responses following an ambiguous cue (P > 0.10). However, regardless of the treatment, piglets spent less time in contact with the trough following positive cues during CBT in which the observer was present than absent (P < 0.0001). This study originally demonstrates that the nature of a chronic experience with humans can induce a judgement bias indicating that the emotional state of farm animals such as piglets can be affected by the way humans interact with them

Differential effects of increased corticosterone on behavior at the nest and reproductive output of chick-rearing Adélie penguins

International audienceGlucocorticoid hormones (GCs) are important mediators of physiological and behavioral responses to stress. While many studies have evaluated the environmental, behavioral, or physiological correlates of GCs and their effects on reproductive performances, further work is needed to clarify the relationship between GCs and fitness. Assessing the effects of increased GC levels on specific behaviors of breeding animals should improve our understanding of how GCs affect parental care. In this experimental study, we measured the effects of an experimental increase in corticosterone (CORT, the main avian GC) levels on the behavior of free-living male Adélie penguins (Pygoscelis adeliae) within the colony, their reproductive output, and the indirect consequences of both on the behavior of their partners. We show that increased CORT levels in males decreased their foraging time at sea while increased their attendance at the nest, although their attentiveness toward the nest itself decreased. In addition, treated males spent more time on comfort behaviors (e.g., preening), vocalizing, and engaging in positive social interactions relative to controls. Treatment further affected the behavior of their partners, but not chick begging and feeding rates. Penguins with increased CORT levels also exhibited decreased reproductive output. Previous studies of Adélie penguins in different life history stages and environmental conditions suggest that the consequences of CORT treatment on reproductive performance are context-dependent. In addition to the potential delay in the effects of increased CORT levels on reproduction, this context dependence should be taken into account when studying the behavior of free-living animals in relation to stress-inducing situations

Mutual interactions between cognition and welfare: the horse as an animal model

International audienceResearch in cognitive psychology has repeatedly shown how much cognition and emotions are mutually related to one another. Psychological disorders are associated with cognitive (attention, memory and judgment) biases and chronic pain may affect attention, learning or memory. Laboratory studies have provided useful insights about the processes involved but observations about spontaneous animal models, living in different stress/welfare conditions may help understand further how cognition and welfare are interrelated in the « real world ». Domestic horses constitute such a model as they live in a variety of conditions that impact differently their welfare state. In the present review, we try and provide an overview of the scientific literature on cognition and welfare of domestic horses and their interrelationship. We address how emotions and welfare may affect cognitive processes in horses and impact the way they perceive their environment (including work). We propose new methods for assessing the relationship between welfare and cognition and open up the discussion on the evolution of the brain and the part domestication may have played

Évaluation d’enrichissements pour améliorer le bien-être des poulets de chair

International audienceIn response to societal expectations, poultry industry intends to propose ways to improve poultry welfare in indoor systems while controlling the economic costs. The implementation of physical enrichment in the living environment seems particularly beneficial for the poultry welfare. Five farms in France producing broilers from Ross308 or JA987 strains were monitored between March and June 2021. The goal was to evaluate the strengths and weaknesses of enrichments from the animal and farmer’s point of views. The enrichments were designed to meet different behavioral needs such as exploring (pecking blocks, strings, chains, straw bales, balloons, bag of pellets), roosting and resting (platform perches, linear perches, straw bales and vertical panels) and dust bathing (boxes). First, behavioral observations of the animals (1-min scan-sampling for 5-min and 5-min live observation using continuous sampling, twice per day) were performed and analyzed using Kruskal-Wallis and Mann-Whitney tests. Then, semi-structured interviews with farmers were conducted and analyzed by thematic descriptive analysis. Enrichments had an impact on the broilers' behaviour: more animals were seen exploring when there was an enrichment for pecking than when there was nothing (10% of animals/scan against 2%, p<0.05). They seemed less stable on thin perches than on platform perches (-20% of animals/scan grooming on thin perches, p<0.05) and preferred to perch on large surfaces (60% of animals/scan against 10% if thin perches, p<0.001). Multi-criteria analyses based on the interviews and behavioral analysis allowed at identifying suitable enrichments such as straw bales, which were favorable both for broilers due to their dual function (perching and pecking) and farmers (repacking litter). This study shows that some basic needs of broilers are satisfied by the presence of enrichments. It is important to provide different types of enrichments so that broilers can exhibit their full behavioral repertoire and thus have an improved welfare.Face aux attentes sociétales, la filière avicole souhaite proposer des axes d’amélioration du bien-être des volailles en système claustré tout en maîtrisant les surcoûts économiques. La mise en place d’enrichissements physiques du milieu de vie semble bénéfique au bien-être des volailles. Cinq élevages du Grand-Ouest produisant des poulets de chair Ross308 ou JA987 ont été suivis entre mars et juin 2021 afin d’évaluer les forces et faiblesses d’enrichissements du point de vue de l’animal et de l’éleveur. Les enrichissements visaient à répondre à différents besoins comportementaux tels qu’explorer (blocs à picorer, ficelles, chaînettes, ballots de paille, ballons, sacs de granulés), se percher et se reposer (perchoirs plateformes, linéaires, ballots de paille, panneaux verticaux) et réaliser des bains de poussière (bac). D’une part, des observations comportementales des animaux (scan sampling toutes les 1-mn sur 5-mns et continuous sampling sur 5-mns, deux fois par jour) ont été effectuées et analysées par des tests de Kruskal-Wallis et Mann-Whitney. D’autre part, des entretiens semi-directifs avec les éleveurs ont été menés, analysés via une analyse descriptive thématique. Les enrichissements ont eu un impact sur les comportements des poulets : davantage d’oiseaux exploraient lorsqu’il y avait la présence d’un enrichissement à piquer que lorsqu’il n’y en avait pas (10% d’oiseaux/scan contre 2%, p<0,05). Les panneaux verticaux, plateformes, perchoirs en A et ballots de paille ont particulièrement été plébiscités par les poulets pour se reposer. Toutefois, moins de toilettage ont été constatés sur les perchoirs fins (-20% d’oiseaux/scan se toilettent sur les perchoirs linéaires comparativement aux perchoirs plateformes, p<0,05). Les poulets semblaient préférer être plus au contact, notamment perchés, des perchoirs à surfaces larges (60% d’animaux au contact de l’enrichissement/scan contre 10% si perchoirs fins, p<0,001). Des analyses multicritères ont permis d’identifier des enrichissements à privilégier tels que les ballots de paille, bénéfiques pour les poulets grâce à leur double fonction (perchage et picorage) et les éleveurs (peu couteux, repaillage, pas de nettoyage). Cette étude montre que l’ajout d’enrichissements permettrait de mieux satisfaire, plus ou moins spécifiquement selon leur type, certains besoins essentiels du poulet. Il apparait important d’apporter différents types d’enrichissements pour que les poulets puissent exprimer la totalité de leur répertoire comportemental et ainsi améliorer leur bien-être