The Concept of Stress and Its Relevance for Animal Behavior

Detection of arousal and valence from facial expressions and physiological responses evoked by different types of stressors

Automatically detecting mental state such as stress from video images of the face could support evaluating stress responses in applicants for high risk jobs or contribute to timely stress detection in challenging operational settings (e.g., aircrew, command center operators). Challenges in automatically estimating mental state include the generalization of models across contexts and across participants. We here aim to create robust models by training them using data from different contexts and including physiological features. Fifty-one participants were exposed to different types of stressors (cognitive, social evaluative and startle) and baseline variants of the stressors. Video, electrocardiogram (ECG), electrodermal activity (EDA) and self-reports (arousal and valence) were recorded. Logistic regression models aimed to classify between high and low arousal and valence across participants, where "high" and "low" were defined relative to the center of the rating scale. Accuracy scores of different models were evaluated: models trained and tested within a specific context (either a baseline or stressor variant of a task), intermediate context (baseline and stressor variant of a task), or general context (all conditions together). Furthermore, for these different model variants, only the video data was included, only the physiological data, or both video and physiological data. We found that all (video, physiological and video-physio) models could successfully distinguish between high- and low-rated arousal and valence, though performance tended to be better for (1) arousal than valence, (2) specific context than intermediate and general contexts, (3) video-physio data than video or physiological data alone. Automatic feature selection resulted in inclusion of 3-20 features, where the models based on video-physio data usually included features from video, ECG and EDA. Still, performance of video-only models approached the performance of video-physio models. Arousal and valence ratings by three experienced human observers scores based on part of the video data did not match with self-reports. In sum, we showed that it is possible to automatically monitor arousal and valence even in relatively general contexts and better than humans can (in the given circumstances), and that non-contact video images of faces capture an important part of the information, which has practical advantages.

Human social buffer in goats and dogs

The primary goal of this study was to explore the social buffering effect that humans offer to goats and dogs with limited exposure to human socialization, particularly in situations involving interactions with unfamiliar humans. A total of 13 dogs and 14 goats were selected for the study, all of which had limited prior socialization with humans. Each animal was placed in a testing room with unfamiliar humans for 15 min. Three experimenters aimed to establish a comfortable environment, encouraging social interaction by offering food to the animals and assessing the animals' willingness to accept food and their response to being approached and petted. If both conditions were satisfied, the animals were classified as "social". If one or none of the conditions were met, the animals were classified as "not social". Cortisol levels were measured by collecting blood samples before and after the test. Non-parametric tests together with a GzLM showed that the effect of human social buffering in goats was different in comparison to dogs: goats exhibited higher cortisol levels after the test, while dogs did not show a significant change. Further analysis demonstrated that "social" goats had a lower likelihood of experiencing significant changes in cortisol levels than dogs. Thus, once human interactions are accepted, both species could benefit from social buffering. In summary, this study enhances our understanding of how dogs and goats respond to social interactions with humans in the social buffering effect.

Age-specific effects of density and weather on body condition and birth rates in a large herbivore, the Przewalski's horse

Reproduction in young females can show a particularly sensitive response to environmental challenges, although empirical support from individual-based long-term studies is scarce. Based on a 20-year data set from a free-roaming Przewalski's horse population (Equus ferus przewalskii), we studied effects of large-herbivore density (horses + cattle) and weather conditions experienced during different life stages on females' annual birth rates. Foaling probability was very low in 2-year-olds, reaching maximum values in 5 to 10-year-olds, followed by a decrease in older females indicating reproductive senescence. Mother's previous reproductive investment affected her current reproduction; young and old mothers (as opposed to middle-aged ones), which had nursed a foal for at least 60 days during the previous year, reproduced with a lower probability. Foaling probability and body condition of young females were lower when large-herbivore density was high. Reproduction was also influenced by interactive weather effects during different life stages. Low late-summer precipitation during the females' year of birth was associated with a pronounced decrease in foaling probability in response to harsh late-winter temperatures prior to the mating season. In turn, increased amounts of late-summer rain during this early age together with more late-summer rain during the females' current pregnancy led to an increased reproductive probability in 2-3-year-olds. These results were corroborated by the ameliorating effects of late-summer rain on body condition in such females. In conclusion, our findings highlight the interactive importance of weather conditions experienced during early life, and of density and weather during current pregnancy on foaling probability, particularly in young females.

Non-invasive, real-time stress measurement: Vocalization compared with thermal imaging in kittens of the domestic cat in response to social separation

Finding tools to assess the stress response which can be easily applied, are non-invasive, reliable and measured in real time is still a relevant topic in many areas of biology. Vocal characteristics and temperature of certain body areas have been suggested to reflect HPA axis and ANS activation. We hypothesized that changes in vocalizations and peripheral body temperature will show the magnitude of the stress response, and that the change in these will covary. Our aim was to measure the change in vocal characteristics and eye and nasal temperature of kittens (n = 43 from nine litters of seven mixed-breed mothers) during a potentially stressful event and to test how these correlated. We found change in several vocal and thermal parameters during a short social separation. Our findings indicate that arousal due to ANS activation in kittens of the domestic cat resulted in an increasing number of vocalisations of longer duration and higher intensity, and in lower and a wider range in fundamental frequency. Calls also became less tonal with more jitter. Change in temperature was generally negative in the lacrimal caruncle as well as in the rhinarium, but with great variance across individuals. Change in eye temperature positively correlated with the intensity of the calls and the change in nose temperature positively correlated with the change in call length. The results suggest the continued difficulty in interpreting both physiological and behavioural data to assess an individual´s stress response.

Genomic Selection for Dairy Cattle Behaviour Considering Novel Traits in a Changing Technical Production Environment

Cow behaviour is a major factor influencing dairy herd profitability and is an indicator of animal welfare and disease. Behaviour is a complex network of behavioural patterns in response to environmental and social stimuli and human handling. Advances in agricultural technology have led to changes in dairy cow husbandry systems worldwide. Increasing herd sizes, less time availability to take care of the animals and modern technology such as automatic milking systems (AMSs) imply limited human-cow interactions. On the other hand, cow behaviour responses to the technical environment (cow-AMS interactions) simultaneously improve production efficiency and welfare and contribute to simplified "cow handling" and reduced labour time. Automatic milking systems generate objective behaviour traits linked to workability, milkability and health, which can be implemented into genomic selection tools. However, there is insufficient understanding of the genetic mechanisms influencing cow learning and social behaviour, in turn affecting herd management, productivity and welfare. Moreover, physiological and molecular biomarkers such as heart rate, neurotransmitters and hormones might be useful indicators and predictors of cow behaviour. This review gives an overview of published behaviour studies in dairy cows in the context of genetics and genomics and discusses possibilities for breeding approaches to achieve desired behaviour in a technical production environment.

Season-dependent impact of forage quality on stress in alpine chamois

Chronically heightened stress levels in wildlife species may have detrimental effects on individual life history traits, for example, through the increased likelihood of disease, parasitic infections, and overall reduced fitness. Understanding the drivers of stress may thus have great potential for informing wildlife conservation. Although the role of climate and individual status is well studied in stress ecology, the impact of related stressors such as dietary quality is of increasing interest to wildlife research and conservation. In this study, fecal cortisol metabolites (FCMs) in Alpine chamois Rupicapra r. rupicapra used as bioindicators of stress, and their relationship with forage quality-measured as the percentage of fecal crude protein (CP)-were investigated. Data collection took place in 2011 and 2012 in the Gran Paradiso National Park (Western Italian Alps), on 22 individually marked adult males. The relationship between FCMs and CPs was analyzed through linear models and separated between winter and summer months, accounting for the effect of potentially confounding exogenous and endogenous variables. After AICc-based model selection, we found that forage quality was negatively related to FCM levels in Alpine chamois during the summer months, meaning that higher quality forage was associated with the decreased expression of stress hormones. However, during the winter months, we did not find a significant relationship, potentially as a result of forage quality being ubiquitously poor. Although the mechanisms through which dietary variations impact FCM concentrations in wildlife populations are largely unknown, the occurrence of significant relationships between forage quality and stress levels supports potentially important implications for the long-term effect of climatic changes on the fitness of wildlife populations.

Sex-dependent worsening of NMDA-induced responses, anxiety, hypercortisolemia, and organometry of early peripheral immunoendocrine impairment in adult 3xTg-AD mice and their long-lasting ontogenic modulation by neonatal handling

The neuroimmunomodulation hypothesis for Alzheimer's disease (AD) postulates that alterations in the innate immune system triggered by damage signals result in adverse effects on neuronal functions. The peripheral immune system and neuroimmunoendocrine communication are also impaired. Here we provide further evidence using a longitudinal design that also studied the long-lasting effects of an early life sensorial intervention (neonatal handling, from postnatal day 1-21) in 6-month-old (early stages of the disease) male and female 3xTg-AD mice compared to age- and sex-matched non-transgenic (NTg) mice with normal aging. The behavioral patterns elicited by the direct exposure to an open field, and the motor depression response evoked by NMDA (25 mg/kg, i.p) were found correlated to the organometry of peripheral immune-endocrine organs (thymus involution, splenomegaly, and adrenal glands' hypertrophy) and increased corticosterone levels, suggesting their potential value for diagnostic and biomonitoring.The NMDA-induced immediate and depressant motor activity and endocrine (corticosterone) responses were sensitive to sex and AD-genotype, suggesting worse endogenous susceptibility/neuroprotective response to glutamatergic excitotoxicity in males and in the AD-genotype. 3xTg-AD females showed a reduced immediate response, whereas the NTg showed higher responsiveness to subsequent NMDA-induced depressant effect than their male counterparts. The long-lasting ontogenic modulation by handling was shown as a potentiation of NMDA-depressant effect in NTg males and females, while sex × treatment effects were found in 3xTg-AD mice. Finally, NMDA-induced corticosterone showed sex, genotype and interaction effects with sexual dimorphism enhanced in the AD-genotype, suggesting different endogenous vulnerability/neuroprotective capacities and modulation of the neuroimmunoendocrine system.

Hierarchy Establishment in Growing Finishing Pigs: Impacts on Behavior, Growth Performance, and Physiological Parameters

In recent years, an increased number of studies have dealt with the analysis of social dominance related to animal behavior, physiology, and performance. This study aimed to investigate whether hierarchical ranking affects the coping style, non-social behavior during open field and novel object tests, performance, and physiological parameters of pigs. A total of 48 growing pigs (24 barrows and 24 females) were mixed three times during the growing-finishing period. The social and non-social behaviors of pigs were directly noted, and three behavioral tests were performed during the experimental period. Performance and physiological parameters were also recorded. Statistical analysis considered hierarchical classification (dominant vs. intermediary vs. subordinate) and p-values ≤ 0.05 were considered significant. After three regroupings, the pigs in different hierarchical classifications showed no change in hair cortisol values and open-field and novel object tests. Mean corpuscular hemoglobin concentration and leukocyte values increased in intermediary pigs, and the lowest counts were found in pigs classified as dominants. Furthermore, dominant pigs visited the feeder more but spent shorter time there compared to subordinate and intermediary pigs. Our results suggest that hierarchical classification influenced feeding behavior and physiological parameters without affecting cortisol values and growth performance, demonstrating a possible compensation skill.

Human-directed attachment behavior in wolves suggests standing ancestral variation for human-dog attachment bonds

Domesticated animals are generally assumed to display increased sociability toward humans compared to their wild ancestors. Dogs (Canis familiaris) have a remarkable ability to form social relationships with humans, including lasting attachment, a bond based on emotional dependency. Since it has been specifically suggested that the ability to form attachment with humans evolved post-domestication in dogs, attempts to quantify attachment behavior in wolves (Canis lupus) have subsequently been performed. However, while these rare wolf studies do highlight the potential for wolves to express human-directed attachment, the varied methods used and the contrasting results emphasize the need for further, standardized testing of wolves. Here, we used the standardized Strange Situation Test to investigate attachment behavior expressed in wolves and dogs hand-raised and socialized under standardized and identical conditions up until the age of testing. We found that 23-week-old wolves and dogs equally discriminated between a stranger and a familiar person, and expressed similar attachment behaviors toward a familiar person. Additionally, wolves, but not dogs, expressed significantly elevated stress-related behavior during the test, but this stress response was buffered by the presence of a familiar person. Together, our results suggest that wolves can show attachment behaviors toward humans comparable to those of dogs. Importantly, our findings demonstrate that the ability to form attachment with humans exists in relatives of the wild ancestor of dogs, thereby refuting claims that this phenotype evolved after dog domestication was initiated.

Expanding the frame around social dynamics and glucocorticoids: From hierarchies within the nest to competitive interactions among species

The effect of the social environment on individual state or condition has largely focused on glucocorticoid levels (GCs). As metabolic hormones whose production can be influenced by nutritional, physical, or psychosocial stressors, GCs are a valuable (though singular) measure that may reflect the degree of "stress" experienced by an individual. Most work to date has focused on how social rank influences GCs in group-living species or how predation risk influences GCs in prey. This work has been revealing, but a more comprehensive assessment of the social environment is needed to fully understand how different features of the social environment influence GCs in both group living and non-group living species and across life history stages. Just as there can be intense within-group competition among adult conspecifics, it bears appreciating there can also be competition among siblings from the same brood, among adult conspecifics that do not live in groups, or among heterospecifics. In these situations, dominance hierarchies typically emerge, albeit, do dominants or subordinate individuals or species have higher GCs? We examine the degree of support for hypotheses derived from group-living species about whether differential GCs between dominants and subordinates reflect the "stress of subordination" or "costs of dominance" in these other social contexts. By doing so, we aim to test the generality of these two hypotheses and propose new research directions to broaden the lens that focuses on social hierarchies and GCs.

Aspects of social behaviour and reproduction in the wild rabbit – Implications for rabbit breeding?

Further knowledge on aspects of social behaviour in the wild rabbit (Oryctolagus cuniculus), including the link to reproduction, could possibly point to new ways to improve housing and breeding conditions in rabbit farming. In this review, I present some results of our long-term study on a 2-hectare field enclosure population of wild rabbits (University of Bayreuth, Germany), exploring group-level and individual-level differences in agonistic behaviour of females and their potential associations with reproductive traits, including offspring survival. The frequency of agonistic behaviour in which females were involved, increased with increasing group size, and was lower in groups with a more heterogeneous age structure. At the individual level, reproducing females were involved in more agonistic interactions when groupmates gave birth and thus built their burrows and nests at around the same time, and higher-ranking mothers were particularly aggressive when other females approached close to their nursery burrows. Associations between females’ social environment and reproduction were evident, as the numbers of litters and offspring per female were lower at higher female densities, high-ranking females produced more offspring and had a lower offspring mortality than low-ranking ones, and cases of infanticide were lower in more stable groups, which we quantified by the more heterogeneous age structure of the females’ rank hierarchy in such groups. Furthermore, perinatal offspring mortality was increased in females with a delayed burrow and nest building activity, i.e. does that dug their nursery burrow and built their nest only during the last 24 h pre-partum, possibly driven by the more unfavourable social environment experienced by such females. Most importantly, our studies highlight the importance of the presence of litter siblings in improving an individual’s social environment, which resulted in an earlier onset of breeding in such females. Higher levels of positive social interactions with litter siblings were also associated with lower stress hormone (corticosterone) levels and with a better health status in terms of lower loads with an intestinal nematode. These findings on ameliorating effects of litter sibling presence in growing rabbits as well as in reproducing females may be a promising starting point worth further exploration in the context of group housing of domestic rabbits.

Handlers' Representations on Therapy Dogs' Welfare

While research on the benefits of animal-assisted interventions is beginning to build a significant body of work, studies on the well-being of therapy dogs are still in their infancy. Since handlers are the people responsible for their therapy dog's welfare, we interviewed 111 French handlers through an online questionnaire. Our results underlined that (i) therapy dogs' welfare is multidimensional when physical and psychological welfare, a balance between work and dog life and the settings and interactions of sessions are all taken into consideration. (ii) The response of our handlers emphasized that considering therapy dog welfare is important for the quality and safety of AAI. (iii) Three categories of risks factors were highlighted: the spatio-temporal framework (planning and environment), the interactions with beneficiaries and the handler themselves. It is particularly important that handlers talk about the negative impact of interactions with beneficiaries since they are at the heart of AAI, however there are few studies focusing on interactions as a stressor for dogs in this practice. Moreover, since there is a potential for positive bias in the handlers' representations, it is important that they be trained to identify and manage the stress in their dogs. Future research is particularly needed on the impact of interactions during sessions on therapy dog welfare.

Neurobiological Bases of Alcohol Consumption After Social Stress

The urge to seek and consume excessive alcohol is intensified by prior experiences with social stress, and this cascade can be modeled under systematically controlled laboratory conditions in rodents and non-human primates. Adaptive coping with intermittent episodes of social defeat stress often transitions to maladaptive responses to traumatic continuous stress, and alcohol consumption may become part of coping responses. At the circuit level, the neural pathways subserving stress coping intersect with those for alcohol consumption. Increasingly discrete regions and connections within the prefrontal cortex, the ventral and dorsal striatum, thalamic and hypothalamic nuclei, tegmental areas as well as brain stem structures begin to be identified as critical for reacting to and coping with social stress while seeking and consuming alcohol. Several candidate molecules that modulate signals within these neural connections have been targeted in order to reduce excessive drinking and relapse. In spite of some early clinical failures, neuropeptides such as CRF, opioids, or oxytocin continue to be examined for their role in attenuating stress-escalated drinking. Recent work has focused on neural sites of action for peptides and steroids, most likely in neuroinflammatory processes as a result of interactive effects of episodic social stress and excessive alcohol seeking and drinking.

Of Whales and Genes: Unraveling the Physiological Response to Stressors in Belugas (Delphinapterus leucas) at the Molecular Level

Marine mammals, now more than ever, are exposed to environmental and anthropogenic stressors. A better understanding of stress physiology in marine mammals is warranted in order to assist in conservation efforts. This study screened gene expression profiles (cytokines, stress-response markers) in blood samples collected opportunistically under controlled conditions from aquarium belugas during transport and introduction to a novel environment (T/NEnv), participation in out-of-water examinations (OWE) and from wild belugas during live capture–release health assessments (WLCR). Quantitative-PCR was used to measure gene expression involved in physiological and immune responses at different time scales. Linear mixed models with repeated measures and pairwise comparisons were used for analysis. Overall, a generalized down-regulation of relative gene expression when compared to samples collected under behavioral control from aquarium whales or to pre-assessment samples of wild whales was observed, with genes IFNγ, IL2, TGFβ and Nr3c1 displaying the largest significant (p < 0.05) changes. Significant (p < 0.05) negative associations of inflammatory gene expression with norepinephrine suggest inhibitory effects of catecholamines on the inflammatory response. Overall, this study contributes to our understanding of the physiological response to stressors at the molecular level in belugas, and the genes suggested here can further be utilized as additional tools in beluga health assessments and monitoring.

Heart rate as a measure of emotional arousal in evolutionary biology

How individuals interact with their environment and respond to changes is a key area of research in evolutionary biology. A physiological parameter that provides an instant proxy for the activation of the automatic nervous system, and can be measured relatively easily, is modulation of heart rate. Over the past four decades, heart rate has been used to assess emotional arousal in non-human animals in a variety of contexts, including social behaviour, animal cognition, animal welfare and animal personality. In this review, I summarize how measuring heart rate has provided new insights into how social animals cope with challenges in their environment. I assess the advantages and limitations of different technologies used to measure heart rate in this context, including wearable heart rate belts and implantable transmitters, and provide an overview of prospective research avenues using established and new technologies, with a special focus on implications for applied research on animal welfare. This article is part of the theme issue 'Measuring physiology in free-living animals (Part II)'.

Glucocorticoid-Mediated Changes in Male Green Treefrog Vocalizations Alter Attractiveness to Females

Adrenal glucocorticoids (GCs) are increasingly recognized as important modulators of male courtship signals, suggesting that circulating levels of these steroids can play a central role in sexual selection. However, few studies have examined whether GC-mediated effects on male sexual signals actually impact mate choice by females. Here, we examine how corticosterone (CORT)-mediated changes in the vocalizations of male green treefrogs, Dryophytes cinereus, influence attractiveness to females. In this species, agonistic acoustic signaling between rival males competing for mates increases circulating CORT levels in contest losers. Acute elevations in CORT, in turn, decrease the duration of male advertisement calls and increase the latency between successive calls, resulting in a net reduction in vocal effort (the amount of signaling per unit time) that occurs independently of changes in circulating androgens. Based on known preferences for acoustic features in D. cinereus, and other anuran species, the direction of CORT-mediated effects on temporal call characteristics is expected to compromise attractiveness to females, but whether they are of sufficient magnitude to impact female mate choice decisions is unclear. To examine whether CORT-mediated effects on male advertisement calls reduce attractiveness to females, we broadcast vocalizations in dual speaker playback experiments approximating the mean and 1 SD above and below the mean call duration and vocal effort values (the two primary vocal features impacted by elevated CORT) of males with low and high CORT levels. Results revealed strong preferences by females for the calls characteristic of males with low CORT in tests using the approximate mean and 1 SD above the mean call duration and vocal effort values, but females did not show a preference for calls of males with low CORT in trials using call values approximating 1 SD below the mean. Overall, females preferred males with signal traits predictive of low CORT, however this effect was nonlinear with attenuated preferences when signal alternatives differed only marginally indicating a possible thresholding effect. Specifically, females appeared to discriminate between males with low versus high CORT based primarily on differences in call rates associated with CORT-mediated changes in call duration and vocal effort. Our results highlight that changes in circulating CORT during male-male vocal interactions can decrease attractiveness to females, suggesting that circulating levels of CORT can play a critical role in both intra- and intersexual selection.

Individuality meets plasticity: Endocrine phenotypes across male dominance rank acquisition in guinea pigs living in a complex social environment

The time of dominance rank acquisition is a crucial phase in male life history that often affects reproductive success and hence fitness. Hormones such as testosterone and glucocorticoids can influence as well as be affected by this process. At the same time, hormone concentrations can show large individual variation. The extent to which such variation is repeatable, particularly in dynamic social settings, is a question of current interest. The aim of the present study was therefore to investigate how dominance rank and individual differences contribute to variance in hormone concentrations during male rank acquisition in a complex social environment. For this purpose, dominance rank as well as baseline testosterone, baseline cortisol, and cortisol responsiveness after exposure to a novel environment were determined in colony-housed guinea pig males from late adolescence through adulthood. Hormone-dominance relationships and repeatability of hormone measures beyond their relation to rank were assessed. There was a significant positive relationship between baseline testosterone and rank, but this link became weaker with increasing age. Baseline cortisol or cortisol responsiveness, in contrast, were not significantly related to dominance. Notably, all three endocrine parameters were significantly repeatable independent of dominance rank from late adolescence through adulthood. Baseline testosterone and cortisol responsiveness showed a significantly higher repeatability than baseline cortisol. This suggests that testosterone titres and cortisol responsiveness represent stable individual attributes even under complex social conditions.

Omics Insights into Animal Resilience and Stress Factors

Resilience is conceived as a dynamic developmental process involving the achievement of positive adaptation within the context of significant adversity. Resilience is not a unique ability but rather a set of capacities of a system put in place to absorb a disturbance and to reorganize while trying to retain the same function, structure, and identity. This review describes the characteristics and the molecular mechanisms of resilience to understand the core elements of resilience and its indicators. The objectives of this review are: (1) to define some of the leading environmental stressors and clarify the mechanism of vulnerability or resilience outcomes; (2) to clarify some of the prominent epigenetic modulations mediating resilience or vulnerability as a stress response; (3) to highlight the neural mechanisms related to stress resilience since the central nervous system is a highly dynamic structure characterized by an everlasting plasticity feature, which therefore has the opportunity to modify resilience. The review aims to introduce the reader to the concept of resilience seen as an ability acquired in life and not only inherited from birth.

Within-litter covariance of allele-specific MHC heterozygosity, coccidian endoparasite load and growth is modulated by sibling differences in starting mass

Although littermates in altricial mammals usually experience highly similar environmental conditions during early life, considerable differences in growth and health can emerge among them. In a study on subadults of a European rabbit (Oryctolagus cuniculus) population with low MHC polymorphism, we tested whether litter-sibling differences in endoparasitic coccidia load and body mass at the end of the vegetation period were associated with within-litter differences in starting body mass (measured around 2 weeks prior to weaning) and in immune-genetic (MHC class II DRB) constitution. We hypothesized that siblings with a lighter starting mass might be more susceptible to endoparasite infections and thus, negative effects of a more unfavourable MHC constitution might be particularly pronounced in such individuals. Within-litter comparisons revealed that animals with a lighter starting mass reached a relatively lower body mass in autumn. Furthermore, there were indications for an allele-specific heterozygote advantage, as animals with heterozygous combinations of the allele Orcu-DRB*4 had relatively lower hepatic coccidia loads than their littermates with certain homozygous allele combinations. Consistent with our hypothesis, significantly higher hepatic coccidia loads and tendentially lower autumn body masses in homozygous compared to heterozygous individuals for the allele Orcu-DRB*4 were evident in initially lighter but not in heavier siblings, suggesting synergistic effects between an unfavourable MHC constitution and a light starting mass. Taken together, these effects might lead to notable differences in fitness among litter siblings, as a low body mass and a high endoparasite burden are key factors limiting young rabbits' survival during winter.

Ovarian cyclicity and prolactin status of African elephants (Loxodonta africana) in North American zoos may be influenced by life experience and individual temperament

Hyperprolactinemia is an endocrine disorder associated with infertility in many species, including elephants. In a recent survey of zoos accredited by the Association of Zoos and Aquariums (AZA), over half of African elephant females (N = 101) were not cycling normally, 30% of which exhibited hyperprolactinemia. We examined whether life experience and temperament predict ovarian cyclicity and circulating prolactin status in individual African elephant females. We hypothesized that, similar to humans, acyclicity and hyperprolactinemia in elephants will be associated with an apprehensive or fearful, anxious temperament, and an increased number of potentially challenging life events (transfers, deaths and births). Ninety-five adult African elephant females housed at 37 AZA institutions were included in this study. Blood samples were collected twice a month for 1 year to determine ovarian cycle (cycling, n = 44; irregular, n = 13; non-cycling, n = 38) and prolactin (normal, n = 44; low; n = 23; high; n = 28) status. Keeper ratings on a 6-point scale were obtained on 32 temperament traits in 85 of these elephants. We determined that giving birth and being exposed to herd mates entering the facility were positively associated with normal ovarian cycle and prolactin profiles. By contrast, age, serum cortisol, and an increased number of herd mates leaving a facility were negatively associated with both. Contrary to our hypothesis, hyperprolactinemia was associated with a popular and caring temperament rating, whereas consistently low prolactin was associated with a fearful, apprehensive temperament. These findings indicate that pituitary-ovarian function may be impacted by life history (cyclicity) and temperament (prolactin), which should be taken into consideration when making management decisions.

An Approach towards Motion-Tolerant PPG-Based Algorithm for Real-Time Heart Rate Monitoring of Moving Pigs

Animal welfare remains a very important issue in the livestock sector, but monitoring animal welfare in an objective and continuous way remains a serious challenge. Monitoring animal welfare, based upon physiological measurements instead of the audio-visual scoring of behaviour, would be a step forward. One of the obvious physiological signals related to welfare and stress is heart rate. The objective of this research was to measure heart rate (beat per minutes) in pigs with technology that soon will be affordable. Affordable heart rate monitoring is done today at large scale on humans using the Photo Plethysmography (PPG) technology. We used PPG sensors on a pig's body to test whether it allows the retrieval of a reliable heart rate signal. A continuous wavelet transform (CWT)-based algorithm is developed to decouple the cardiac pulse waves from the pig. Three different wavelets, namely second, fourth and sixth order Derivative of Gaussian (DOG), are tested. We show the results of the developed PPG-based algorithm, against electrocardiograms (ECG) as a reference measure for heart rate, and this for an anaesthetised versus a non-anaesthetised animal. We tested three different anatomical body positions (ear, leg and tail) and give results for each body position of the sensor. In summary, it can be concluded that the agreement between the PPG-based heart rate technique and the reference sensor is between 91% and 95%. In this paper, we showed the potential of using the PPG-based technology to assess the pig's heart rate.

Deslorelin subcutaneous implants in Oryx dammah males for reproductive control

The aim of this study was to assess the effects of the deslorelin subcutaneous implant as a temporary contraceptive method in the Oryx dammah male. For this purpose, deslorelin at different doses, i.e. 14.1 mg and 9.4 mg, was subcutaneously implanted in three males (Phase 1) and one male (Phase 2) adult Oryx dammah, respectively. Quantitative behavior evaluation and androgen concentrations in feces and plasma were assessed before and after implant application. Fecal androgen concentrations observed in treated males were compared with those measured in one orchiectomized male and two females. Fecal androgen concentrations increased up to 15 days after the implant application, then progressively decreased, reaching the basal level at day150 in Phase 1. In Phase 2, levels remained high until day 60 and returned to basal level on day 120. Plasma testosterone concentration was higher on the day of implant application than three months later, but with variable ranges among males. A general increase of activity levels and hierarchical changes were observed after treatment, in accordance with hormonal variations. Despite males cohabiting with two fertile females during the observation period, no births were recorded. However, between the end of Phase 1 and the beginning of Phase 2, i.e. about 10-11 months after the first deslorelin implant, a fertile mating occurred leading to the birth of a calf. Therefore, we can hypothesize a contraceptive effect up to 10 months after the implant. Testicular histology performed on one male at the end of the Phase 2 showed no spermatogenetic activity. Our results suggest that deslorelin implant can be used to temporarily control reproduction in the Oryx dammah male. Behavior and fecal androgen measurements were useful and repeatable, non-invasive methods to monitor response.

Aggressiveness, Mating Behaviour and Lifespan of Group Housed Rabbit Does

Simple Summary

Aggressiveness is a well-known trait in different animal species, including the European wild and domesticated rabbit. It is one of the main problems in group housing of rabbit does. The aim of the experiment was to investigate the frequency of aggressiveness and mating behaviour as well as the lifespan of does depending on their rank order. Dominance hierarchy developed during aggressive behaviour, i.e., fighting. In most cases the primary position in the rank order was clear. Mating activity was very high after assembling the groups. In addition to male–female mating, some female-female and female-male mounting was also observed, which could lead to pseudo-pregnancy. A second small peak of sexual activity was observed at the end of the hypothetical pseudo-pregnancy. Based on the results it can be concluded that aggressive behaviour is frequent in group housing systems which is contrary to animal welfare. Natural mating is not effective in group-housing systems.

Abstract

Aggressiveness is one of the main problems in group housing of rabbit does. The aim of the experiment was to investigate the frequency of aggressiveness and mating behaviour as well as the lifespan of does depending on group composition. The female and male rabbits were housed in one of the 7.7 m² pens (four females and one male per pen). Based on the ages of female rabbits two homogenous groups (HOM) were formed containing four 17-week-old females and two heterogeneous groups (HET) containing three 17-week-old and one 1-year-old female. Twenty-four-hour video recordings were taken during the first month after assembling the groups, and the aggressive actions (fights) and matings were counted. The lifespan was examined over a 200-day experimental period. On the day after assembling the groups the number of fights among does was high in HET group. The same aggressive behaviour only started a week later in HOM group, and some fights between females and the male were also observed. The daily peaks of aggressiveness were in the morning (after the light on) and in the evening (before and after the lights off). The primary position of females in the hierarchy was clear but sometimes no differences were detected among the subordinate females. The mortality of does was connected with their rank order. The number of matings was very high on the day of assembling the groups and a second small peak was observed at the end of the hypothetical pseudo-pregnancy. In addition to mating between male and females, female–female and female–male mounting was also observed. Despite of the small sample size it seems that aggressive behaviour is frequent in group housing systems, which is contrary to animal welfare. Natural mating is not effective in group-housing system.

Future Directions for Personality Research: Contributing New Insights to the Understanding of Animal Behavior

As part of the European Conference on Behavioral Biology 2018, we organized a symposium entitled, "Animal personality: providing new insights into behavior?" The aims of this symposium were to address current research in the personality field, spanning both behavioral ecology and psychology, to highlight the future directions for this research, and to consider whether differential approaches to studying behavior contribute something new to the understanding of animal behavior. In this paper, we discuss the study of endocrinology and ontogeny in understanding how behavioral variation is generated and maintained, despite selection pressures assumed to reduce this variation. We consider the potential mechanisms that could link certain traits to fitness outcomes through longevity and cognition. We also address the role of individual differences in stress coping, mortality, and health risk, and how the study of these relationships could be applied to improve animal welfare. From the insights provided by these topics, we assert that studying individual differences through the lens of personality has provided new directions in behavioral research, and we encourage further research in these directions, across this interdisciplinary field.

Adrenocortical and bioenergetic responses to cold in laboratory-born northern red-backed voles (Myodes rutilus) from two populations in south Siberia, Russia

In animal populations inhabiting ecologically suboptimal environmental conditions, phenotypical shifts in physiological traits responsible for coping with environmental challenges can be expected. If such variations are of heritable origin, then they will manifest themselves even in individuals bred in captivity. In laboratory-born red-backed voles (Myodes rutilus (Pallas, 1779)) originating from a population with constantly low density, maximum cold-induced metabolic rates were higher than in voles from a high-density population, similar to the data obtained on wild-caught individuals from the same populations. However, unlike wild-caught voles, in laboratory-born individuals maintained under comfortable conditions, we revealed no interpopulation differences either in basal plasma corticosterone level or in corticosterone response to acute cooling. These data confirm the suggestion about the heritable origin of increased maximum cold-induced metabolic rate in a red-backed vole population with relatively low density.

Impact of male presence on female sociality and stress endocrinology in wild house mice (Mus musculus domesticus)

In group living animals, reproductive competition plays an important role in shaping social relationships and associations among female group members. In this study, we investigated the impact of male presence on the development of female-female competition and female sociality in groups of female wild house mice, using physiological and behavioral parameters. We predicted that, by eliciting intra-sexual competition, males influence social relationships among female group members and thus affect female associations to potential cooperation partners. To test this hypothesis we compared stress hormone production, the frequency of agonistic interactions, social hierarchies and social partner preferences in groups of unrelated, unfamiliar females in the absence and presence of males. Our results revealed no indication that the introduction of males into all-female groups of wild house mice elicited increased competition among female group members, neither on the physiological nor on the behavioral level. We found no effect of male presence on female glucocorticoid secretion, aggression, dominance hierarchies or on the females' sociability. Females thus seem not to intensely compete over access to males. This female ability to behaviorally and physiologically deal with even previously unfamiliar same-sex group members may be an important feature of female house mouse societies. In fact, it could be a necessary prerequisite to establish cooperative relationships between females in the context of reproduction, such as communal nursing of young.

Assessment of season-dependent body condition scores in relation to faecal glucocorticoid metabolites in free-ranging Asian elephants

We studied seasonal and annual changes in visual body condition scores (BCSs), and assessed how these scores were related to levels of faecal glucocorticoid metabolites (fGCMs) in free-ranging Asian elephants (Elephas maximus) in the seasonally dry tropical forests of the Mysore and Nilgiri Elephant Reserves in southern India. We assessed the animals' BCS visually on a scale of 1 to 5; where 1 represents a very thin and 5 represents a very fat elephant. To understand the influence of seasonality on BCS, we sampled the population during dry (n = 398) and wet seasons (n = 255) of 2013 and 2015 while, for annual changes in BCS, we sampled nine free-ranging adult females from different family groups that had been repeatedly sighted over seven years. To evaluate the influence of body condition on fGCM, 307 faecal samples were collected from 261 different elephants and were analysed. As a parameter of adrenocortical activity, and thus stress, fGCM was measured (μg/g) in the ethanol-extracted samples using a group-specific 11-oxoaetiocholanolone EIA (antibody raised against 11-oxoaetiocholanolone-17-CMO:BSA and biotinylated-11-oxoaetiocholanolone as a label). Effect of age and season on BCS in relation to fGCM was also studied. A seasonal shift in BCS was observed as expected, i.e. individuals with low BCS were more frequent during the dry season when compared with the wet season. Concentrations of fGCM were highest in individuals with lowest BCS (BCS 1) and then significantly declined till BCS 3. fGCM levels were almost comparable for BCS 3, 4 and 5. This pattern was more conspicuous in female than in male elephants. Season-dependent BCS, hence, reflect the stress status as measured by fGCM, especially in female Asian elephants. This could be used as an important non-invasive approach to monitor the physiological health of free-ranging elephant populations.

Stress responsiveness and anxiety-like behavior: The early social environment differentially shapes stability over time in a small rodent

The early social environment can profoundly affect behavioral and physiological phenotypes. We investigated how male wild cavy offspring, whose mothers had either lived in a stable (SE) or an unstable social environment (UE) during pregnancy and lactation, differed in their anxiety-like behavior and stress responsiveness. At two different time points in life, we tested the offspring's anxiety-like behavior in a dark-light test and their endocrine reaction to challenge in a cortisol reactivity test. Furthermore, we analyzed whether individual traits remained stable over time. There was no effect of the early social environment on anxiety-like behavior and stress responsiveness. However, at an individual level, anxiety-like behavior was stable over time in UE- but not in SE-sons. Stress responsiveness, in turn, was rather inconsistent in UE-sons and temporally stable in SE-sons. Conclusively, we showed for the first time that the early social environment differentially shapes the stability of behavioral and endocrine traits. At first glance, these results may be surprising, but they can be explained by the different functions anxiety-like behavior and stress responsiveness have.

Psychobiological Factors Affecting Cortisol Variability in Human-Dog Dyads

Stress responses within dyads are modulated by interactions such as mutual emotional support and conflict. We investigated dyadic psychobiological factors influencing intra-individual cortisol variability in response to different challenging situations by testing 132 owners and their dogs in a laboratory setting. Salivary cortisol was measured and questionnaires were used to assess owner and dog personality as well as owners' social attitudes towards the dog and towards other humans. We calculated the individual coefficient of variance of cortisol (iCV = sd/mean*100) over the different test situations as a parameter representing individual variability of cortisol concentration. We hypothesized that high cortisol variability indicates efficient and adaptive coping and a balanced individual and dyadic social performance. Female owners of male dogs had lower iCV than all other owner gender-dog sex combinations (F = 14.194, p<0.001), whereas owner Agreeableness (NEO-FFI) scaled positively with owner iCV (F = 4.981, p = 0.028). Dogs of owners high in Neuroticism (NEO-FFI) and of owners who were insecure-ambivalently attached to their dogs (FERT), had low iCV (F = 4.290, p = 0.041 and F = 5.948, p = 0.016), as had dogs of owners with human-directed separation anxiety (RSQ) or dogs of owners with a strong desire of independence (RSQ) (F = 7.661, p = 0.007 and F = 9.192, p = 0.003). We suggest that both owner and dog social characteristics influence dyadic cortisol variability, with the human partner being more influential than the dog. Our results support systemic approaches (i.e. considering the social context) in science and in counselling.

Energetics of stress: linking plasma cortisol levels to metabolic rate in mammals

Physiological stress may result in short-term benefits to organismal performance, but also long-term costs to health or longevity. Yet, we lack an understanding of the variation in stress hormone levels (i.e. glucocorticoids) that exist within and across species. Here, we present comparative analyses that link the primary stress hormone in most mammals (i.e. cortisol) to metabolic rate. We show that baseline concentrations of plasma cortisol vary with mass-specific metabolic rate among cortisol-dominant mammals, and both baseline and elevated concentrations scale predictably with body mass. The results quantitatively link a classical measure of physiological stress to whole-organism energetics, providing a point of departure for cross-species comparisons of stress levels among mammals.

Start early! Does social instability during the pre- and early postnatal development prepare male wild cavies for social challenge later in life?

BACKGROUND

The social environment the mother experiences during pregnancy and lactation can powerfully influence the offspring's behavioural profile. Our previous studies in wild cavies show that two different social environments during pregnancy and lactation bring about different behavioural strategies of male offspring later in life: An unstable social environment leads to a behavioural camouflage strategy, hypothesised to be beneficial at times of socially challenging situations. A stable social environment during early phases of life, however, leads to an early reproduction strategy, expected to be more successful at times of social stability. In the present study, we observed the behavioural strategies of the two types of males in direct comparison in a socially challenging situation: Two adolescent males were placed simultaneously in an unknown social group consisting of one adult male and two females in a semi-naturalistic environment. Cortisol as well as testosterone concentrations and activity levels were compared. Furthermore, paternities were analysed after the males reached sexual maturity. We hypothesised that sons showing a behavioural camouflage strategy are better adapted to cope with this socially challenging situation compared to those displaying an early reproduction strategy.

RESULTS

At the beginning of the experiment, no differences in plasma cortisol concentrations between the males were found, both showed a highly significant increase due to the challenging situation. From day 5 until the end of the experiment (duration = 40 days) sons showing an early reproduction strategy had significantly higher plasma cortisol concentrations compared with those showing a behavioural camouflage strategy. Plasma testosterone concentrations did not differ significantly. Activity levels decreased significantly over time independently of the male's behavioural strategy. Both types of males did not sire offspring during the observation period.

CONCLUSION

Higher cortisol values from day 5 until the end of the experiment in sons showing an early reproduction strategy indicate higher levels of stress in these males compared to those displaying a camouflage strategy. We conclude that the modulation of the males behavioural strategy due to an unstable social environment during early development facilitates the endocrine adaptation to a comparable social situation later in life.

Social and environmental factors modulate leucocyte profiles in free-living Greylag geese (Anser anser)

Background

Blood parameters such as haematocrit or leucocyte counts are indicators of immune status and health, which can be affected, in a complex way, by exogenous as well as endogenous factors. Additionally, social context is known to be among the most potent stressors in group living individuals, therefore potentially influencing haematological parameters. However, with few exceptions, this potential causal relationship received only moderate scientific attention.

Methods

In a free-living and individually marked population of the highly social and long-lived Greylag goose, Anser anser, we relate variation in haematocrit (HCT), heterophils to lymphocytes ratio (H/L) and blood leucocyte counts to the following factors: intrinsic (sex, age, raising condition, i.e. goose- or hand-raised), social (pair-bond status, pair-bond duration and parental experience) and environmental (biologically relevant periods, ambient temperature) factors. Blood samples were collected repeatedly from a total of 105 focal birds during three biologically relevant seasons (winter flock, mating season, summer).

Results

We found significant relationships between haematological parameters and social as well as environmental factors. During the mating season, unpaired individuals had higher HCT compared to paired and family individuals and this pattern reversed in fall. Similarly, H/L ratio was positively related to pair-bond status in a seasonally dependent way, with highest values during mating and successful pairs had higher H/L ratio than unsuccessful ones. Also, absolute number of leucocytes tended to vary depending on raising condition in a seasonally dependent way.

Discussion

Haematology bears a great potential in ecological and behavioural studies on wild vertebrates. In sum, we found that HTC, H/L ratio and absolute number of leucocytes are modulated by social factors and conclude that they may be considered valid indicators of individual stress load.

Social defeat protocol and relevant biomarkers, implications for stress response physiology, drug abuse, mood disorders and individual stress vulnerability: a systematic review of the last decade

INTRODUCTION

Social defeat (SD) in rats, which results from male intraspecific confrontations, is ethologically relevant and useful to understand stress effects on physiology and behavior.

METHODS

A systematic review of studies about biomarkers induced by the SD protocol and published from 2002 to 2013 was carried out in the electronic databases PubMed, Web of Knowledge and ScienceDirect. The search terms were: social defeat, rat, neurotrophins, neuroinflammatory markers, and transcriptional factors.

RESULTS

Classical and recently discovered biomarkers were found to be relevant in stress-induced states. Findings were summarized in accordance to the length of exposure to stress: single, repeated, intermittent and continuous SD. This review found that the brain-derived neurotrophic factor (BDNF) is a distinct marker of stress adaptation. Along with glucocorticoids and catecholamines, BDNF seems to be important in understanding stress physiology.

CONCLUSION

The SD model provides a relevant tool to study stress response features, development of addictive behaviors, clinic depression and anxiety, as well as individual differences in vulnerability and resilience to stress.

The Ecology of Stress: linking life-history traits with physiological control mechanisms in free-living guanacos

BACKGROUND

Providing the context for the evolution of life-history traits, habitat features constrain successful ecological and physiological strategies. In vertebrates, a key response to life's challenges is the activation of the Stress (HPA) and Gonadal (HPG) axes. Much of the interest in stress ecology is motivated by the desire to understand the physiological mechanisms in which the environment affects fitness. As reported in the literature, several intrinsic and extrinsic factors affect variability in hormone levels. In both social and non-social animals, the frequency and type of interaction with conspecifics, as well as the status in social species, can affect HPA axis activity, resulting in changes in the reproductive success of animals. We predicted that a social environment can affect both guanaco axes by increasing the secretion of testosterone (T) and Glucocorticoid (GCs) in response to individual social interactions and the energetic demands of breeding. Assuming that prolonged elevated levels of GCs over time can be harmful to individuals, it is predicted that the HPA axis suppresses the HPG axis and causes T levels to decrease, as GCs increase.

METHODS

All of the data for individuals were collected by non-invasive methods (fecal samples) to address hormonal activities. This is a novel approach in physiological ecology because feces are easily obtained through non-invasive sampling in animal populations.

RESULTS

As expected, there was a marked adrenal (p-value = .3.4e-12) and gonadal (p-value = 0.002656) response due to seasonal variation in Lama guanicoe. No significant differences were found in fecal GCs metabolites between males/females*season for the entire study period (p-value = 0.2839). Despite the seasonal activity variation in the hormonal profiles, our results show a positive correlation (p-value = 1.952e-11, COR = 0.50) between the adrenal and gonadal system. The marked endocrine (r2 = 0.806) and gonad (r2 = 0.7231) response due to seasonal variation in male guanaco individuals highlights the individual's energetic demands according to life-history strategies. This is a remarkable result because no inhibition was found between the axes as theory suggests. Finally, the dataset was used to build a reactive scope model for guanacos.

DISCUSSION

Guanacos cope with the trade-off between sociability and reproductive benefits and costs, by regulating their GCs and T levels on a seasonal basis, suggesting an adaptive role of both axes to different habitat pressures. The results presented here highlight the functional role of stress and gonad axes on a critical phase of a male mammal's life-the mating period-when all of the resources are at the disposal of the male and must be used to maximize the chances for reproductive success.

Stress level, parasite load, and movement pattern in a small-mammal reservoir host for Lyme disease

Occurrence of Lyme disease has increased rapidly in Canada in the past 5 years. The emergence of Lyme disease coincides with the range expansion of the primary host, the white-footed mouse (Peromyscus leucopus (Rafinesque, 1818)), in the region. We evaluated the effects of stress level, parasite load, and forest-patch characteristics on P. leucopus movement pattern. We found negative relations between on the one hand the adrenal gland size, a proxy for stress level, and population density, and on the other hand, home-range area and movement rate of mouse individuals, suggesting that stressed mice cannot maintain a large home range. Population density was also related with excursion (outside the forest patch) and exploration (outside the home range) rates, either directly or through its effect on home-range area and movement rate. Finally, movement rate and excursion rate were lower in individuals infested with more black-legged ticks (Ixodes scapularis Say, 1821). Our results have implication for the mechanism of Lyme disease emergence in the region: individual hosts that carry more ticks and are thus more likely to be spreading the bacterium responsible for Lyme disease are dispersing less than tick-free individuals. Monitoring of Lyme disease should thus consider how the characteristics of host communities modulate the spread of the disease across the landscape.

Excretion patterns of coccidian oocysts and nematode eggs during the reproductive season in Northern Bald Ibis (Geronticus eremita)

Individual reproductive success largely depends on the ability to optimize behaviour, immune function and the physiological stress response. We have investigated correlations between behaviour, faecal steroid metabolites, immune parameters, parasite excretion patterns and reproductive output in a critically endangered avian species, the Northern Bald Ibis (Geronticus eremita). In particular, we related haematocrit, heterophil/lymphocyte ratio, excreted immune-reactive corticosterone metabolites and social behaviour with parasite excretion and two individual fitness parameters, namely, number of eggs laid and number of fledglings. We found that the frequency of excretion of parasites' oocysts and eggs tended to increase with ambient temperature. Paired individuals excreted significantly more samples containing nematode eggs than unpaired ones. The excretion of nematode eggs was also significantly more frequent in females than in males. Individuals with a high proportion of droppings containing coccidian oocysts were more often preened by their partners than individuals with lower excretion rates. We observed that the more eggs an individual incubated and the fewer offspring fledged, the higher the rates of excreted samples containing coccidian oocysts. Our results confirm that social behaviour, physiology and parasite burden are linked in a complex and context-dependent manner. They also contribute background information supporting future conservation programmes dealing with this critically endangered species.

Resilience in farm animals: biology, management, breeding and implications for animal welfare

A capacity for the animal to recover quickly from the impact of physical and social stressors and disease challenges is likely to improve evolutionary fitness of wild species and welfare and performance of farm animals. Salience and valence of stimuli sensed through neurosensors, chemosensors and immunosensors are perceived and integrated centrally to generate emotions and engage physiological, behavioural, immune, cognitive and morphological responses that defend against noxious challenges. These responses can be refined through experience to provide anticipatory and learned reactions at lower cost than innate less-specific reactions. Influences of behaviour type, coping style, and affective state and the relationships between immune responsiveness, disease resistance and resilience are reviewed. We define resilience as the capacity of animals to cope with short-term perturbations in their environment and return rapidly to their pre-challenge status. It is manifested in response to episodic, sporadic or situation-specific attributes of the environment and can be optimised via facultative learning by the individual. It is a comparative measure of differences between individuals in the outcomes that follow exposure to potentially adverse situations. In contrast, robustness is the capacity to maintain productivity in a wide range of environments without compromising reproduction, health and wellbeing. Robustness is manifested in response to persistent or cyclical attributes of the environment and is effected via activity of innate regulatory pathways. We suggest that for farm animals, husbandry practices that incorporate physical and social stressors and interactions with humans such as weaning, change of housing, and introduction to the milking parlour can be used to characterise resilience phenotypes. In these settings, resilience is likely to be more readily identified through the rate of return of variables to pre-challenge or normal status rather than through measuring the activity of diverse stress response and adaptation mechanisms. Our strategy for phenotyping resilience of sheep and cattle during weaning is described. Opportunities are examined to increase resilience through genetic selection and through improved management practices that provide emotional and cognitive enrichment and stress inoculation.