Search

Summary Indiscriminate voiding of excreta by cattle contributes to greenhouse gas (GHG) emissions and soil and water contamination1,2. Emissions are higher in animal-friendly husbandry offering cattle more space2 — a trade-off we call the ‘climate killer conundrum'. Voiding in a specific location (latrine) would help resolve this dilemma by allowing ready capture and treatment of excreta under more spacious farming conditions. For urination, toileting requires self-control and coordination of a complex chain of behaviors including awareness of bladder fullness, overriding of excretory reflexes, selection of a latrine and intentional relaxation of the external urethral sphincter3. Attempts to train toileting in cattle have so far been only partly successful4–6, even though their excretion and associated neurophysiological control are similar to those in species capable of toileting3. Similarly, very young infants have been considered incapable of self-initiated voiding, but they can be taught with extensive training7. Using a backward chaining, reward-based training procedure, we here show that cattle can control their micturition reflex and use a latrine for urination. Such self-control provides evidence that animals can learn to respond to and reveal internal experiences via appropriately trained operant behaviors, thereby providing another way to explore their subjective states.

Both humans and nonhuman animals need to show self-control and wait for a larger or better reward instead of a smaller or less preferred but instant reward on an everyday basis. We investigated whether this ability undergoes ontogenetic development in domestic pigs (similar to what is known in human infants) by testing if and for how long nine- and 16-week-old pigs wait for a larger amount of their preferred reward. In a delay-of-gratification task, animals first learned that a small reward was hidden under a white cup and a large reward under a black cup, and then the delay to deliver the large reward was gradually increased. The results show that older pigs could wait longer for a larger reward than younger pigs (10.6 ± 1.3 s vs. 5.2 ± 1.5 s), thereby confirming our hypothesis of ontogenetic development of self-control in pigs. This self-control is likely to be regulated by the behavioural inhibition system and associated systems. Self-control or, more specifically the lack of it may be involved in the development of abnormal behaviours, not only in humans but also in animals. Therefore, research on self-control in decision-making might provide a new perspective on abnormal behaviours in captive animals.

The hypothalamic-pituitary-adrenal (HPA) axis is an important component of neuroendocrine stress regulation and coping behavior. Transcriptome profiles of the hypothalamus and adrenal gland were assessed to identify molecular pathways and candidate genes for coping behavior in pigs. Ten each of high- (HR) and low- (LR) reactive pigs (n = 20) were selected for expression profiling based haplotype information of a prominent QTL-region on SSC12 discovered in our previous genome-wide association study (GWAS) on coping behavior. Comparing the HR and LR pigs showed 692 differentially expressed genes (DEGs) in the adrenal gland and 853 DEGs in the hypothalamus, respectively. Interestingly, 47% (17 out of 36) of DEGs found in both tissues were located in GWAS regions identified on SSC12, indicating that there are significant functional positional candidate genes for coping behaviour. Pathway analysis assigned DEGs to glucocorticoid receptor signaling in the adrenal gland. Furthermore, oxidative phosphorylation, mitochondrial dysfunction, and NGF signaling as well as cholecystokinin/Gastrin-mediated were identified in the hypothalamus. We narrowed the list of candidate genes in GWAS regions by analyzing their DEGs in the HPA axis. The top identified transcripts, including ATP1B2, AURKB, MPDU1 and NDEL1 provide evidence for molecular correlates of coping behavior in GWAS regions.

Understanding animal emotions is an important scientific and ethical question but assessing emotional valence is still considered challenging. As the observation of lateralization (hemispheric asymmetries in structure and/or function) can provide insight into the underlying processes of the cognitive, physiological and behavioural components of emotions, it is a promising approach for studying them. The emotional valence hypothesis states that positive emotions are mostly processed by the left hemisphere, while negative emotions are mostly processed by the right hemisphere. Support for this hypothesis is still not conclusive; therefore, our study tested it in the context of visual laterality for viewing positive or negative emotionally conditioned stimuli. Ninety male piglets were either positively (food-reward) or negatively (mild punishment) conditioned to an object. Afterwards, the object was presented without the reinforcer under three different treatments: patch on the left or right eye (reducing input to the contralateral hemisphere) or patch between the eyes (the control). Monocular viewing had no clear effects on the negatively conditioned subjects. In contrast, in the positively conditioned group, covering the right eye caused a longer interruption of vocalization, a longer latency to touch the object, a shorter duration of exploring the arena and an increased vagal activity compared to the control. This suggests that reduced processing in the left hemisphere leads to heightened attention that is accompanied by a general orienting response, possibly resulting from a reduced positive appraisal. These findings therefore partially support the emotional valence hypothesis and suggest an important role of the left hemisphere in the quick recognition of a positive stimulus. This study demonstrated that investigating the lateralized processing of emotions can provide insight into the mechanisms of positive appraisal in animals.

Walking ability is related to motor co-ordination which, in rodents, can be assessed by an established test in pharmacological studies — the rotarod test. The purpose of this study was to evaluate a modified rotarod test for chickens and its relation to the often-used gait score system. At the end of their rearing period, we tested 138 male chickens (Gallus gallus domesticus) from three differing growth performance strains: Ross 308 (fast-growing; n = 46), Lohmann Dual (medium-growing; n = 46) and Lohmann Brown Plus (slow-growing; n = 46). First, the chickens’ gait scores were assessed and, immediately following this, they were placed gently onto a steady rod. The velocity of the rotating rod gradually increased, and the latency to leave the rod was recorded. By using a linear mixed model, we were able to show that the latency to leave the rotating rod was significantly predicted by the gait score. Fast-growing chickens had shorter durations on the rotating rod, and these durations were associated with gait score. We conclude that the rotarod test provides an objective alternative method for assessing walking ability in chickens without the need for intense observer training or the risk of observer biases and propose that this novel methodology has the potential to function as a precise, objective indicator of animal welfare.

The assessment of personality in farm animals and its relation to other behavioural and physiological traits is of growing scientific and practical interest. Therefore, the aims of the present study were first to assess the personality of dwarf goats in the context of the proactive/reactive dichotomy and second to elucidate cross-context correlations to other individual patterns in behaviour and physiology. We measured the behaviour of 108 Nigerian dwarf goats in repeated (two test periods within two weeks) open-field and novel-object tests to classify the subjects into proactive, reactive and intermediate personality types. In addition, we investigated the possible inter-relationships of inter-individual differences in personality with behaviours in other test situations and physiological measures (heart rate variability). To identify individual personality types, we selected the 11 most appropriate behavioural measures, identical in both test periods, from a total of 82 observed behaviours. Using these behaviours, we ran two separate principal component analyses (PCA1 and PCA2) for the two test periods. We found two main principal components (PCs), which were interpreted as “boldness” (PC1) and “activity” (PC2) and were identical in both PCAs. Based on PCA1, 30 goats could be grouped as the proactive, 25 as the reactive and 53 as the intermediate personality type. In PCA 2, 66 individuals (61%) showed a consistent personality type compared to PCA1. Goats that scored highly on PC2 were also more active in a social separation test, while no correlations were found between PC1 or PC2 and the dominance status. Regarding heart rate variability, the standard deviation of R-R intervals (SDNN) was positively correlated with PC2, while a negative correlation was found between PC1 and SDNN. PC2 was also positively correlated with weight gain. The present study is the first to quantify temporarily consistent and cross-context correlations of individual behavioural and physiological differences in goats. The relatively small number of animals that showed the same extreme behavioural phenotype in both test periods is in good agreement with studies on personality types in cattle and pigs and shows that intermediate and flexible personality types make up the main part of a population. The results provide new opportunities to investigate the inter-relationships of inter-individual differences in personality traits with other physiological measures and cognitive abilities in goats.

In humans, speech perception is lateralized, with the left hemisphere of the brain dominant in processing the communicative content and the right hemisphere dominant in processing the emotional content. However, still little is known about such a division of tasks in other species. We therefore investigated lateralized processing of communicative and emotionally relevant calls in a social mammal, the pig (Sus scrofa). Based on the contralateral connection between ears and hemispheres, we compared the behavioural and cardiac responses of 36 young male pigs during binaural and monaural (left or right) playback to the same sounds. The playback stimuli were calls of social isolation and physical restraint, whose communicative and emotional relevance, respectively, were validated prior to the test by acoustic analyses and during binaural playbacks. There were indications of lateralized processing mainly in the initial detection (left head-turn bias, indicating right hemispheric dominance) of the more emotionally relevant restraint calls. Conversely, there were indications of lateralized processing only in the appraisal (increased attention during playback to the right ear) of the more communicative relevant isolation calls. This implies differential involvement of the hemispheres in the auditory processing of vocalizations in pigs and thereby hints at similarities in the auditory processing of vocal communication in non-human animals and speech in humans. Therefore, these findings provide interesting new insight in the evolution of human language and auditory lateralization.

Simple Summary The mixing of bovine faeces and urine leads to climate-damaging ammonia emissions. If cattle could be taught to use a latrine, this would reduce the area of emissions, the separation of excreta could easily be accomplished by mechanical means, and animal health could be improved. Attempts to train toileting in cattle have shown limited success. In children, toileting is trained mainly by (i) interrupting voiding that starts outside the toilet, then taking the child to the toilet and rewarding the resumption of excretion, or (ii) placing the child on the toilet, waiting for urination/defecation and rewarding appropriate excretory behaviour. The first method is reported to be more successful. Thus, a similar procedure was evaluated for training latrine use for urination in calves. On 95% of occasions, the calves inhibited or stopped urination when receiving a signal to move to the latrine, and on 65% of occasions, they reinitiated urination in the latrine. Furthermore, during 63% of urinations in the latrine, the calves oriented towards the reward location before any food was delivered, providing additional evidence that calves can be successfully toilet trained with food rewards. Abstract Untrained cattle do not defecate or urinate in defined locations. The toilet training of cattle would allow urine and faeces to be separated and stored, reducing climate-damaging emissions and improving animal health. In a proof-of-concept study, we evaluated a novel protocol for toilet training in cattle. Five heifer calves (and yoked controls) were trained in the voluntary (operant) behaviours of a toileting chain. Then, reflexive urinating responses were incorporated into the chain, with toileting signalled by a tactile (vibratory) stimulus. On 95% of occasions, the calves inhibited/interrupted urination when receiving the stimulus, and on 65% of these occasions, reinitiated urination in the latrine. Furthermore, during 63% of urinations in the latrine, the calves oriented to the reward location before any food was delivered, providing additional evidence that calves can be successfully toilet trained with food rewards. Yoked controls failed to learn most of the operant elements and all the reflexive responses of toilet training. The results show that reflexive behaviours can be incorporated into voluntary toileting sequences with cattle and extend the range of species that can be toilet trained. Future refinement of the protocol to allow training under practical farm conditions offers the potential to mitigate climate damage and improve animal health.

The domestic fowl (Gallus gallus f. dom.) is highly motivated to roost on elevated structures. Previous studies indicated that broiler chickens hardly use elevated perches but frequently use elevated platforms. However, it is unclear which height and type of elevated structures broilers prefer at various daytimes. We investigated the use of elevated perches and grids varying in height (10, 30, and 50 cm above the floor) by chickens of 3 strains differing in growth performance. In 2 successive trials, male chickens of Ross 308 (Ross, fast growing, n = 200), Lohmann Dual (Dual, medium growing, n = 200), and Lohmann Brown Plus (LB, slow growing, n = 200) were tested in 12 experimental compartments (each strain in 4 compartments), respectively. Usage of structures was recorded on video and analyzed with time-sampling observation for each week of age during dawn, the light period, dusk, and the dark period. In addition, behavioral activity was measured with an antenna-transponder system. The results showed that Ross and Dual chickens preferred grids to perches throughout the entire observation period. With increasing age, chickens of all strains increasingly used the elevated structures during all daytimes. In contrast to Dual and LB, Ross chickens reduced the use of structures from the 3rd to 4th week of age during the light but not the dark period. Additionally, during the dark period, chickens of all 3 strains at the end of fattening period used elevated structures at 50 cm height most often. The behavioral activity decreased significantly in all 3 strains but was much lower in Ross chickens compared with Dual and LB. The results indicated that chickens are motivated to roost at nighttime on high-elevated and suitable structures such as grids. Further studies are needed to assess the space requirements for elevated structures that should be offered to chickens.

The reliable detection of estrus is an important scientific and practical challenge in dairy cattle farming. Female vocalization may indicate reproductive status, and preliminary evidence suggests that this information can be used to detect estrus in dairy cattle. The aim of this study was to associate the changes in the vocalization rate of dairy heifers with behavioral estrus indicators as well as test the influence of the type of estrus (natural estrus vs. superovulation-induced estrus). We analyzed 6 predefined estrus-related behavior patterns (standing to be mounted, head-side mounting, active mounting, chin resting, being mounted while not standing, and active sniffing in the anogenital region) and vocalization rates in the peri-estrus period (day of estrus ± 1 d) of 12 German Holstein heifers using audio-visual recordings. Each heifer was observed under natural estrus and a consecutive superovulation induced by FSH and cloprostenol. Estrus was determined by behavioral patterns and confirmed by clinical examination (vaginoscopy and ultrasound imaging of the ovaries) as well as by the concentration of peripheral progesterone. Estrus behavior and vocalization rates were analyzed in 3-h intervals (an average of 19 intervals for each heifer), and an estrus score was calculated based on the 6 behaviors. The interval with the highest estrus score (I0) was considered the estrus climax. We demonstrated similar time courses for the estrus score and vocalization rate independent of estrus type. However, in natural estrus, the maximum vocalization rate (±SE) occurred in the interval before estrus climax (I−1; 42.58 ± 21.89) and was significantly higher than that in any other interval except estrus climax (I0; 27.58 ± 9.76). During natural estrus, the vocalization rate was significantly higher within the interval before estrus climax (I−1; 42.58 ± 21.89 vs. 11.58 ± 5.51) than under superovulation. The results underscore the potential use of vocalization rate as a suitable indicator of estrus climax in automated estrus detection devices. Further studies and technical development are required to record and process individual vocalization rates.

Motor lateralization is hypothesized to depend on the complexity of the motor function, but it might at the same time reflect hemispheric dominance within an individual across motor functions. We investigated possible motor lateralization patterns in four motor functions of different complexity (snout use in a manipulative task, foot use in two-stepping tasks and tail curling) in the domestic pig, a tetrapod species relevant as farm animal but also as a model in human neuroscience. A significant majority of our sample showed individual biases for manipulation with their snout and for curling their tail. Interestingly, the tail curling was lateralized towards the right at the population level and showed stronger lateralization patterns than the snout. Using a cluster analysis with combined tail and snout laterality, we identified groups of individuals with different lateralization patterns across motor functions that potentially reflect the individuals' hemispheric dominance. To conclude, our results suggest that pigs show lateralization patterns that depend on the motor function and on the individual. Such individual lateralization patterns might have broader implications for animal personality and welfare. Our study lays the methodological groundwork for future research on laterality in pigs.

Since the introduction of the backtest for the early detection of coping strategies in piglets by Hessing in the 1990s, this behavioural test has been intensively investigated with ambiguous results. One possible explanation for this lack of consistency might be the different classification methods used in many studies, so the first aim of this research was to investigate the inter-situational consistency of backtest behaviour in a set of 120 piglets. Through a correlation analysis, we related backtest behaviour with behaviours in other test situations (mixing/dominance; group testing: human approach test (HAT), novel object test (NOT), open door test (ODT); and individual testing: open field test (OFT)). Second, in a larger number of piglets (n = 3555), we investigated four different classification methods that use different parameters (latency, duration, and frequency) and different test repetitions (1, 2, 3, and 4). We then tested the effect of classifying the animals according to each method and analysing their distribution across categories and the variance in the behavioural data using the 120-piglet dataset (category analysis). Finally, we validated the results of the category analysis with the results of the correlation analysis. The correlation analysis revealed weak (dominance: rS

The assessment and provision of welfare in farm animals has become a major issue in animal science. A key element for providing good welfare is the enabling of positive affective states in the animals. As the serotonergic system plays a central role in regulating affective behavior, an increase in centrally available serotonin (5-HT) via dietary supplementation of its precursor, tryptophan (TRP), might be an approach to induce positive affective states. Therefore, the aim of our study was to investigate the effects of dietary TRP supplementation on brain TRP metabolism and 5-HT levels but also on affective state and behavioral reactivity in pigs. All subjects were fed a standard diet until 8 weeks of age, then feed was changed for all animals, with half the animals (control) receiving a diet with the recommended TRP content (2.5 g/kg), whereas the other half (TRP+) received a TRP-enriched diet (10.2 g/kg). In part 1 of our study, we investigated the effects of the dietary TRP supplementation on TRP metabolism in brain areas related to affective and cognitive processing. We found significantly increased concentrations of TRP and its metabolites in nearly all analyzed brain tissues. In part 2 of our study, we analyzed the effects of these alterations on the affective state as measured in a cognitive bias test, namely the spatial judgment task, but also on behavioral reactivity as measured in a combined open field/novel object test. The TRP enrichment revealed no significant behavioral changes in the open field/novel object tests. In the spatial judgment task, the TRP+ group showed more pessimistic behavior after dietary change than before. Thus, our results do not support the suggestion that TRP supplementation induces positive affective states and thus improves animal welfare in pigs.

Public concern for farm animal welfare calls for reliable scientific tools to measure it. Measuring cognitive bias, i.e., the influence of affective states on cognitive processing, has gained importance during recent years. The one most often adapted experimental design to test cognitive bias in non-human animals is the spatial judgement task, where animals must judge a goal box/pot based on its location. First, they learn to discriminate between a positively reinforced and a negatively reinforced location, and then they are confronted with ambiguous, intermediate locations. The responses to these so-called probe cues are assumed to be influenced by the animal’s affective state. Current methods for the assessment of cognitive bias in domestic pigs, one of the most intensively housed farm animal species in Europe, still need to be refined and validated. Hence, we developed an improved, reliable design to test pigs repeatedly and induce graded responses to graded probe cues. For this, we used a spatial judgement task in a go/no-go paradigm with partial reinforcement and a mildly aversive negative reinforcer. A total of 16 female juvenile German Landrace pigs underwent discrimination learning of the rewarded vs. punished goal box location; this was then repeatedly tested on three probe locations in between (eight times in four weeks). The subjects learned to discriminate between the two reference locations and showed graded responses (latency to open the goal box) to the probe locations. Analyses of the subjects’ general behaviour implied that additional information on the animals’ state can be derived. The subjects showed no signs of learning with respect to the outcome of probe cues but exhibited stable response levels during test weeks two to four. In conclusion, the design presented in this paper is suitable for spatial judgement tasks in domestic pigs. After successful validation it might be used for testing affective valence based on judgement bias and hence can contribute to our understanding of the welfare of this intensively farmed species.

Typically, cattle urinate and defecate with little or no control over time and place. The resulting excreta contributes to a range of adverse effects on the environment and the animals themselves. These adverse effects could be substantially ameliorated if livestock could be toilet trained. Toilet training requires an animal to suppress impending voiding (a reflexive-like behavior), move to a latrine (voluntary behavior) and reinitiate voiding. Here, we review the neurophysiological processes and learning mechanisms regulating toileting. The suppression and initiation of voiding occur primarily via the coordinated activity of smooth and striated anal and urinary sphincter muscles. The autonomic and somatic nervous systems, along with central processes, regulate these muscles. In several mammalian species, voluntary control of the sphincters has been demonstrated using classical and/or operant conditioning. In this review, we demonstrate that the neurophysiological and behavioral regulation of voiding in cattle is likely to be similarly conditionable. The management of excreta deposition in cattle could have major benefits for reducing livestock greenhouse gas emissions and improving animal health/welfare.

Emotions, unlike mood, are short-lived reactions associated with specific events. They can be characterized by two main dimensions, their arousal (bodily activation) and valence (negative versus positive). Knowledge of the valence of emotions experienced by domestic and captive animals is crucial for assessing and improving their welfare, as it enables us to minimize the negative emotions that they might experience and to promote positive ones. Emotions can affect vocalizations directly or indirectly through the brain, lungs, larynx or vocal tract. As a result, vocal expression of emotions has been observed across species, and could serve as a non-invasive and potentially very reliable tool to assess animal emotions. In pigs (Sus scrofa), vocal expression of emotions has been relatively well studied. However, it is not known if the vocal indicators revealed in previous studies are valid across call types and contexts. To find this out, we conducted a meta-analysis of the effects of emotional valence on pig vocalizations, including calls recorded in the most common emotional situations encountered by pigs throughout their lives, from birth to slaughter. Our analyses revealed that pigs produced calls characterized by a higher center of gravity, a shorter duration, less noise (lower Wiener entropy), lower formants (measured using the formant dispersion) and LPC coefficients in positive compared to negative contexts. Overall, these vocal parameters could be very useful for developing automated methods to monitor pig welfare on-farm.

Based on the animal’s reaction to environmental challenges, consistent but different coping styles can be identified, which in turn may have consequences for health and welfare. Therefore, profound knowledge of the complex interrelationships between individual behavioral response patterns, underlying neurobiological mechanisms and immunological effects is required. The aim of this study was to examine whether pigs with different coping styles exhibit distinct behavioral, neurobiological and immune responses to stressful situations. Therefore, pigs (n = 40) were classified as proactive, reactive or intermediate animals according to a repeatedly-performed backtest, and behavioral, neuroendocrine and immune alterations were analyzed without any stress before weaning on day 28 and after a stress treatment on day 32. Our results show that the behavioral responses in an open-field/novel-object test characterized proactive pigs as more active. There were no significant differences in adrenocorticotropic hormone and cortisol concentrations between pigs with different coping characteristics. However, we found that proactive pigs displayed significantly increased plasma noradrenaline levels in response to stress, which may reflect a higher sympathetic reactivity of these animals. Furthermore, the present study revealed coping style differences in mRNA expression of mineralocorticoid, glucocorticoid, oxytocin and arginine vasopressin receptors and the immediate early gene c-fos in stress-related brain regions. While proactive pigs responded to stress with higher mRNA expression of arginine vasopressin, mineralocorticoid and glucocorticoid receptors, reactive pigs displayed higher oxytocin receptor and c-fos mRNA expression, indicating different neurobiological mechanisms of distinct coping styles in response to stressful challenges. Moreover, we also found humoral immune differences between proactive, intermediate and reactive animals. Proactive pigs had a higher total serum IgA concentration before and after stress treatment, with a significant increase in response to stress compared to reactive and intermediate pigs. In contrast, stress-induced IgM concentrations only increased in reactive and intermediate animals, suggesting that the effects of coping style on humoral immunity may differ depending on the specific function of the immunoglobulin classes. In conclusion, this multidisciplinary study expands the concept of coping style in farm animals, particularly in terms of individual stress reactivity and disease susceptibility, and thus contributes to the understanding of the biology of animal welfare.

The growing recognition of animals as individuals has broader implications for farm animal welfare research. Even under highly standardized on-farm conditions, farm animals show heterogeneous but individually consistent behavioural patterns towards various stimuli, based on how they appraise these stimuli. As a result, animal welfare is likely to be highly individual as well, and studying the proximate mechanisms underlying distinct individual behaviour patterns and appraisal will improve animal welfare research. We propose to extend the framework of affective styles to bridge the gap between existing research fields on animal personality and affective states. Affective styles refer to consistent individual differences in emotional reactivity and regulation and can be predicted by baseline cerebral lateralization. Likewise, animals with consistent left or right motor biases—a proxy measure of individual patterns in cerebral lateralization—have been shown to differ in their personality, emotional reactivity, motivational tendencies or coping styles. In this paper, we present the current knowledge of the links between laterality and stable individual traits in behaviour and affect in light of hypotheses on emotional lateralization. Within our suggested framework, we make recommendations on how to investigate affective styles in non-human animals and give practical examples. This approach has the potential to promote a science of affective styles in nonhuman animals and significantly advance research on animal welfare.

Intensive husbandry usually offers only limited opportunities for animals to perform their characteristic species–specific behavior and can lead to boredom, stress or frustration. The positive impact of structural forms of environmental enrichment on animal welfare is well investigated because it is relatively low-cost and quickly performed. In contrast, approaches that integrated cognitive enrichment into the housing of animals are hardly investigated. The present study assessed the impact of structural and cognitive enrichment on learning as well as on the behavioral and physiological responses of 34 female dwarf goats ( Capra aegagrus hircus ) using a 2 × 2 factorial design. After weaning at the age of 5 weeks, the animals were randomly allocated to four groups (8–9 goats per group). Two of the animal groups were housed under conditions of structural enrichment; the other two groups under barren housing conditions. One group, respectively, obtained drinking water at a normal water bowl, the other obtained drinking water as a reward for a correct choice at a learning device, which was integrated into the housing pen and presented automatically visual four-choice discrimination tasks. Before the first and after each of three different learning tasks, the reactions of the animals to external challenges in a combined open-field/novel-object test were recorded. An enriched environment was shown to positively affect the learning performance of the goats. Structural enrichment of the housing conditions increased the motor activity of the animals in the external test situation, whereas cognitive enrichment lead to enhanced curiosity toward and prolonged contact with the unknown object. However, there were no differences in stress levels, which were measured through salivary cortisol, between any of the groups. We conclude that the combination of structural and cognitive enrichment in particular can improve the behavioral competence of dwarf goats in challenging situations and may have beneficial effects for their welfare.

The first aim of this study was to establish a surgical procedure to implant a new telemetric device for the continuous recording of electrocardiogram (ECG) and blood pressure (BP) in freely moving pigs. A second aim was the functional assessment of cardiovascular parameters, including heart rate variability (HRV) and blood pressure variability (BPV), so that these data could be used as the basis for the objective evaluation of autonomic activity and balance in different behavioural contexts. Eleven domestic pigs (German Landrace) underwent surgery for the placement of a telemetric device. At day 15 after surgery, 512 consecutive inter-beat intervals and pressure waves were analysed using different detection methods (automatic and manually corrected) while the animals were resting or feeding, respectively. HRV and BPV were calculated. Incomplete datasets were found in four pigs due to missing ECG or BP signals. Technical and surgical issues concerning catheterisation and detachment of the negative ECG lead were continuously improved. In the remaining pigs, excellent signal quality (manually corrected data of 1%) was obtained during resting and acceptable signal quality (

a b s t r a c t The occurrence of different behavioural phenotypes in animals (regarding temperament and personality) has increasingly attracted the attention of scientists dealing with farm animal breeding, management and welfare. As part of the adaptation repertoire, coping behaviour describes how animals deal with chal- lenging situations. To detect different coping strategies (active vs. passive) in domestic pigs, Hessing et al. (1993) suggested using the backtest at an early age. However, the literature contains ambiguous results and criticism of the backtest. Thus, referring to Jensen (1995), the aim of our study was to analyse the backtest in terms of intra-situational behaviour (frequency distribution, behavioural consistency, heri- tability) in a large sample of domestic piglets (n = 3555). By using a statistical resampling analysis we wanted to verify whether the individual variation in the behaviour of the piglets in the repeated back- test indicates coping strategies or just random variation. The backtest was repeated four times between the first and fourth week of life (ages 5, 12, 19 and 26 days), and the latency, total duration and fre- quency of all struggling attempts were recorded. Our results show a continuous, unimodal distribution in the frequency parameter and an apparent bimodal distribution in the latency and duration parame- ter, that probably represents a unimodal distribution with a 'ceiling-effect'. The intra-test consistency of the behaviour (Spearman rank correlation (rS) and repeatability (R)) was moderate (rS = 0.19-0.45, p < 0.001; R = 0.25-0.39), indicating at least a certain degree of behavioural consistency. The resampling analysis revealed that the piglets did not show just random variation in behaviour. Moreover, the piglets did not display a general habituation to the repeated backtest. Based on a large pedigree, we calculated that the heritability of the behavioural parameters ranged from 0.17 to 0.43. In conclusion, the repeated backtest does not provide evidence for definitive coping strategies that are clearly separable. We instead found pronounced individual dispositions that are partly determined by genetics along a continuum from active to passive coping behaviour. This means that individuals show both behavioural consistency and flexibility in behaviour.

Vocalizations have long been recognized to encode information about an individual's emotional state and, as such, have contributed to the study of emotions in animals. However, the potential of vocalizations to also encode information about an individual's emotional reactivity has received much less attention. In this study, we aimed to test whether the vocalizations of domestic pigs contain correlates of emotional reactivity that are consistent between different contexts. We recorded vocalizations of 120 young female pigs in an experimental arena in two consecutive recording contexts, social isolation and an encounter with a familiar human. Simultaneously, we measured their heart rate and behaviour to determine their emotional reactivity in the same context (within-context). In addition, we aimed to determine the subjects' emotional reactivity in other contexts (across-context) by measuring their behaviour in four common tests of emotional reactivity, the human approach test, the open door test, the open field test and the novel object test. Using a cluster analysis, we identified four different call types. Significant inter-context correlations were found for all call types, suggesting that pig vocalizations are consistent within an individual across contexts. The call rate and the proportions of the individual call types were found to correlate significantly with indices of emotional reactivity both within and across contexts. Thereby, we found more significant correlations to indices of emotional reactivity within context (behavioural and physiological response during recording) compared to across context (behavioural response in the four emotional reactivity tests). The consistency of the vocal correlates to emotional reactivity between the different contexts depended on the call type. While we found moderate evidence that the high grunt is indicative of more active, more explorative and less fearful individuals both within as well as across contexts, the other call types provided less consistent results. Thus, it seems that some call types are better suited to provide information on a caller's emotional reactivity than others, and further research is needed to clarify the underlying influential factors.

Based on individual adaptive strategies (coping), animals may react differently to environmental challenges in terms of behavior and physiology according to their emotional perception. Emotional valence as well as arousal may be derived by measuring vagal and sympathetic tone of the autonomic nervous system (ANS). We investigated the situation-dependent autonomic response of 16 domestic pigs with either a reactive or a proactive coping style, previously selected according to the backtest which is accepted in piglets to assess escape behavior. At 11 weeks of age, the pigs were equipped with an implantable telemetric device, and heart rate (HR), blood pressure (BP) and their respective variabilities (HRV, BPV) were recorded for 1 hour daily over a time period of 10 days and analyzed in four behavioral contexts (resting, feeding, idling, handling). Additionally, the first minute of feeding and handling was used for a short-term analysis of these parameters in 10-s intervals. Data from day 1-3 (period 1) and day 8-10 (period 2) were grouped into two separate periods. Our results revealed general differences between the coping styles during feeding, resting and handling, with proactive pigs showing higher HR compared to reactive pigs. This elevated HR was based on either lower vagal (resting) or elevated sympathetic activation (feeding, handling). The short-term analysis of the autonomic activation during feeding revealed a physiological anticipation reaction in proactive pigs in period 1, whereas reactive pigs showed this reaction only in period 2. Food intake was characterized by sympathetic arousal with concurrent vagal withdrawal, which was more pronounced in proactive pigs. In contrast, neither coping style resulted in an anticipation reaction to handling. Vagal activation increased in reactive pigs during handling, while proactive pigs showed an increase in sympathetically driven arousal in period 2. Our findings confirm significant context-related differences in the general autonomic reaction of pigs with different coping styles. Additionally, the two coping styles differ in their affective appraisal over the time course of the experiment, underlining the importance of taking individual differences into account when studying affect and emotion in humans and animals.

Stress response and coping behavior in pigs are largely shaped by hypothalamic-pituitary-adrenal axis and sympatho-adrenomedullary system action. However, the dynamic interaction between amygdala and hippocampus crucially modulates the behavioral response towards significant emotional events. While this functional relationship is well documented, the molecular underpinnings still remain insufficiently understood. Our study used transcriptome profiling of porcine amygdala and hippocampus to identify molecular pathways that are differentially activated depending on the haplotype of a significantly coping behavior-associated region on pig chromosome 12 (SSC12). The pigs were classified into two groups based on the haplotype information of this QTL-region discovered in our previous genome-wide association study. Ten each of high- (HR) and low- (LR) reactive pigs (n = 20) were selected for differential gene expression analysis and weighted gene co-expression analysis with subsequent pathway analysis. Differentially expressed genes identified in the amygdala include SELL, CXCR7 and NTS, while TRAF3, PTGS2 and CFI were detected in the hippocampus indicating a role of neuroinflammation and immunological processes. Pathway analysis revealed IL-8 signaling, NF-κB signaling, glutamate and GABA metabolism, glucocorticoid receptor signaling and chemokine signaling in the amygdala and ephrin receptor signaling, as well as NF-κB signaling in the hippocampus. We discovered candidate genes in regions detected by genome-wide association study including ARRB2, ADRBK2, THRB, NEK7 and ACVR2B, which relate to dopaminergic and other monoaminergic neurotransmitter systems, neuroimmunomodulation, neuroinflammation and GABA-ergic neurotransmission. These findings provide insights into the molecular underpinning of divergent coping behavior and associated haplotypes in limbic forebrain system in pig.

Studies on consequences of affect on cognitive processing (cognitive bias) seem to provide proxy measures of the valence (positive/negative) of affective states. This article presents a pilot study testing a design for studies of judgment bias we adapted to the specific needs and abilities of domestic pigs. We used a spatial judgment paradigm, in which subjects learned to discriminate a food rewarded from an unrewarded position of a goal box during a training period, and then were tested for their responses to 3 equidistant intermediate probe positions during a testing period. After the training period, half of the subjects were repeatedly isolated from their social group to manipulate their affective state. Subjects learned the required discrimination task (positive vs. negative stimulus) and showed consistent differences in approach latencies toward and exploration of stimuli of different valence. Hence, the subjects' expectations could be inferred from their behavior. However, repeated social isolation had no effect on judgment of ambiguous stimuli and on both basal and test-related cortisol levels. In conclusion, the spatial judgment approach seems to provide a useful tool to detect and discriminate diverse affective states in domestic pigs based on their responses to graded ambiguous stimuli.

Cognitive enrichment, a special form of environmental enrichment, addresses the cognitive abilities of animals in captivity. Through cognitive interaction with the environment, the animals regain a certain control over their environment, and essential resources, such as food or water, act as a reward for successful coping. It is assumed that this process has important implications for animal welfare, especially in the intensive housing systems of farm animals. This study investigates the effects of cognitive enrichment on welfare-relevant behaviour (agonistic interactions and behavioural reactivity in a repeated open-field test) and autonomic control (heart rate variability during feeding, resting and in a repeated open-field test) in domestic pigs. A total of forty-eight pigs, Sus scrofa, were housed in groups of four. In six replicates, an experimental group was compared with a conventionally fed control group. The pigs in the experimental group were confronted with a cognitive challenge that was integrated into their familiar housing environment. Pigs were rewarded with food after they successfully mastered the discrimination of an individual acoustical signal followed by an operant task. The pigs in both groups reacted with sympathetic arousal to feeding announcement (increased heart rate (HR)). During feeding, the experimental pigs' HR decreased, and heart rate variability (HRV) increased, while the control pigs' HR stayed highly elevated and HRV decreased. These results are supported by a considerably larger number of agonistic interactions during feeding in the control group. During resting, the basal HRV of the experimental pigs increased (during operant conditioning) compared to the control. In the repeated open-field test, the experimental pigs displayed less locomotion and elimination as well as more contact with the wall and an unknown object compared to the control group. We conclude that cognitive enrichment leads to relaxed feeding and evokes longer lasting positive emotions. Moreover, the pigs displayed more explorative and less fearful behaviour in stressful situations. These findings support the use of cognitive enrichment to improve animal welfare.

The study and protection of animal welfare are based on the assumption that animals are sentient beings, capable of experiencing emotions. Still, our understanding of animal emotions is limited. In this review we focus on the potential of cerebral-lateralization research to provide new insights into animal emotional processing. Thereby, our aims were, first, to find a universal lateralization pattern in emotional processing across vertebrates and, second, to discuss how knowledge of emotional-lateralization patterns can be used in science and practice to contribute to improve farm-animal welfare. A literature review suggests evidence of lateralized functioning during emotional contexts across the vertebrate classes, from early vertebrates such as fish and amphibians to non-human primates. With the possible exception of fish, all vertebrate classes seem to show a similar lateralization pattern for emotional processing, with a right-hemisphere dominance for processing rather negatively connotated emotions, such as fear and aggression, and a left-hemisphere dominance for processing positively connotated emotions, such as those elicited by a food reward. Thus, both hemispheres are involved in emotional processing and hemispheric dominance may be used as an indicator of emotional valence (negative-positive). Although only a few domestic animal species (e.g. chicken, sheep, dog and horse) have been extensively studied with regard to emotional lateralization, evidence gathered so far suggests that the right-hemisphere dominance for fear and aggression and left-hemisphere dominance in responses to food rewards also applies to these species. Such patterns could be exploited in animal welfare studies to gain insight into how an animal experiences a potentially emotional situation and to improve farm-animal management. Further research should focus on rarely-studied species and on rarely-studied emotional contexts, such as sex and positive social situations, to improve our understanding of animal emotional lateralization.

Exposure to psychosocial stress can have a profound impact on immune reactivity and health mediated by hypothalamic–pituitaryadrenal (HPA) axis activation. However, current knowledge regarding the mechanisms involved in cross-sensitization between stress and the immune system is limited. Here, we investigated the effects of a single social isolation followed by repeated oral Escherichia coli (E. coli) applications on cortisol, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), haptoglobin and C-reactive protein (CRP) concentrations in the blood; on clinical signs of disease; and on mRNA expression of the glucocorticoid receptor (GR), mineralocorticoid receptor (MR), 11β-hydroxysteroid dehydrogenase 1 and 2 (11β-HSD1 and 11β-HSD2), TNF-α and IL-6 in the hypothalamus, prefrontal cortex (PFC) and spleen of 7-, 21- and 35-day-old piglets. Additionally, the protein levels of splenic TNF-α and IL-6 were analyzed. Non-isolated, E. coli-challenged piglets served as a control. Social isolation for 4 h induced a rise in the plasma cortisol concentrations immediately after social treatment and after repeated E. coli applications in isolated compared to non-isolated piglets. The circulating TNF-α concentration was not affected by social treatment. Furthermore, previously isolated piglets showed a higher frequency of signs of disease in response to E. coli challenge than non-isolated piglets, while the haptoglobin and CRP concentrations did not significantly differ between social treatments. In the brain, 11β-HSD1, 11β-HSD2 and IL-6 mRNA expression in the hypothalamus and GR, and 11β-HSD1 and 11β-HSD2 mRNA expression in the PFC were higher in isolated, E. coli-challenged piglets than in the corresponding controls. Moreover, isolated piglets also displayed higher MR, 11β-HSD1 and IL-6 mRNA expression levels and TNF-α concentrations in the spleen. The stress-induced alterations in the hypothalamus and spleen were particularly pronounced in younger piglets. The present findings may contribute to a better understanding of the complex interplay between early psychological stress and an increased risk of disease and might also have implications on aspects of the health and welfare of farm animals and humans.

Abnormal behaviour is a potential indicator of pain, suffering and injury in captive animals. Especially stereotypies, i. e. repetitive invariant behavioural patterns without obvious function or goal, can be observed as a consequence of inadequate housing conditions. Hence, they are often considered indicators of impaired welfare. In context of the ongoing scientific debate on captive animal welfare, the number of publications on stereotypies has increased, most notably in veterinary and farm animal research. Based on biological principles and definitions, we present several examples of stereotypic behaviour in (mainly) farm animals, and discuss approaches of preventing or reducing them. The occurrence of abnormal behaviour is often, but not necessarily, associated with the fact that modern housing and management precludes various evolutionary emerged highly motivated behaviours, or poses challenges the animals are unable to cope with adequately. Numerous studies show that stereotypies can be indicative of (current or past) suffering and impaired welfare. They can be avoided or at least reduced by increasing the biological relevance of the housing environments through environmental enrichment which stimulates species-specific behaviour.

There is growing evidence that social support given by a conspecific attenuates stress responses of a socially deprived animal. We hypothesized that the presence of a familiar social partner modulates the effectiveness of social buffering as assessed by an altered glucocorticoid sensitivity of immune cells. The current study investigated the effects of a 4-h social deprivation procedure on stress hormone responses and immune cell functions in 7-, 21- and 35-day-old piglets (52 males and 56 females). Within each of the three age categories, nine piglets were deprived of their mother and littermates either alone or with a familiar or unfamiliar age-matched piglet. Compared to non-deprived controls, piglets that were alone displayed significant increases in plasma adrenocorticotropic hormone and cortisol concentrations, and all socially deprived piglets showed a greater in vitro proliferative response of peripheral blood mononuclear cells (PBMCs) to lipopolysaccharide (LPS)-stimulation than controls. Concanavalin A (ConA)-induced in vitro proliferation was not affected by social treatment. Additionally, both the ConA- and LPS-stimulated PBMCs from piglets that experienced any of the deprivation treatments were more resistant to the inhibitory effects of cortisol than PBMCs from the controls in each of the three age categories. Irrespective of the mitogen used, the presence of an age-matched conspecific during deprivation attenuated the dose-dependent cortisol resistance. Here, familiarity between the piglets clearly improved the effectiveness of social support in an age-dependent manner. Collectively, our findings emphasize the benefits of social partners regarding stress coping abilities, with positive implications for animal welfare and health.

International audience; The aim of our study was to characterize the immediate phenotypic and adaptive regulatory responses of fetuses to different in utero conditions reflecting inadequate maternal protein supply during gestation. The gilts fed high- (250% above control) or low- (50% under control) protein diets isoenergetically adjusted at the expense of carbohydrates from the day of insemination until the fetuses were collected at day 64 or 94 of gestation. We analyzed body composition, histomorphology, biochemistry, and messenger RNA (mRNA) expression of fetal skeletal muscle. Both diets had only marginal effects on body composition and muscular cellularity of fetuses including an unchanged total number of myofibers. However, mRNA expression of myogenic regulatory factors (MYOG, MRF4, P ≤ 0.1), IGF system (IGF1, IGF1R, P ≤ 0.05) and myostatin antagonist FST (P = 0.6, in males only) was reduced in the fetal muscle exposed to a maternal low-protein diet. As a result of excess protein, MYOD, MYOG, IGF1R, and IGFBP5 mRNA expression (P ≤ 0.05) was upregulated in fetal muscle. Differences in muscular mRNA expression indicate in utero regulatory adaptive responses to maternal diet. Modulation of gene expression immediately contributes to the maintenance of an appropriate fetal phenotype that would be similar to that observed in the control fetuses. Moreover, we suggest that the modified gene expression in fetal skeletal muscle can be viewed as the origin of developmental muscular plasticity involved in the concept of fetal programming.

The aim of the present study was to estimate heritabilities for different agonistic behavioural traits after mixing female pigs of three age classes and to compare the agonistic behaviour between these age groups. The behavioural patterns were observed over a 48-h period, directly after weaning (PIG-28; n =884), 40 day later (growing pigs, PIG-68; n =351) and immediately after mixing gilts (GILTS; n =389) with an average age of about 242 day. Agonistic interactions were observed by noting the time of the start and finish of the interaction, the identity of the aggressor and receiver and the winner or loser of a fight. Starting from this, the frequency and the time involved were calculated for ten agonistic behavioural traits. Intermediate heritabilities were estimated for growing pigs, with the highest heritability for the number of won fights ( h 2 =0.37). In comparison, the heritabilities for weaned piglets were at a lower level with the highest heritability for the duration spent in initiated fights ( h 2 =0.20). Concerning gilts, moderate heritabilities were only found for the number of received aggressions ( h 2 =0.42), the time spent in received aggressions ( h 2 =0.15), the number of lost fights ( h 2 =0.13) and the time spent in lost fights ( h 2 =0.09). Within all three age groups, the correlations between the numbers of initiated and won fights were stronger than the correlations between the numbers of initiated and lost fights, indicating that pigs which initiated most of their fights also won the majority of their fights. Moderate correlations were found between the behavioural traits of growing pigs and gilts, but the number of relationships between the weaned piglets and older age groups was low. In conclusion, the results indicate that more aggressive growing pigs tend to also become more aggressive gilts. Additionally, the agonistic behaviour of weaned piglets cannot be compared with that of other age groups since the agonistic behaviour of weaned piglets is probably related to playfulness while in older pigs it is related to the establishment of dominance hierarchies.

The aim of the present study was to analyse whether a lesion score approach could be used as an indicator for agonistic behaviour in pigs. Behavioural patterns were observed directly after weaning (PIG-28, n=827), 40 days later (growing pigs, PIG-68, n=292) and immediately after mixing gilts (GILTS, n=344), over a 48 h period. For the front, middle and rear part of the body the extent of skin injuries was assessed with a lesion score (LS). The LS ranked from 0 (no wounds) to 4 (many, deep wounds) and was determined at the beginning (LSstart) and at the end (LSend) of the observation period. In all groups, the front body third was mostly stressed by fighting interactions. The highest correlations were found between the front LS and the overall fight time, with r=0.50 (PIG-28), r=0.52 (PIG-68) and r=0.48 (GILTS). The LS for the front area did not increase for 26 % (PIG-28), 39 % (PIG-68) and 40 % (GILTS) of the animals. According to this, the applied LS approach only reflected the agonistic behaviour of pigs to a certain extent.

The aim of the present study was to assess the effects of vaccination against boar taint on testosterone levels, body weight and behaviour in male fattening pigs when compared with boars and barrows. The study was carried out in two replicates over time. Pigs were allocated to fattening pens according to treatment group (immunised males (IM), castrated males (CM), entire males (EM)) with 10 and 13 pigs per pen in batches one and two, respectively. IM pigs were vaccinated twice with Improvac™ according to manufacturer's instructions (first injection was given on the day of entry to the fattening unit, second injection was performed when pigs had an average weight of 76.6 kg and 80.4 kg in the two replicates over time, respectively). During fattening, pigs were videotaped twice (test periods one and two) for a consecutive period of 96 h during each test period and blood samples were taken. Live weight measurements were conducted on a weekly basis. Before second vaccination was given (test period one), IM pigs had serum testosterone levels comparable to those of entire boars. Two weeks after second Improvac™-injection (test period two) testosterone levels of IM pigs decreased significantly ( p p p