Animal board invited review: Improving animal health and welfare in the transition of livestock farming systems: Towards social acceptability and sustainability.

The need to integrate more clearly societal expectations on livestock farming has led the authors of this article to consider that livestock farming systems must be redesigned to position health and welfare at the heart of their objectives. This article proposes a vision of the advances in knowledge required at different scales to contribute to this transformation. After defining health and welfare of animals, the article emphasises the need to consider health in a broader perspective, to deepen the question of positive emotional experiences regarding welfare, and raises the question of how to assess these two elements on farms. The positive interactions between health and welfare are presented. Some possible tensions between them are also discussed, in particular when improving welfare by providing a more stimulating and richer environment such as access to outdoor increases the risk of infectious diseases. Jointly improving health and welfare of animals poses a number of questions at various scales, from the animal level to the production chain. At the animal level, the authors highlight the need to explore: the long-term links between better welfare and physiological balance, the role of microbiota, the psycho-neuro-endocrine mechanisms linking positive mental state and health, and the trade-off between the physiological functions of production, reproduction and immunity. At the farm level, in addition to studying the relationships at the group level between welfare, health and production, the paper supports the idea of co-constructing innovative systems with livestock farmers, as well as analysing the cost, acceptability and impact of improved systems on their working conditions and well-being. At the production chain or territory levels, various questions are raised. These include studying the best strategies to improve animal health and welfare while preserving economic viability, the labelling of products and the consumers' willingness to pay, the consequences of heterogeneity in animal traits on the processing of animal products, and the spatial distribution of livestock farming and the organisation of the production and value chain. At the level of the citizen and consumer, one of the challenges is to better inter-relate sanitary and health perspectives on the one hand, and welfare concerns on the other hand. There is also a need to improve citizens' knowledge on livestock farming, and to develop more intense and constructive exchanges between livestock farmers, the livestock industry and citizens. These difficult issues plead for interdisciplinary and transdisciplinary research involving various scientific disciplines and the different stakeholders, including public policy makers through participatory research.

Short- and mid-term effects on performance, health and qualitative behavioural assessment of Romane lambs in different milk feeding conditions.

The common practice of artificially rearing lambs from prolific meat breeds of sheep constitutes a welfare issue due to increased mortality rates and negative health issues. In this multidisciplinary study, we investigated the possible short- and mid-term advantages of artificially feeding fresh ewe's milk instead of commercial milk replacer on lambs' growth, health and welfare. Romane lambs were either separated from their mothers on D3 and fed with Lacaune ewes' milk (LAC, n = 13) or milk replacer (REP, n = 15), or they were reared by their mothers (MOT, n = 15). On D45, they were weaned, gathered in single-sex groups until the end of the study on D150. Lamb performance and biomarkers of overall health were assessed by measuring: growth, dirtiness of the perianal area, enteric pathogens in the faeces, total antioxidant status and redox status assessed by plasma reduced glutathione/oxidised glutathione ratio, and immune response after vaccination against chlamydiosis. As an exploratory approach, blood cell transcriptomic profiles were also investigated. Last, qualitative behaviour assessment (QBA) was performed as an integrated welfare criterion. Lacaune ewes' milk and REP never differed in their average daily gain but grew less than MOT lambs in the early suckling period and just after weaning. No effect was detected afterwards. On D30, LAC and REP lambs had lower total antioxidant and higher redox status than MOT lambs but did not differ among themselves. Lacaune ewes' milk and MOT had a cleaner perianal area than REP lambs on D21, while faecal pathogen infection did not vary between the treatment groups. After vaccination, LAC also had a stronger immune response on D90 compared to REP lambs. Transcriptome analysis performed on D150 showed differential gene expression, mainly in relation to inflammatory, immune and cell cycle response, between male lambs of the LAC group and those of the MOT and REP groups. Based on QBA, LAC lambs never differed from MOT lambs in their general activity and varied from REP only on D21; REP lambs were always more agitated than MOT lambs. In conclusion, artificial milk feeding impaired early growth rate, health and emotional state mainly during the milk feeding period and at weaning. Feeding artificially reared lambs with fresh ewe's milk partly mitigated some of the negative effects induced by milk replacer but without achieving the full benefit of being reared by the mother.

Piglets vocally express the anticipation of pseudo-social contexts in their grunts.

Emotions not only arise in reaction to an event but also while anticipating it, making this context a means of accessing the emotional value of events. Before now, anticipatory studies have rarely considered whether vocalisations carry information about emotional states. We studied both the grunts of piglets and their spatial behaviour as they anticipated two (pseudo)social events known to elicit positive emotions of different intensity: arrival of familiar conspecifics and arrival of a familiar human. Piglets spatially anticipated both pseudo-social contexts, and the spectro temporal features of grunts differed according to the emotional context. Piglets produced low-frequency grunts at a higher rate when anticipating conspecifics compared to anticipating a human. Spectral noise increased when piglets expected conspecifics, whereas the duration and frequency range increased when expecting a human. When the arrival of conspecifics was delayed, the grunt duration increased, whereas when the arrival of the human was delayed, the spectral parameters were comparable to those during isolation. This shows that vocal expressions in piglets during anticipation are specific to the expected reward. Vocal expressions-both their temporal and spectral features- are thus a good way to explore the emotional state of piglets during the anticipation of challenging events.

Conditions for assessing cortisol in sheep: the total form in blood v. the free form in saliva.

Cortisol is often used as a stress indicator in animal behaviour research. Cortisol is commonly measured in plasma and can also be measured in saliva. Saliva contains only the free form of cortisol, which is biologically active, and saliva sampling is not invasive and may therefore be less stressful. Our study aims to guide the choice between the measurements of cortisol in plasma v. saliva depending on experimental conditions. We analysed the effect of the level of cortisol in plasma on the concentration of cortisol in saliva compared to plasma and the effect of saliva sampling v. jugular venepuncture on the cortisol response. In Experiment 1, blood and saliva were collected simultaneously under conditions in which the expected cortisol release in blood varied: in an undisturbed situation or after the isolation of lambs from their pens or the administration of exogenous ACTH (six animals per treatment). In Experiment 2, we subjected lambs to saliva sampling, venepuncture or neither of these for 8 days to evaluate how stressful the sampling method was and whether the animals habituated to it by comparing the responses between the first and last days (four animals per treatment). All animals were equipped with jugular catheters to allow regular blood sampling without disturbance. Samples were collected 15 min before any treatment was applied, then at various time points up to 135 min in Experiment 1 and 45 min in Experiment 2. In Experiment 1, we observed a strong correlation between salivary and plasma cortisol concentrations (r = 0.81, P < 0.001). The ratio between salivary and plasma cortisol concentrations was 0.106 on average. This ratio was higher and more variable when the cortisol concentration in plasma was below 55 nmol/l. In Experiment 2, venepuncture induced a larger cortisol response than saliva sampling or no intervention on day 1 (P < 0.02); this difference was not observed on day 8, suggesting that sheep habituated to venepuncture. We recommend the measurement of cortisol in saliva to avoid stressing animals. However, when the expected concentration in plasma is below 55 nmol/l, the cortisol in saliva will reflect only the free fraction of the cortisol, which may be a limitation if the focus of the experiment is on total cortisol. In addition, if cortisol is measured in plasma and blood is collected by venepuncture, we recommend that sheep be habituated to venepuncture, at least to the handling required for a venepuncture.

Spatial distance and reactivity traits alter the positive perception of brushing by ewes.

Gentle handling seems to elicit positive states in sheep. The study investigated whether spatial distance alters sheep responses to brushing and whether spatial distance is influenced by reactivity. Twenty Romane ewes were assessed in three sessions: in Sessions 1 and 3, one grid separated the test animal from pen mates, with no distance between them, and in Session 2 two grids separated the test animal from pen mates by a distance of about 1.7 m. Ewes had been genetically selected for low (R-) or high (R+) behavioural reactivity to social isolation. Body postures, head orientation, ear postures, closed and half-closed eyes, tail wagging and feeding behaviour, in addition to heart rate (HR) and HR variability, as the root mean square of successive differences (RMSSD), standard deviation of all normal-to-normal (NN) intervals (SDNN), RMSSD/SDNN ratio and ratio between low-frequency (LF) and high-frequency (HF) powers (LF/HF) were assessed. Data were analysed using generalized linear models and linear mixed models. Session, genetic line and phase (pre-, brushing and post-brushing) were considered fixed effects. Increased distance in Session 2 might not have influenced ewes' responses. Fewer changes in ear postures were noted in Session 3 than 1 (P<0.01), suggesting that ewes were more relaxed in Session 3. The RMSSD/SDNN ratio was higher mainly during brushing in Sessions 1 and 3 (P<0.05), indicating that ewes were more relaxed during brushing, and at no distance between pen mates. However, spatial distance influenced R- and R+ ewes' responses; R+ ewes performed more asymmetric ear postures in Session 2 than 1 and 3 (P<0.01), and in Session 3 than 1 (P<0.01), indicating that spatial distance had a negative effect on R+ ewes. Low reactive ewes spent less time on horizontal ear postures in Session 2 than 1 and 3 (P<0.01), and R+ ewes spent more time on horizontal postures in Session 1 than 3 (P<0.01). Curiously, R- ewes spent more time eating and ruminating in Session 3 than 1 (P<0.01), and in Session 2 than 1 and 3 (P<0.01), whereas R+ ewes ate and ruminated more in Session 1 than 3 (P<0.05). Higher HR was found among R- ewes in Session 2 than 1 and 3, and in Session 3 than 1 (P<0.01). High reactive ewes showed higher HR in Session 1 than 3 (P<0.01). The findings suggest that the social context might influence sheep responses to gentle handling, and the effects depend on their reactivity traits.

A multiparametric approach to discriminate the impacts of different degrees of invasiveness of surgical procedures in sheep.

Traumatic situations in animals induce responses including pain, expressed through behavioural and physiological pathways such as inflammation, oxidative stress, hypothalamic-pituitary-adrenal (HPA) axis and autonomic nervous system. As some of these systems can also be activated during excitement and situations with a positive valence, their use as a means to assess pain response is difficult. We explored (i) how these five aforementioned pathways change in sheep exposed to various degrees of invasiveness of surgical procedures despite a therapeutic regimen and (ii) whether a multiparametric analysis that combines information from these five pathways enhances the discrimination between these situations, and estimates the relative importance of these pathways in the response. We used 24 adult sheep split into four treatments: Control (C; no fasting, no anaesthesia, no surgery), Sham (S; fasting, anaesthesia, no surgery), Rumen Canulation (R; fasting, anaesthesia, rumen cannulation) and Rumen-Duodenal-Ileum cannulation (RDI; fasting, anaesthesia, cannulation of the rumen, duodenum and ileum). Sheep' responses were measured for 5 days after surgery. When considering each behavioural or physiological pathway independently, discrimination between treatments was acceptable, its sensitivity (Se) ranging from 0% to 100%, and its specificity (Sp) ranging from 62% to 100%. The multiparametric analysis gathering information from the five pathways enhanced the effectiveness of discrimination between treatments (Se, 50% to 100%; Sp, 82% to 100%), and gave additional information on the relative contribution of each pathway to the global sheep response. Sheep global response was higher when exposed to a surgery, and increased with the surgery invasiveness. This response relied mostly on inflammation (absolute correlation for haptoglobin, 0.89), HPA (cortisol, 0.85) and behaviour (antalgic postures, 0.85). The multiparametric approach seems to be a promising tool to discriminate between different degrees of invasiveness of surgical procedures.

Effects of a chronic stress treatment on vaccinal response in lambs.

Farming 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.

Genotype by environment interactions for behavioral reactivity in sheep.

In sheep, social reactivity and reactivity to humans are relevant behavioral responses that are used to investigate the behavioral adaptation of farm animals to various rearing conditions. Such traits were previously reported as heritable and associated with several QTLs. However, few behavior-related genotype by environment (G × E) interactions have been reported to date. The experiment was performed on 2,989 male and female lambs issued from 30 sires. Every sire had progeny reared under both intensive and extensive conditions. After weaning, all lambs were individually exposed to two standardized behavioral tests. A broad range of behaviors including vocalizations, locomotion, localization, vigilance, and flight distance were assessed. Two complementary statistic approaches, with and without assumptions on the biological significance of behaviors, were performed to investigate social reactivity and reactivity to humans. G × E interactions were investigated based on the genetic correlations estimated for each factor or trait between farming conditions; those significantly different from 1 indicating a G × E. Environmental effects showed that social reactivity and reactivity to humans were higher in intensively reared lambs. The heritability of factors or traits used to measure social reactivity and reactivity to humans was similar in both rearing conditions. Estimated heritabilities were high for vocalizations in response to social isolation, moderate for locomotion and vigilance in response to social isolation, and low for both flight distance to an approaching human and proximity to a motionless human. No significant G × E interaction was found for vocalizations. G × E interactions were found for locomotion, vigilance and flight distance. Genetic correlations between both environments were low to moderate for vigilance, locomotion and flight distance. Vocalization in response to social isolation with or without human presence was identified as a robust trait and could be used to improve sheep sociability, independently of the environment. A G × E interaction was observed for behavioral reactivity to humans. Although moderate, the genetic correlation for this trait between intensive and extensive conditions could be used to select sires in the same environment by taking into account the G × E and to produce in different environments progenies that are less reactive to humans.

Environmental enrichment reduces behavioural alterations induced by chronic stress in Japanese quail.

Animals perceiving repeated aversive events can become chronically stressed. Chronic activation of the hypothalamic-pituitary-adrenal (HPA) axis can have deleterious consequences on physiological parameters (e.g. BW, blood chemistry) and behaviour (e.g. emotional reactivity, stereotypies, cognition). Environmental enrichment (EE) can be a mean to reduce animal stress and to improve welfare. The aim of this study was first, to assess the effects of EE in battery cages on the behaviour of young Japanese quail and second, to evaluate the impact of EE on quail exposed to chronic stress. The experiment involved quail housed in EE cages and submitted or not to a chronic stress procedure (CSP) (EE cages, control quail: n=16, CSP quail: n=14) and quail housed in standard cages and exposed or not to the CSP (standard non-EE cages, control quail: n=12, CSP quail: n=16). Our procedure consisted of repeated aversive events (e.g. ventilators, delaying access to food, physical restraint, noise) presented two to five times per 24 h, randomly, for 15 days. During CSP, EE improved quail's welfare as their stereotypic pacing decreased and they rested more. CSP decreased exploration in all quail. After the end of CSP, quail presented increased emotional reactivity in emergence test. However, the effect of EE varied with test. Finally, chronic stress effects on comfort behaviours in the emergence test were alleviated by EE. These results indicate that EE can alleviate some aspects of behavioural alterations induced by CSP.

How assessing relationships between emotions and cognition can improve farm animal welfare.

The assessment of farm animal welfare requires a good understanding of the animals' affective experiences, including their emotions. Emotions are transient reactions to short-term triggering events and can accumulate to cause longer-lasting affective states, which represent good or bad welfare. Cognition refers to the mechanisms by which animals acquire, process, store and act on information from the environment. The objective of this paper is to highlight the two-way relationships between emotions and cognition that were originally identified in human psychology, and to describe in what ways these can be used to better access affective experiences in farm animals. The first section describes a recent experimental approach based on the cognitive processes that the animal uses to evaluate its environment. This approach offers an integrative and functional framework to assess the animal's emotions more effectively. The second section focuses on the influence of emotions on cognitive processes and describes recently developed methodologies based on that relationship, which may enable an assessment of long-term affective states in animals. The last section discusses the relevance of behavioural strategies to improve welfare in animals by taking their cognitive skills into account. Specific cognitive processes eliciting positive emotions will be emphasised. Research into affective states of animals is progressing rapidly and the ability to scientifically access animal feelings should contribute to the development of innovative farming practices based on the animals' sentience and their cognitive skills in order to truly improve their welfare.

The valence of the long-lasting emotional experiences with various handlers modulates discrimination and generalization of individual humans in sheep.

Between-farm variation in animal reactions to humans can reflect different management styles and behavioral tendencies among farmers. Animals are well known to discriminate among humans, but less clear is the key issue of whether they more or less easily generalize their experience from specific humans to others depending on management style. Here, we chose 2 contrasted management styles by known handlers: "gentle" management, that is, long-lasting exposure to positive human interactions (with limited negative interactions), and "aversive" management including long-lasting exposure to various negative human interactions (with only food delivery considered a positive interaction) and aversive events. Over a period of 19 wk, 15 female lambs were exposed to the gentle management treatment ("gently treated" group) and another 15 lambs ("aversively treated" group) were exposed to the aversive management treatment. To facilitate discrimination by animals, experimenters wore white clothes for aversive events and green clothes for farming handling (positive handling and feeding for the gently treated group and only feeding for the aversively treated group). Sheep perception of the human was assessed after the management period by submitting lambs from each group to 2 standardized tests: 1) the presence of a stationary human (familiar human in white vs. familiar human in green vs. unknown human) and 2) the presence of a moving human (familiar human in white vs. familiar human in green vs. unknown human). As expected, during the stationary human test, aversively treated lambs spent less time in the human zone (P<0.0001), showed greater latency to approach the human (P=0.05), and had fewer contacts with the human (P=0.05) than gently treated lambs. During the moving human test, aversively treated lambs also showed a greater escape distance from humans than gently treated lambs (P<0.0001). Aversively treated lambs showed the same fear responses towards familiar and unknown humans and tended to generalize their aversive experiences with one handler to all humans. In contrast, gently treated lambs seemed to discriminate familiar humans from unfamiliar humans. Different management styles could modulate farm generalization to humans in farm animals.

Long-term exposure to unpredictable and uncontrollable aversive events alters fearfulness in sheep.

Numerous studies have investigated the emotional effects of various acute, potentially alarming events in animals, but little is known about how an accumulation of emotional experiences affects fearfulness. Fearfulness is a temperament trait that characterizes the propensity of an individual to be frightened by a variety of alarming events. The aim of this study was to investigate a putative alteration of fearfulness in sheep repeatedly exposed to various aversive events. Forty-eight 5-month-old female lambs were used. Over a period of 6 weeks, 24 of them (treated group) were exposed daily to various unpredictable and uncontrollable aversive events related to predatory cues, social context and negative handling that can occur under farming conditions. The other 24 lambs (control group) were housed in standard farming conditions (predictable food distribution and group handling). Fearfulness (behavioural and physiological responses) was assessed before and after the treatment period by subjecting the lambs to three standardized tests: individual exposure to suddenness and then to novelty in a test arena, and group exposure to a motionless human in the home pen. As biomarkers of stress, leukocyte counts, heart rate and cortisol concentrations were measured in the lambs in their home pens. Before the treatment, the emotional responses of the groups did not differ. After the treatment, treated lambs approached the human less often, had less contact with the novel object and vocalized more than controls in individual tests, suggesting that long-term exposure to unpredictable and uncontrollable aversive events increases subsequent fearfulness in sheep. In addition, treated lambs had lower leukocyte counts, heart rate and cortisol levels, pointing to a chronic stress state. These findings suggest that increased fearfulness may be used as a sign of chronic stress in farm animals.

Effects of feed deprivation on behavioral reactivity and physiological status in Holstein cattle.

The present study evaluated whether feed deprivation can increase reactivity to stressful events, such as those that can occur at slaughter. Therefore, effects of 30 h of feed deprivation on behavior, including reactions to psychological stressors, and physiological status in cattle were determined. Sixteen Holstein cows (Exp. 1) and 32 Holstein heifers (Exp. 2) were either fed (FE) or 30-h feed deprived (FD). Throughout the first day of feed deprivation and during evening feed distribution to control animals, FD heifers and cows were more active than controls (P < 0.05). In Exp. 1, during a feeding test, in response to a sudden air blast arising from the bucket from which the cow was feeding, FD cows showed a longer latency to return to feed (P = 0.0002), spent less time in the bucket air blast zone (P = 0.008) and less time motionless (P = 0.03), and tended to withdraw over a longer distance (P = 0.07) than FE cows. In Exp. 2, during a reactivity test, FD heifers spent more (P = 0.0001) time motionless in response to social isolation than FE heifers. In Exp. 2, one-half of the FE and FD heifers were subjected to an additional physical and psychological stressor just before the reactivity test by driving them for 5 min through a labyrinth. Within heifers subjected to the additional stressor, FD heifers were less accepting of being detained (P = 0.05) and stroked (P = 0.003) by a familiar stockperson in a corner of the test arena. Compared with FE animals, FD heifers and FD cows had greater plasma cortisol concentrations (P < 0.05). Feed-deprived cows also had reduced ß-hydroxybutyrate concentrations (P = 0.02) compared with FE cows. Thus, in cattle, FD influenced some of the classical indicators of energy metabolism and exacerbated reactivity to sudden events. In addition, when additional stressors were applied, FD cattle were more reluctant to accept handling. Results indicate that a multifactorial origin of stressors during the slaughter period may synergistically increase psychological stress of cattle.

Higher inherent fearfulness potentiates the effects of chronic stress in the Japanese quail.

There is considerable variability in the susceptibility of individuals to the adverse effects of chronic stress. In humans and other mammals, individual traits such as high anxiety are proposed as a vulnerability factor for the development of stress-related disorders. In the present study, we tested whether a similar behavioural trait in birds, higher emotional reactivity, also favours the occurrence of chronic stress-related behavioural and physiological dysfunction. For this, lines of Japanese quail divergently selected for a typical fear response in birds, the duration of tonic immobility, were subjected to unpredictable aversive stimulation over 2 weeks. Previous studies demonstrate that the selection program modifies the general underlying emotionality of the birds rather than exerting its effect only on tonic immobility. Interestingly, only birds selected for their higher emotionality exhibited significantly enhanced latency to first step and decreased locomotor activity in the open-field test after exposure to chronic stress compared to non-stressed control birds. This effect of chronic stress was selective for the tested dimension of bird emotional reactivity because there was no observed effect on the tonic immobility response. Moreover, chronically stressed birds selected for their higher emotionality exhibited significantly decreased basal corticosterone levels, a physiological marker of stress. These findings show that chronic stress is associated with changes in emotional reactivity and related physiological markers in birds. They also highlight emotional reactivity as an important predisposing factor for the occurrence of the adverse effects of chronic stress in birds.

The ability of lambs to form expectations and the emotional consequences of a discrepancy from their expectations.

Appraisal theories developed in cognitive psychology are used here to attempt to better understand emotional experiences in animals. We investigated whether lambs are able to form expectations and whether their emotional responses are affected by situations discrepant from the expectations they may have formed. Forty-five female lambs were trained to obtain a small or a large amount of food reward by performing an operant task (introducing their muzzle into a hole). Then, half the lambs were shifted to the large or the small reward (i.e. positive or negative shift respectively), while the remaining half continued to get the same amount of reward. Thereafter, the lambs previously submitted to a reward change were shifted back to their initial amount of reward (i.e. successive shifts) while the lambs previously maintained on the same amount of reward were subjected to extinction (no reward, thus a negative shift). Behavior, cortisol levels and cardiac activity were analyzed, and the treatments were compared with ANOVAs for mixed models. When the amount of reward delivered was decreased, the lambs showed more locomotor activity and performed the operant task at a higher frequency but less efficiently, and there was a decrease in the parasympathetic influence on their cardiac activity. These responses were exacerbated when the negative shift followed a positive one. Similar responses were observed under extinction, and these responses were more pronounced when animals were trained with a large amount of reward before extinction. In response to a positive shift, we noticed a decrease in the frequency of the attempted operant task; this occurred only when the positive shift followed a negative one. Variations in plasma cortisol were not consistent with changes in the amount of reward. This study shows that lambs evaluate a reward according to their previous experience with that reward. They are able to form expectations, and a discrepancy from these expectations influences emotional responses, especially in the case of a negative shift. Given the appraisal criteria used by lambs and the matching emotions, we can assume that the emotional response to a negative shift expressed by lambs could reflect the despair caused by frustration.

Stray voltage threshold is better determined under choice test conditions in sheep.

Stray voltage (usually <10 V) can occur in farms. However, very little information is available related to sheep. In addition, little work has been carried out on the effects of the contextual conditions under which the animals are submitted to stray voltage. The aims of this study were (i) to determine the threshold voltage at which lambs start to express avoidance behaviour and (ii) to test if the contextual conditions (i.e. choice v. no-choice conditions) influence the determination of the threshold voltage inducing avoidance behaviour. Six-month-old female lambs fed ad libitum were trained to eat palatable pellets from one or two metallic feeders situated at the end of a 4-m long raceway. Voltage was then applied during a 2-min test to either the only feeder available (no-choice test, 1F, n = 13) or to the first of the two feeders in which the lamb started to eat (choice test, 2F, n = 13). The 1F lambs had to stop eating to avoid the voltage, whereas the 2F lambs were allowed to switch to the non-electrified feeder to carry on eating without any stray voltage. Stray voltage was applied every day, in steps of 0.5 V (AC, 50 Hz), from 0 up to 8 V. For voltages higher than 4.5 V, 2F lambs spent less time eating and ate less in the electrified feeder compared with the non-electrified feeder, and their latency to switch to the non-electrified feeder was shorter. In addition, a transient modification of behaviour was observed at 1.5 V. For 1F lambs, a decrease in the quantity of feed eaten was found for voltages higher than 5 V, although the time spent eating in the electrified feeder was not modified. Finally, 1F lambs urinated more during or just after the 2 min test than 2F lambs for voltages above 5 V. Although lambs with no choice experienced stray voltage as a negative event (increased occurrence of urination), they carried on eating in the electrified feeder whatever the voltage. Therefore, the contextual conditions in which animals are exposed to stray voltage influence their subsequent reactions: the first clear behavioural reaction threshold is easier to detect in choice than in no-choice conditions.

Behavioural and physiological responses of lambs to controllable vs. uncontrollable aversive events.

The identification of the cognitive processing by which animals evaluate their environment helps to predict situations detrimental to their welfare. Appraisal theories developed in cognitive psychology offer a framework to study such cognitive processing. Here we investigated whether the controllability of an aversive event (an airblast and a sliding grate preventing access to a food reward) affected emotional responses in lambs. The animals could (vs. could not) interrupt the aversive event and thus gain access to food by performing an operant task (placing their muzzle in an aperture). Among lambs trained to perform the operant task, seven learnt it completely and six partially (i.e. they approached their muzzle to the aperture). Each of the 13 lambs that learnt the task completely or partially was paired with a "yoked" partner not taught how to interrupt the aversive event. Behaviour, cortisol and cardiac activity were recorded and the groups were compared with ANOVAs for mixed models. Compared with the lambs unable to interrupt the aversive event, the lambs taught to control it were more inclined to enter and stay in the test arena, and more inclined to eat there. These differences were generally more marked in pairs where the operant task had been fully learnt. An occurrence of the aversive event was followed by a transient backwards-pointing position of the ears and an increased heart rate in all the lambs. These responses were less pronounced in controlling lambs that had completely learnt the operant task. We show that an aversive situation is perceived as less stressful by sheep when they can exert control over it and this effect depends on the degree of control.

Individual and social determinants of spontaneous group movements in cattle and sheep.

Group-living animals travel together to collectively exploit the resources of their environment. This study investigates how social relationships and individual temperament traits affect movement orders in domestic cattle and sheep. We analysed spontaneous group movements occurring at pasture after a resting period in a group of 15 18-month-old Charolais heifers and a group of 19 1-year-old Romane ewe-lambs. For each species, animals had similar social experience and no kinship ties. Before that, animals were observed within the group to establish their social status (e.g. dominance and preferential relationships, and sociability), then in individual tests in order to assess their emotional traits. In both species, most individuals could initiate a group movement but some individuals were more successful than others in recruiting the rest of the group. Ewe-lambs, and to a lesser extent heifers, held preferential positions during travel. We did not find any significant correlations in either species between animal order and their position in the dominance hierarchy (heifers: P = 0.438; ewe-lambs: P = 0.574) while individuals linked by preferential bonds frequently followed each other during group movements (heifers: P < 0.001; ewe-lambs: P < 0.001). With regard to social traits, heifers with a low cohesion index, and with a lower number of partners with whom they develop frequent affinitive interactions, acted more frequently as 'first movers' (P = 0.040 and 0.023, respectively), as well as did ewe-lambs with a high spatial independency index (P = 0.002). Ewe-lambs with the highest cohesion indices were more frequently observed in front of the group while moving halfway between departure and arrival (P = 0.028). We did not find significant correlations between individual positions during group movements and emotional traits such as reactivity, boldness and fearfulness. We conclude that preferential bonds and individual traits related to social dependence were more influential in spontaneous group movements at pasture than were emotional traits and dominance status.

Positive attitudes of farmers and pen-group conservation reduce adverse reactions of bulls during transfer for slaughter.

Transfer to slaughter may be very stressful for cattle and negatively affect their ultimate carcass pH. A potential link between farmers' attitudes, farmers' behaviour, responses of animals to handling and carcass pH in beef bull production was questioned. Whether carcass pH depends on experiences in handling and social mixing was analysed. We conducted a survey on commercial farms where we questioned farmers on their work and beliefs about bulls. Farmers' behaviour with bulls during a test and bulls' behaviour during loading in the truck for transport to the slaughterhouse were observed. The ultimate carcass pH was measured. Farmers tended to behave more gently with their bulls when they had positive attitudes towards gentle contacts with bulls (P = 0.07). The loading of bulls in the truck tended to be more difficult when the farmer was more ready to approach his bulls (P = 0.07). Carcass pH was higher for bulls that had not been transferred from a breeding to a finishing unit (P = 0.03). It tended to be higher when the farmer did not display a gentle behaviour (P = 0.09). The link between farmers' attitudes and farmers' behaviour and the lower meat pH resulting from a gentle farmers' behaviour during finishing are consistent with previous findings in pig, veal or dairy productions. However, the present links were weaker than in the other productions, probably due to the low frequency of close contacts between farmers and beef bulls. When loading bulls into a truck, handlers use the tendency of animals to avoid people, hence overly positive behaviour with the animals during finishing may result in more difficulties at loading. In that case, use of alternative driving aids should be recommended. Our results on carcass pH suggest some habituation to transport among bulls transferred between breeding and finishing, even though the two experiences are several months apart. In view of our results, it seems that contacts with bulls, when they are needed, should be gentle.

A critical review of fear tests used on cattle, pigs, sheep, poultry and horses.

Fear is arguably the most commonly investigated emotion in domestic animals. In the current review we attempt to establish the level of repeatability and validity found for fear tests used on cattle, pigs, sheep and goats, poultry and horses. We focus the review on the three most common types of fear tests: the arena test (open field), the novel object test, and the restraint test. For some tests, e.g. tonic immobility in poultry, there is a good and broad literature on factors that affect the outcome of the test, the validity of the test and its age dependency. However, there are comparatively few of these well defined and validated tests and what is especially missing for most tests is information on the robustness, i.e., what aspects can be changed without affecting the validity of the tests. The relative absence of standardized tests hampers the development of applied ethology as a science.