Personality Research in Mammalian Farm Animals: Concepts, Measures, and Relationship to Welfare

A Review of the Effects of Stress on Dairy Cattle Behaviour

In this narrative review, the authors summarise the relationship between stress and behaviour and how dairy cattle cope with stressors. Based on the available literature, the most common stressors in intensive dairy cattle farming, such as pain, disease, heat stress, poor comfort caused by technology, and social stress, are surveyed. The authors describe how these stressors modify the behaviour of dairy cattle, influencing their feeding patterns, social interactions, and overall well-being. Additionally, the review explores the effectiveness of various coping mechanisms employed by dairy cattle to mitigate stress, including physiological adaptations and behavioural responses. This review is a valuable resource for understanding and grading stress in dairy cattle through behavioural reactions. Elucidating the intricate interplay between stressors and behaviour offers insights into potential interventions to improve animal welfare and productivity in dairy farming. Furthermore, this review highlights areas for future research, suggesting avenues for more comprehensive behavioural studies to enhance our understanding of stress management strategies in dairy cattle.

Influence of epinephrine reactivity to stress on meat quality in goats

The magnitude of physiological responses to a stressor can vary among individual goats within a herd; however, whether these differences can differentially affect meat quality is not known. This study was conducted to determine the influence of the magnitude of epinephrine response (ER) to acute stress on muscle metabolome and meat quality in goats. Male Spanish goats (6 mo old) were transported for 180 min. (N = 75 goats; 25 goats/d) to impose stress. Blood samples were obtained after transport for analysis of physiological responses. Goats were slaughtered using humane procedures and samples were collected for muscle metabolomics and meat quality analyses. The data obtained from blood and muscle/meat analysis were then categorized based on epinephrine concentrations into low (LE), medium (ME), and high (HE) ER groups (n = 12/ER group). The physiological and meat quality variables were analyzed as a Completely Randomized Design in SAS, and metabolomics data were analyzed using R software. Plasma glucose concentrations were significantly high in the HE group, low in the LE group, and intermediate in the ME group (P < 0.05). However, leukocyte counts and cortisol, norepinephrine, blood urea nitrogen, and creatine concentrations were not different among the ER groups. Muscle (Longissimus dorsi) glycogen concentrations (15 min postmortem) were significantly higher (P < 0.05) in the ME and LE groups than in the HE group. However, postmortem Longissimus muscle pH and temperature (15 min and 24 h), 24 h calpastatin and desmin levels, and rib chop color (L*, a*, and b*), cooking loss, and Warner-Bratzler shear force values were unaffected by ER. Targeted metabolomics analysis of Longissimus muscle (15 min) revealed that diacyl phosphatidylcholines (C38:0; 40:6) and sphingomyelin (C20:2) were significantly different (P < 0.05) among the ER groups, with the concentrations of these metabolites being consistently high in the LE group. These differential muscle metabolite concentrations suggest that ER can influence biochemical pathways associated with cell membrane integrity and signaling. ER had a significant effect on dopamine concentrations, with the levels increasing with increasing levels of ER. The results indicate that differences in epinephrine reactivity can influence selected physiological responses and muscle metabolites; however, it does not significantly influence meat quality attributes.

Flexible feeding: Dairy cow personality affects changes in feeding behavior and milk production under feed competition conditions

The objective of this study was to determine the effect of individual cow personality traits on feeding behavior and production under low levels of feeding competition, and to determine whether personality traits influence how feeding behavior changes in response to greater feeding competition. Forty-two Holstein cows were assigned to 1 automated feed bin per cow (low competition condition) from 15 to 28 d in milk (DIM; period 1, P1), and 2 feed bins per 3 cows (higher competition condition) from 63 to 76 DIM (period 2, P2). A total mixed ration (TMR) was fed into the automated feed bins which recorded each feed bin visit time, duration, and intake. Cow personality traits were assessed at 21 DIM during P1 and at 70 DIM during P2 using a combined arena test, measuring behavioral responses to a novel environment, novel object, and novel human. Principal components analysis of behaviors observed during the P1 combined arena test revealed 1 factor (interpreted as active-explorative) from the novel environment test explaining 51% of the variance, and 3 factors (interpreted as fearfulness, active-explorative, and sociability toward conspecifics) from each of the novel object (76% cumulative variance) and human (75% cumulative variance) tests. The principal components analysis of behaviors observed during the P2 combined arena test revealed 2 factors jointly from the environment, object, and human tests (interpreted as fearfulness and active-explorative) that together explained 68% of the variance. Fearfulness and active-explorative trait scores were correlated across P1 and P2, indicating stability of personality over a challenging period and advancing DIM. In P2 when competition for feed was increased at greater stage of lactation, the more active-explorative cows appeared to make few alterations to their feeding behavior, yet still maintained their milk yield, compared with lower competition in P1. In contrast, cows who were more fearful increased their feed bin visits from P1 to P2, and less fearful cows increased their eating rate, without increased milk production, despite advanced lactation. Overall, the results indicate that cows of different personalities adopt different feeding strategies in response to a change in their environment, and may benefit from tailored management during challenging periods.

A field approach to observing changes in behavioural welfare indicators over 2 years in stabled horses

In stabled horses, several behaviours are considered to be important indicators of the state of welfare at the individual level: stereotypies, aggressive behaviours towards humans and the "withdrawn", alert, sternal, lateral and observation postures. Until now, these behaviours have been extensively studied in relation to different horse management practices. However, little is known about their changes or consistency over time. This study aimed to investigate differences in the expression of these behaviours assessed on 44 stabled horses during an initial 3-month period and then again on the same individuals 2 years later. Out of the six behaviours studied, two showed significant differences between the 2 years with medium effect sizes: the levels of aggressiveness towards humans increased (Wilcoxon signed-rank test: V = 65, P = 0.005) and those of recumbent rest during the day decreased (V = 416, P < 0.001) over time. The results also suggested limited evidence of major changes over time in the expression of stereotypies, the "withdrawn", alert and observation postures. However, the principal component analyses carried out on all the behaviours showed that alert and observation postures may slightly decrease over time for some individuals. Regarding stereotypies and the "withdrawn" posture, the results mainly suggested a change at the individual level in the expression of these behaviours over time. This study provided new insights into the dynamic nature of several behaviours when the horses' living conditions are not fundamentally altered and raised hypotheses about the state of welfare of stabled individuals over a 2-year period.

Personality Characteristics Predictive of Social Pairing Outcome in Orange-Winged Amazon Parrots (Amazona amazonica)

Most wild parrot species live in flocks, enriched by the environment and conspecific interactions. Captive parrots often live individually and are prone to behavioral maladaptation. If captive parrots and their behavior become intolerable, they are commonly relinquished to rescue organizations. This study aims to create parrot personality assessments for use by rescuers adding newly acquired parrots to shared environments. The study involved 20 orange-winged Amazon parrots (10 M, 10 F). Observers familiar with each bird scored its personality and analyses determined three sets of personalities: Social, Guarded, and Nervous Each parrot was paired with its 10 heterosexual counterparts and its interactions monitored remotely and captured on video. Pairing trials occurred over 72 hours in a specially designed pairing structure. Parrot personality could predict pairing success. Social-Guarded and Social-Nervous were more successfully paired, with individuals maintaining a close distance to one another and displaying increased rest-stretch behavior. Time of day influenced success with Social-Nervous pairs successful at all times of day, Social-Social pairs in the AM, and Guarded-Guarded pairs in the PM period. The study results suggest that rescues can use personality assessment and specific behaviors during cohabitation to predict OWA novel pairing outcomes.

Graduate Student Literature Review: Sociability, fearfulness, and coping style-Impacts on individual variation in the social behavior of dairy cattle

Dairy cattle typically live in groups, but individuals within these groups vary in their social behavior. An improved understanding of factors affecting the expression of social behavior may help refine management practices on farms to better accommodate the needs of all individuals within the herd. In this paper, we review (1) some examples of how social behavior is expressed in cattle, (2) commonly assessed personality traits in this species (i.e., sociability and fearfulness) as well as coping style, and (3) how these can affect the expression of social behavior of dairy cattle and in turn their welfare. We also identify understudied social behaviors that personality might influence (social learning, social stress, and social buffering of negative emotions), and that could inform how to improve the welfare of intensively housed dairy cattle.

Effects of dairy cows' personality traits on their adaptation to an automated milking system following parturition

The objectives of this study were to determine how dairy cow personality traits affect their adaptation to an automated milking system (AMS) upon parturition, as well as whether these personality traits are consistent across the transition from gestation to lactation. Sixty Holstein dairy cows (19 primiparous and 41 multiparous) were assessed for personality traits using a combined arena test conducted at 24 d before parturition and 24 d after first introduction to an AMS, which occurred ∼3 d after parturition. The combined arena test comprised 3 parts: a novel arena test, a novel object test, and a novel human test. Principal component analysis of the behaviors recorded during the personality assessment revealed 3 factors interpreted as personality traits (75% cumulative variance) in the pre-calving test, interpreted as explore, active, and bold. The post-calving test revealed 2 factors (78% cumulative variance), interpreted as active and explore. Data from d 1 to 7 after introduction to the AMS were summarized by cow and associated with the pre-calving factors, and data from d 21 to 27 after introduction to the AMS were summarized by cow and associated with the post-calving factors. The active trait had a moderate positive correlation between the pre- and post-calving tests, whereas exploration had a weak positive correlation between tests. Cows that scored high for activeness in the pre-calving test tended to have fewer fetching events and a higher coefficient of variation of milk yield in the first 7 d after introduction to the AMS, whereas bolder cows tended to have higher milk yield during that period. In the post-calving test, more active cows tended to have more frequent milkings and voluntary visits per day, as well as a lower cumulative milk yield from d 21 to 27 after introduction to the AMS. Overall, these results indicate that personality traits of dairy cows are associated with adaptation and performance in an AMS, and that personality traits are consistent across the transition period. Specifically, cows that scored high for boldness and activeness adapted better to the AMS immediately after calving, whereas cows that scored low for activeness and high for boldness performed better in terms of milk yield and milking activity in early lactation. This study demonstrates that personality traits affect milking activity and milk yield of dairy cows milked with an AMS and, therefore, may be useful for selection of cows who might best adapt to and use an AMS.

Association between personality traits of dairy cows and their peripubertal heifer offspring

This study aimed to determine if personality traits identified in dairy cows during the transition phase are correlated with those of their peripubertal heifer calves. At ~24 d before calving and ~24 d after being first introduced to the automated milking system, the personality traits of 23 Holstein cows were assessed using a combined arena test [consisting of exposure to consecutive novel environment (NE), novel object (NO), and novel human (NH) tests]. Personality traits were established by principal component analysis (PCA) of behaviors expressed in these tests. The PCA of cow behaviors during the precalving test revealed 3 factors, or personality traits, interpreted as exploratory, active, and bold. The PCA of cow behaviors during the postcalving test revealed 2 factors, interpreted as active and exploratory. From these cows, 23 female Holstein heifers were produced and enrolled in this study at 7 mo of age. Heifers were personality tested once through a similar combined arena test. The PCA of heifer behaviors during the NO test revealed 3 factors, interpreted as bold, exploratory-active, and social. The PCA of heifer behaviors during the NH test revealed 2 factors, interpreted as exploratory-active and social. All factor scores from each cow and heifer pair were tested for association. An association between cows with higher scores on the factor interpreted as exploratory and heifers with lower scores on the factor interpreted as bold was detected. There were tendencies for cows with higher scores on the factor interpreted as active to be associated with heifers that scored highly on the factors interpreted as exploratory-active and bold. The data suggests that there are some limited associations between personality traits of cows and their heifer offspring; further exploration of these associations may lead to the prediction of heifer personality based on cow personality.

Contemporary Knowledge on the Assessment of Temperament in Cattle and Its Impact on Production and Reproduction Including Some Immunological, Genetic and Metabolic Parameters

Temperament is associated with the well-being, health, production and reproduction of cattle. In order to increase the population of individuals with the desired temperament, its evaluation should be standardized and be made one of the obligatory elements of breeding and veterinary examination. A number of different tests are used for temperament assessment. In this article, the importance of temperament correlation with some metabolic, genetic, immunological, production and reproductive parameters have been shown, pointing at its influence on the economy and cattle handling. The most common methods for assessing the temperament of cattle are presented, including long-time scales of temperament assessment. At the same time, the relationship of the temperament of cattle with production efficiency, immunity and reproductive indicators has been shown, indicating that its correct assessment is an important aspect of the proper development of the herd and the associated economic growth.

Commercial laying hens exhibit long-term consistent individual differences and behavioural syndromes in spatial traits

Past research has supported the importance of animal personalities for the productivity and welfare of farm animals. However, current assessments of personality traits are commonly conducted over short periods using standardized assays and may not reflect all important aspects of behaviours in commercial settings throughout the production period. This study aimed to evaluate consistent behavioural differences between 194 commercial laying hens within an aviary across most of the production period (eight months). We used five spatial behaviours related to various aspects of commercial hens' daily routine, including the sleeping, feeding, nesting, indoor movements and outdoor usage. All behaviours were repeatable over time and across contexts, with consistent differences between individuals explaining between 23% and 66% of the variation. These long-term consistencies revealed the potential applicability of the behaviours as personality traits of commercial hens. Moreover, we identified behavioural syndromes comprising all behaviours except the nesting-related behaviour, indicating two axes of spatial personalities that may be driven by different mechanisms. We discussed the significance of such individual differences in using personality traits to breed more resilient farm animals. Future research should evaluate associations of these behaviours with animal welfare and productivity to inform breeding efforts.

Context-specific variation and repeatability in behavioral traits of bent-wing bats

Animals may show consistent among-individual behavioral differences over time and in different contexts, and these tendencies may be correlated to one another and emerge as behavioral syndromes. The cross-context variation in these behavioral tendencies, however, is rarely explored with animals in contexts associated with different locomotion modes. This study assessed the variation and repeatability in behavioral traits of bent-wing bats Miniopterus fuliginosus in southern Taiwan, and the effects of contextual settings associated with locomotion mode. The bats were sampled in the dry winter season, and their behaviors were measured in hole-board box (HB) and tunnel box (TB) tests, both suited for quadrupedal movements of the bats, and flight-tent (FT) tests that allowed for flying behaviors. The bats in the FT tests showed more interindividual and between-trial behavioral variation than those in the HB and TB tests. Nearly all of the behaviors in the TB and FT tests, but only half of those in the HB tests, showed medium to high repeatability. These repeatable behaviors were grouped into distinct behavioral traits of boldness, activity, and exploration, which were correlated to one another across contexts. In addition, we observed a consistently higher correlation between behavioral categories across the HB and TB contexts than between either of these contexts and the FT context. The results indicate consistent among-individual behavioral differences across time and contexts in wildly caught bent-wing bats. The findings of behavioral repeatability and cross-context correlations also indicate context-dependent variation and suggest that test devices which allow for flight behaviors, such as flight tents or cages, may provide a more suitable setting for measuring the behaviors and animal personalities of bats, particularly for those species that display less or little quadrupedal movements.

Invited review: Social dominance in dairy cattle: A critical review with guidelines for future research

Cattle are gregarious animals able to form social relationships. Dominance is one of the most widely studied social behaviors of dairy cattle, especially cows confined indoors. However, much of the past dairy cattle research has used an unstandardized approach, differing in definitions and conceptual understanding of dominance, as well as their methods of data collection and dominance calculation. The first of the 3 aims of this review is to evaluate how dominance relates to the social behavior of housed dairy cows. Cows engage in agonistic interactions to establish and reinforce dominance relationships. An individual's dominance is influenced by intrinsic characteristics, such as personality, and extrinsic factors, including group composition. When competing for resources, agonistic interactions can also be influenced by individual motivational differences, such as hunger, which may diminish the role of dominance in regulating competition. Our second aim is to critically review methods used to assess dominance in cows. This includes discussions on the effect of time and location of data collection on measured values as well as the viability and limitations of some dominance calculation methods. We propose that different methodologies lend themselves to different types of research questions. For example, the use of data stream-based methods that consider the sequence of interactions are useful for estimating how dominance fluctuates with changing conditions and can be used in a dynamically changing group. In contrast, matrix-based methods that aggregate social interactions may be best for identifying the social position of individuals and understanding how social characteristics influence the attributes of a stable hierarchy. Our third aim is to discuss the future of dominance research. We use a flowchart to illustrate guidelines for a more standardized approach to measuring dominance in cattle. We also identify areas in need of further conceptual clarification, suggest practical applications of dominance when managing dairy cattle, and discuss some limitations of dominance research.

Fecal cortisol metabolites reflect transport stress in 3-month-old dairy calves pre- and postweaning: A pilot study

Measurement of fecal cortisol metabolites (FGCM) is a well-established, noninvasive method to assess stress in adult dairy cattle. However, this procedure has not yet been validated for unweaned dairy calves, and it can be expected that the milk proportion of the diet may influence the resulting FGCM concentrations. The aim of this study was therefore to assess whether a peak in FGCM concentrations in response to a stressor can be measured in unweaned dairy calves on a largely milk-based diet. If so, further objectives were to examine whether maximum FGCM concentrations, as well as the time lag until they are reached, are comparable to the values in the same calves on a solid-based diet after weaning. For this study, 5 German Holstein calves of about 3 mo of age (93 to 102 d preweaning) were exposed to a 45 min transport stressor once before and once after weaning, which was 3 wk apart. All voided fecal samples were collected for 24 h after termination of the transport. Fecal cortisol metabolites were analyzed with an 11-oxoetiocholanolone enzyme immunoassay and changes in FGCM concentrations relative to the individual baseline (FGCM_rel) were calculated. Results showed a clear peak in FGCM concentrations on both diet types. The peak FGCM_rel concentrations tended to be higher when the calves were on the preweaning diet (at peak: +233 ± 25% increase relative to baseline) in comparison to the postweaning diet (+124 ± 23%). Considering the whole 24 h sampling period, the FGCM_rel concentrations for all calves were significantly higher on the preweaning diet than on the postweaning diet. There was also a numerical difference in the delay between occurrence of the stressor and appearance of the peak FGCM_rel concentrations in feces, as the time lag was 1.5 ± 1.2 h longer when the calves were on the preweaning diet compared with the postweaning diet. In conclusion, our results suggest that FGCM concentrations are a useful stress marker for unweaned dairy calves in the same way they are for older cattle, but that FGCM_rel concentrations tend to be higher in unweaned than in weaned calves and are thus not directly comparable.

Social Reward Behaviour in Two Groups of European Grey Wolves (Canis lupus lupus)-A Case Study

Prosociality occurs in many species and is likely to be a crucial factor for the survival of group-living animals. Social feedback is an important mechanism for the coordination of group decisions. Since group-living animals with specific personality axes, i.e., boldness, are known to provide certain benefits for their group, bold actions might receive more prosocial feedback than other actions. Our case study aims to determine whether bold behaviour, i.e., novel object interaction (Nobj), might be answered more frequently with prosocial behaviours. We investigated the differences in the frequency of occurrence in prosocial behaviours after three different individual actions in two groups of grey wolves. We aim to outline the development of a social reward behavioural category as part of social feedback mechanisms. We used Markov chain models for probability analyses, and a non-parametric ANOVA to test for differences between the influences of individual behaviours on the probability of a prosocial behaviour chain. We additionally tested for the potential influences of age, sex and personality on the frequency of Nobj. Our results suggest that bold interactions are more often responded to with prosocial behaviour. Bold behaviour might be more often socially rewarded because of its benefits for group-living animals. More research is needed to investigate whether bold behaviour is more frequently responded to prosocially, and to investigate the social reward phenomenon.

Intra-individual variation of hen movements is associated with later keel bone fractures in a quasi-commercial aviary

Measuring intra- and inter-individual variation in movement can bring important insights into the fundamental ecology of animals and their welfare. Although previous studies identified consistent differences in movements of laying hens within commercial aviaries, the level of consistency was not quantified, limiting our capacity to understand the importance of individual movements for welfare. We aimed to quantify the scope of intra- and inter-individual differences in movements of commercial laying hens and examined their associations with indicators of welfare at the end of production. We quantified individual differences in one composite daily movement score for 80 hens over 54 days post-transfer to a quasi-commercial aviary. Results showed consistent inter-individual differences in movement averages, explaining 44% of the variation, as well as individual variation in predictability and temporal plasticity (at the population-level, hens increased their movements for 39 days). Hens that were more predictable in their daily movements had more severe keel bone fractures at the end of production while we found no such correlation between daily movement averages (individual intercept) and welfare indicators. Our findings highlight the importance of inter-individual difference in intra-individual variation of movements to improve poultry welfare.

Repeatability of an attention bias test for sheep suggests variable influence of state and trait affect on behaviour

Understanding the effects of repeated testing on behaviour is essential for behavioural tests that are re-applied to the same individuals for research and welfare assessment purposes. Assessing the repeatability of behaviour can also help us understand the influence of persistent traits vs transient states on animal responses during testing. This study examined the repeatability of behavioural responses in an attention bias test developed for sheep as a measure of affective state. Sheep were assessed in the attention bias test three times (n = 81 sheep), with testing occurring at intervals of 1 year then 2 weeks. During testing, individual sheep were exposed to a dog located behind a window for 3 s in a 4 × 4 m arena, then the dog was obscured from view, removed and sheep behaviours were recorded for 180 s. We hypothesised that behaviours in the test would have moderate-high repeatability but that the mean behavioural responses would change over consecutive trials as sheep habituated to the test environment. To estimate repeatability, data were modelled using restricted maximum likelihood linear mixed-effects models, fitting animal ID as a random effect. Vigilance behaviour, defined as having the head at or above shoulder height, was moderately repeatable (r = 0.58). Latency to eat (r = 0.20) and duration spent looking towards the previous location of the dog (attention to the dog wall) (r = 0.08) had low repeatability. Mean latency to eat did not differ significantly between trials (P = 0.2) and mean vigilance behaviour tended to decrease over the trials (P = 0.07). Mean duration of attention to the dog wall significantly decreased across the trials (P < 0.001), while mean zones crossed increased (P < 0.001), as did behaviours directed towards the exit door such as duration in proximity and pawing at the door. Overall, vigilance behaviour was moderately repeatable, suggesting it may have been driven by temperament or personality traits, while attention and feeding behaviours may have been more influenced by transient affective states or other factors, however further research is needed to better tease apart these potential effects. Sheep demonstrated some habituation to the test over consecutive trials. Care should therefore be taken during future application of the test to ensure all animals undergoing attention bias testing have equivalent experience for a valid interpretation of their relative behavioural responses.

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.

Personality of individually housed dairy-beef crossbred calves is related to performance and behavior

The aim of this study was to evaluate differences in behavioral responses of individually housed dairy-beef crossbred calves to standardized personality tests (novel person, novel object, and startle test) and investigate associations of personality traits with performance and home pen behavior. Dairy-beef crossbred (Holstein x Angus) calves (n=29) were individually housed with ad libitum access to water and calf starter. Body weight was measured weekly and calf starter intake was recorded daily from day of arrival (8.5 ± 2.1; experimental day 1) for 76 days. Behavior within the home pen (eating, drinking, non-nutritive oral manipulation) and activity were recorded on experimental days 13, 32, 53, and 67 using a camera and a pedometer. The calves were subjected to standardized personality tests in their home pen at the end of the experimental period (80.7 ± 2.0 d of age), including a novel person test (stationary person in the corner of their home pen) and combined novel object/startle test (remote-controlled car in the pen, that suddenly moved when touched). A principal component analysis on the behaviors recorded from the tests (latency to approach person or object, time spent attentive and touching the person or object, and time spent inactive, playing and grooming) yielded 3 factors that explained 76.1% of the variance, and were interpreted as personality traits labeled “fearful”, “inactive”, and “bold”. These factors were examined in regression analyses for their associations with home pen behavior and performance. The factor “fearful” had negative associations with total average daily gain and average grain intake. In contrast, the factor “inactive” had positive associations with non-nutritive oral manipulation of buckets or walls. The factor “bold” had no significant association with any of the performance or home pen behavior measures. In conclusion, personality traits identified from standardized tests were related to performance and home pen behavior measures in individually housed, crossbred calves. These results complement work in group housed calves suggesting personality testing may be useful selective tools to identify high and low performing calves from an early age.

Internally Triggered Experiences of Hedonic Valence in Nonhuman Animals: Cognitive and Welfare Considerations

Do any nonhuman animals have hedonically valenced experiences not directly caused by stimuli in their current environment? Do they, like us humans, experience anticipated or previously experienced pains and pleasures as respectively painful and pleasurable? We review evidence from comparative neuroscience about hippocampus-dependent simulation in relation to this question. Hippocampal sharp-wave ripples and theta oscillations have been found to instantiate previous and anticipated experiences. These hippocampal activations coordinate with neural reward and fear centers as well as sensory and cortical areas in ways that are associated with conscious episodic mental imagery in humans. Moreover, such hippocampal “re- and preplay” has been found to contribute to instrumental decision making, the learning of value representations, and the delay of rewards in rats. The functional and structural features of hippocampal simulation are highly conserved across mammals. This evidence makes it reasonable to assume that internally triggered experiences of hedonic valence (IHVs) are pervasive across (at least) all mammals. This conclusion has important welfare implications. Most prominently, IHVs act as a kind of “welfare multiplier” through which the welfare impacts of any given experience of pain or pleasure are increased through each future retrieval. However, IHVs also have practical implications for welfare assessment and cause prioritization.

DNA methylation landscapes from pig's limbic structures underline regulatory mechanisms relevant for brain plasticity

Epigenetic dynamics are essential for reconciling stress-induced responses in neuro-endocrine routes between the limbic brain and adrenal gland. CpG methylation associates with the initiation and end of regulatory mechanisms underlying responses critical for survival, and learning. Using Reduced Representation Bisulfite Sequencing, we identified methylation changes of functional relevance for mediating tissue-specific responses in the hippocampus, amygdala, hypothalamus, and adrenal gland in pigs. We identified 4186 differentially methylated CpGs across all tissues, remarkably, enriched for promoters of transcription factors (TFs) of the homeo domain and zinc finger classes. We also detected 5190 differentially methylated regions (DMRs, 748 Mb), with about half unique to a single pairwise. Two structures, the hypothalamus and the hippocampus, displayed 860 unique brain-DMRs, with many linked to regulation of chromatin, nervous development, neurogenesis, and cell-to-cell communication. TF binding motifs for TFAP2A and TFAP2C are enriched amount DMRs on promoters of other TFs, suggesting their role as master regulators, especially for pathways essential in long-term brain plasticity, memory, and stress responses. Our results reveal sets of TF that, together with CpG methylation, may serve as regulatory switches to modulate limbic brain plasticity and brain-specific molecular genetics in pigs.

Looking beyond the Shoal: Fish Welfare as an Individual Attribute

Simple Summary

The fish farming industry is characterized by settings where large numbers of fishes are raised together at high stocking densities, effectively obliterating the individual. Given that animal welfare is an individual attribute that refers to how an animal experiences her world, it follows that ensuring good welfare for the different individuals is difficult in fish farms. In this paper we review evidence supporting the notion that fishes are individuals and fish welfare should thus also be considered at the individual level, examine the ways that animal welfare is assessed in fish farms, evaluate these practices in light of individualized terrestrial animal welfare assessment methods, and make recommendations regarding research that could lead to a better understanding of how to provide each individual fish with good welfare in captivity.

Abstract

Welfare is an individual attribute. In general, providing captive nonhuman animals with conditions conducive to good welfare is an idea more easily applied when dealing with few individuals. However, this becomes much harder—if not impossible—under farming conditions that may imply high numbers of animals living in large group sizes. Although this is a problem inherent to intensive animal farming, it is possibly best exemplified in fish farming, for these practices often rely on extremely high numbers. In this paper we review evidence supporting the notion that fishes are individuals and fish welfare should thus also be considered at the individual level, examine the current state of welfare assessment in the aquaculture industry, evaluate these practices in light of individualized terrestrial animal welfare assessment methods, and make recommendations regarding research that could lead to a better understanding of how to provide each individual fish with good welfare in captivity.

The glutamate metabotropic receptor 5 (GRM5) gene is associated with beef cattle home range and movement tortuosity

Background

The grazing behaviour of herbivores and their grazing personalities might in part be determined genetically, but there are few studies in beef cattle illustrating this. In this study, we investigated for first time the genetic variation within a candidate ‘grazing gene’, the glutamate metabotropic receptor 5 gene (GRM5), and tested associations between variation in that gene and variation in grazing personality behaviours (GP-behaviours) displayed by free-ranging cows during winter grazing in the steep and rugged rangelands of New Zealand. Mature beef cows (n = 303, from 3 to 10 years of age) were tracked with global positioning system (GPS) and, with 5-minutes (min) relocation frequency, various GP-behaviours were calculated. These included horizontal and vertical distances travelled, mean elevation, elevation range, elevation gain, slope, home range and movement tortuosity, variously calculated using daily relocation trajectories with repeated measurements (i.e., 7 to 24 days (d)) and satellite-derived digital elevation models (DEM). The different GP-behaviours were fitted into mixed models to ascertain their associations with variant sequences and genotypes of GRM5.

Results

We discovered three GRM5 variants (A, B and C) and identified the six possible genotypes in the cattle studied. The mixed models revealed that A was significantly associated with elevation range, home range and movement tortuosity. Similarly, GRM5 genotypes were associated (P < 0.05) to home range and movement tortuosity, while trends suggesting association (P <  0.1) were also revealed for elevation range and horizontal distance travelled. Most GP-behaviour models were improved by correcting for cow age-class as a fixed factor. The analysis of GP-behaviours averaged per cow age-class suggests that grazing personality is fully established as beef cows reached 4 years of age. Home range and movement tortuosity were not only associated with GRM5 variation, but also negatively correlated with each other (r = − 0.27, P < 0.001).

Conclusions

There seems to be a genetically determined trade-off between home range and movement tortuosity that may be useful in beef cattle breeding programmes aiming to improve the grazing distribution and utilisation of steep and rugged rangelands.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40104-022-00755-7.

Survey-rated personality traits and experimentally measured coping style and stress reactivity, in wild baboons

The coping style and stress reactivity framework for individual differences in the stress response has been of increasing utility within primatological research. Such differences are often quantified using an experimental approach, but many primatological studies have historically been reliant on a personality-like framework. The personality-like research is derived from human personality literature using survey ratings, while approaches focused on coping styles are often used to interpret differences in small rodents and birds. Experimental approaches benefit from a constrained situation that facilitates control, but sacrifice utility via the generalizability afforded via ratings. Resolving how these two theoretical and methodological approaches intersect is paramount to establishing a biological synthesis between two robust fields of research on individual differences. We applied these frameworks to adult wild olive baboons (Papio anubis) at a field site in Laikipia, Kenya. We quantified coping style and stress reactivity using individually targeted field experiments. We quantified personality trait differences using observer ratings of the monkeys. We isolated three personality trait factors: Neuroticism, Assertiveness, and Friendliness. Personality trait differences showed little association with coping style, but Neuroticism was predicted by stress reactivity.

Social behavior in farm animals: Applying fundamental theory to improve animal welfare

A fundamental understanding of behavior is essential to improving the welfare of billions of farm animals around the world. Despite living in an environment managed by humans, farm animals are still capable of making important behavioral decisions that influence welfare. In this review, we focus on social interactions as perhaps the most dynamic and challenging aspects of the lives of farm animals. Social stress is a leading welfare concern in livestock, and substantial variation in social behavior is seen at the individual and group level. Here, we consider how a fundamental understanding of social behavior can be used to: (i) understand agonistic and affiliative interactions in farm animals; (ii) identify how artificial environments influence social behavior and impact welfare; and (iii) provide insights into the mechanisms and development of social behavior. We conclude by highlighting opportunities to build on previous work and suggest potential fundamental hypotheses of applied relevance. Key areas for further research could include identifying the welfare benefits of socio–positive interactions, the potential impacts of disrupting important social bonds, and the role of skill in allowing farm animals to navigate competitive and positive social interactions. Such studies should provide insights to improve the welfare of farm animals, while also being applicable to other contexts, such as zoos and laboratories.

Exposure to humans after weaning does not reduce the behavioural reactivity of extensively reared Merino lambs

Human-directed fear in extensively reared sheep is often high due to the aversive nature of common husbandry procedures and infrequent interactions with humans. This study investigated whether additional human exposure provided to weaned lambs reduced human-directed fear and behavioural reactivity. Ninety Merino lambs were either exposed to low or moderately stressful human exposure sessions, or had no additional human contact, and their fear responses and behavioural reactivity to humans, a startle stimulus and confinement were tested. Overall, the imposed interventions did not reduce behavioural reactivity during these tests, suggesting fear towards humans had not been altered.

Personality traits affect learning performance in dwarf goats (Capra hircus)

A wide range of species exhibit time- and context-consistent interindividual variation in a number of specific behaviors related to an individual's personality. Several studies have shown that individual differences in personality-associated behavioral traits have an impact on cognitive abilities. The aim of this study was to investigate the relationship between personality traits and learning abilities in dwarf goats. The behavior of 95 goats during a repeated open field (OF) and novel object test (NO) was analyzed, and two main components were identified using principal component analysis: boldness and activity. In parallel, the goats learned a 4-choice visual initial discrimination task (ID) and three subsequent reversal learning (RL) tasks. The number of animals that reached the learning criterion and the number of trials needed (TTC) in each task were calculated. Our results show that goats with the lowest learning performance in ID needed more TTC in RL1 and reached the learning criterion less frequently in RL2 and RL3 compared to animals with better learning performance in ID. This suggests a close relationship between initial learning and flexibility in learning behavior. To study the link between personality and learning, we conducted two analyses, one using only data from the first OF- and NO-test (momentary personality traits), while the other included both tests integrating only animals that were stable for their specific trait (stable personality traits). No relationship between personality and learning was found using data from only the first OF- and NO-test. However, stability in the trait boldness was found to have an effect on learning. Unbold goats outperformed bold goats in RL1. This finding supports the general hypothesis that bold animals tend to develop routines and show less flexibility in the context of learning than unbold individuals. Understanding how individual personality traits can affect cognitive abilities will help us gain insight into mechanisms that can constrain cognitive processing and adaptive behavioral responses.

Viral infection changes the expression of personality traits in an insect species reared for consumption

Disease-induced personality change results from endogenous and adaptive host responses or parasitic manipulation. Within animal husbandry systems understanding the connection between behaviour and disease is important for health monitoring and for designing systems considerate to animal welfare. However, understanding these relationships within insect mass-rearing systems is still in its infancy. We used a simple repeated behavioural-emergence test to examine parasite-induced differences in group personality traits in the house cricket Acheta domesticus, by comparing the behaviours of 37 individuals infected with the Acheta domesticus densovirus (AdDV) and 50 virus-free individuals. AdDV-infected animals had a much lower emergence probability, longer times until emergence, and did not change their behaviour with experience compared to the virus-free animals. AdDV-infected animals also had lower variation in their probability of emergence within the population, most likely related to animals displaying a relatively uniform sickness response. These infected animals also had higher variation in their response to experimental trial experience; this greater variation resulted from a difference between males and females. Infected females responded to experience in a similar way as virus-free animals, while AdDV-infected males showed a response to experience in the opposite direction: i.e., while all other groups reduced emergence time with experience, infected males always increased their mean emergence time as trials progressed. Our results are important not only in the context of animal personality research, but also with regards to creating husbandry systems and disease monitoring within the insects-as-food industry that are considerate to both production traits and animal welfare.

Personality matters: exploring the relationship between personality and stress physiology in captive African lions

Background

Considering animals as individuals and not as species is becoming increasingly essential to animal welfare management in captive settings. Recent studies on big cat personalities and coping strategies suggest personality can help big cats cope in their surroundings. Yet a large portion of the published literature focuses on understanding either the personality or stress physiology of big cats. Our research shows how integrating an improved understanding of the personality of big cats with stress physiology may enhance welfare, especially for endangered species like African lions. By using a wild cat personality checklist, this study compared the key personality dimensions of 22 African lions with its faecal glucocorticoids and assessed factors influencing their personality and stress physiology.

Results

We found two reliable personality dimensions for African lions (dominance and agreeableness) and identified key factors (sex, age and location) that may influence their personality. Further, on testing if these factors influenced the stress physiology through variations in glucocorticoid levels, there was no significant difference. However, there was a strong negative association between agreeableness and glucocorticoid levels. These results suggest that the behavioural traits loading positively and higher for agreeableness are associated with lower glucocorticoid stress levels, which may assist a lion to cope with stressors in its surroundings.

Conclusions

Our findings highlight this integrated approach of linking personality and stress physiology of big cats can be beneficial for caretakers. For example, during stressful veterinary procedures or in reintroduction programs, recognizing the personality of lions can help in designing or providing them with resources that will alleviate stress. Thus, there is a need for more interdisciplinary approaches that will contribute towards enhancing the individual and overall welfare of big cats.

Repeatability and Predictability of Calf Feeding Behaviors-Quantifying Between- and Within-Individual Variation for Precision Livestock Farming

Individual calves show substantial between- and within-individual variation in their feeding behavior, the existence and extent of which are not fully researched. In this study, 57,196 feeding records, collected by a computerized milk feeder from 48 pre-weaned calves over 5 weeks, were collated and analyzed for individual differences in three different feeding behaviors using a multi-level modeling approach. For each feeding behavior, we quantified behavioral variation by calculating repeatability and the coefficient of variation in predictability. Our results indicate that calves differed from each other in their average behavioral expression (behavioral type) and in their residual, within individual variation around their behavioral type (predictability). Feeding rate and total meals had the highest repeatability (>0.4) indicating that substantial, temporally stable between-individual differences exist for these behaviors. Additionally, for some behaviors (e.g., feeding rate) calves varied from more to less predictable whereas for other behaviors (e.g., meal size) calves were more homogenous in their within-individual variation around their behavioral type. Finally, we show that for individual calves, behavioral types for feeding rate and total meals were positively correlated which may suggest the existence of an underlying factor responsible for driving the (co)expression of these two behaviors. Our results highlight how the application of methods from the behavioral ecology literature can assist in improving our understanding of individual differences in calf feeding behavior. Furthermore, by uncovering consistencies between individual behavioral differences in calves, our results indicate that animal personality may play a role in driving variability in calf feeding behavior.

Responsiveness of domesticated goats towards various stressors following long-term cognitive test exposure

Current evidence suggests that frequent exposure to situations in which captive animals can solve cognitive tasks may have positive effects on stress responsiveness and thus on welfare. However, confounding factors often hamper the interpretation of study results. In this study, we used human-presented object-choice tests (in form of visual discrimination and reversal learning tests and a cognitive test battery), to assess the effect of long-term cognitive stimulation (44 sessions over 4-5 months) on behavioural and cardiac responses of female domestic goats in subsequent stress tests. To disentangle whether cognitive stimulation per se or the reward associated with the human-animal interaction required for testing was affecting the stress responsiveness, we conditioned three treatment groups: goats that were isolated for participation in human-presented cognitive tests and rewarded with food ('Cognitive', COG treatment), goats that were isolated as for the test exposure and rewarded with food by the experimenter without being administered the object-choice tests ('Positive', POS treatment), and goats that were isolated in the same test room but neither received a reward nor were administered the tests ('Isolation', ISO treatment). All treatment groups were subsequently tested in four stress tests: a novel arena test, a novel object test, a novel human test, and a weighing test in which goats had to enter and exit a scale cage. All treatment groups weretested at the same two research sites, each using two selection lines, namely dwarf goats, not selected for production traits, and dairy goats, selected for high productivity. Analysing the data with principal component analysis and linear mixed-effects models, we did not find evidence that cognitive testing per se (COG-POS contrast) reduces stress responsiveness of goats in subsequent stress tests. However, for dwarf goats but not for dairy goats, we found support for an effect of reward-associated human-animal interactions (POS-ISO contrast) at least for some stress test measures. Our results highlight the need to consider ontogenetic and genetic variation when assessing stress responsiveness and when interacting with goats.

Affective State Recognition in Livestock—Artificial Intelligence Approaches

Simple Summary

Emotions or affective states recognition in farm animals is an underexplored research domain. Despite significant advances in animal welfare research, animal affective state computing through the development and application of devices and platforms that can not only recognize but interpret and process the emotions, are in a nascent stage. The analysis and measurement of unique behavioural, physical, and biological characteristics offered by biometric sensor technologies and the affiliated complex and large data sets, opens the pathway for novel and realistic identification of individual animals amongst a herd or a flock. By capitalizing on the immense potential of biometric sensors, artificial intelligence enabled big data methods offer substantial advancement of animal welfare standards and meet the urgent needs of caretakers to respond effectively to maintain the wellbeing of their animals.

Abstract

Farm animals, numbering over 70 billion worldwide, are increasingly managed in large-scale, intensive farms. With both public awareness and scientific evidence growing that farm animals experience suffering, as well as affective states such as fear, frustration and distress, there is an urgent need to develop efficient and accurate methods for monitoring their welfare. At present, there are not scientifically validated ‘benchmarks’ for quantifying transient emotional (affective) states in farm animals, and no established measures of good welfare, only indicators of poor welfare, such as injury, pain and fear. Conventional approaches to monitoring livestock welfare are time-consuming, interrupt farming processes and involve subjective judgments. Biometric sensor data enabled by artificial intelligence is an emerging smart solution to unobtrusively monitoring livestock, but its potential for quantifying affective states and ground-breaking solutions in their application are yet to be realized. This review provides innovative methods for collecting big data on farm animal emotions, which can be used to train artificial intelligence models to classify, quantify and predict affective states in individual pigs and cows. Extending this to the group level, social network analysis can be applied to model emotional dynamics and contagion among animals. Finally, ‘digital twins’ of animals capable of simulating and predicting their affective states and behaviour in real time are a near-term possibility.

Cattle acclimate more substantially to repeated handling when confined individually in a pen than when assessed as a group

Chute (CS) and exit (ES) scores are common subjective methods used to evaluate temperament in cattle production systems. A pen test, which allows behavior to be observed in a non-restrained setting, may also be an effective method to evaluate temperament by allowing more variation among animals to be expressed. The merit of pen scores in assisting producers in evaluating temperament is equivocal. The objectives of this study were to validate the usefulness of a pen score in delineating temperamental cattle and to determine whether these behavioral scores change under repeated and routine management. Over 3 consecutive years, a factorial design of two measurement protocols (frequent [F], infrequent [IN]) and three recording periods was used. The F measurements were collected over 3 consecutive days and IN measurements only on day 1 within a recording period. Each year, 20 mostly Angus commercial Bos taurus heifers were randomly assigned to each protocol. Behavior was measured using a CS, ES, and exit velocity. Body temperature and heart rate also were recorded. A fecal and blood sample were collected and analyzed for levels of various metabolites including glucose concentration and serum cortisol. Following routine handling, each heifers’ response to 30 s of exposure to a human stressor was recorded both individually and in groups of four. An individual (IPS) and group (GPS) pen scores were assigned from 1 (docile) to 6 (aggressive). For all heifers, protocol, event, and their interaction, were compared on the first day of an event. For F heifers, event and day within event were instead used. Body weight was included as a covariate, with sire and year fitted as random effects. Reliability of IPS and GPS were determined using a kappa (K) coefficient. Both IPS and GPS were reliably assigned (K = 0.64 and 0.44 for IPS and GPS, respectively) and positively correlated with body temperature, heart rate, glucose, and serum cortisol (r = 0.28 to 0.37). Furthermore, F heifers acclimated to repeated handling in an individual pen setting (P < 0.05) while acclimation to handling within groups was not evident (P > 0.14). IPS provides a reliable evaluation of temperament in a non-restrained setting that is indicative of an animal’s response to stress and may be useful when attempting to make phenotypic selection decisions. However, temperamental heifers became calmer with repeated gentle handling.

Chute and exit scores are common subjective methods used to evaluate temperament in cattle production systems. A pen test, which allows behavior to be observed in a non-restrained setting, may also be an effective method to evaluate temperament by allowing more variation among animals to be expressed. However, the merit of pen scores in assisting producers in evaluating temperament has yet to be discerned. Therefore, the objectives of this study were to validate the usefulness of pen scores in delineating temperamental cattle and to determine whether these behavioral scores change under repeated and routine management. Pen scores collected on heifers either individually or as a group could be assigned reliably and were indicative of an animal’s response to stress during normal handling practices. Temperamental heifers, when handled more frequently, acclimated to repeated handling in an individual pen setting but not in a group. Therefore, regardless of method, when cattle are excitable during their first handling experience, more than one observation of temperament may be beneficial before assessing temperament.

Exploration of early social behaviors and social styles in relation to individual characteristics in suckling piglets

Social behavior is a key component of pig welfare on farms, but little is known on the development of social behaviors in piglets. This study aimed to explore social behaviors and identify early social styles in suckling piglets. Social behaviors of 68 piglets from 12 litters were scored continuously for 8 h per day at 21 and 42 days of age, and were included in a Hierarchical Clustering on Principal Components analysis to identify clusters of pigs with similar social styles. Social nosing represented 78% of all social interactions given. Three social styles were identified: low-solicited inactive animals (inactive), active animals (active), and highly-solicited avoiders (avoiders). Belonging to a cluster was independent of age, but was influenced by sex, with females being more represented in the ‘inactive’ cluster, and males in the ‘active’ cluster, whereas both sexes were equally represented in the ‘avoider’ cluster. Stability of piglets’ allocation to specific clusters over age was high in the ‘inactive’ (59%) and ‘active’ (65%) clusters, but low in the ‘avoider’ cluster (7%). Haptoglobin and growth rate were higher in ‘active’ than ‘inactive’ pigs, and intermediate in ‘avoiders’. Our findings suggest the existence of transient social styles in piglets, likely reflective of sexual dimorphism or health status.

Linking the roles of personality and stress physiology for managing the welfare of captive big cats

Animal welfare is important for the humane treatment of animals under our care. Zoos and rescue centres manage various charismatic animals, such as big cats, with limited resources. It is therefore essential for caretakers to understand the needs of an individual big cat to ensure its welfare. However, these needs may differ due to a big cat's personality, which may be identified by its coping style in a stressful situation. In addition, stress is one of the major factors affecting animal welfare. There is limited evidence showing strong associations between personality and stress physiology in big cats. This review focuses on the integration of personality and stress physiology of captive big cats, to highlight possible improvements in their husbandry. Our review identifies key factors that may influence big cat responses to stressors. These influencing factors include: i) social interactions; ii) environment; iii) life history and evolutionary traits; iv) genetics; and v) health. The first two factors are relatively well covered in the literature; however, the final three are potentially very promising avenues for future research to better understand how we can improve big cat welfare.

Dairy Cattle Response to a Virtual Fence When Pasture on Offer Is Restricted to the Post-grazing Residual

Pasture-based dairy systems rely on the accurate allocation of pasture to both meet livestock requirements and maintain the growth of herbage. Currently, physical fences are used to contain livestock however they can be labor-intensive to shift and maintain. Alternatively, virtual fence (VF) systems offer flexibility and real-time control of livestock location. Pre-commercial neckbands (eShepherd®, Agersens, Melbourne, VIC) emit a warning audio tone (AT) when a cow approaches a VF boundary, paired with an electrical pulse (EP) if the cow continues forward into the exclusion zone (EZ). However, the ability of VF technology to control animal location when pasture is restricted to the previous day's residual, remains unknown. Ten non-lactating Holstein-Friesian dairy cows were trained to use a VF system for 6 days before strip grazing a 1.2 ha paddock of annual ryegrass. Over 10 days the cows grazed eight pasture allocations at a pre-grazing pasture mass of 2,324 ± 81 kg DM/ha (mean ± SE) and post-grazing pasture-mass (post-grazing residual) of 1,649 ± 48 kg/DM/ha with a front VF. The allocations had a physical backing fence that included the fresh allocation and a small area of residual to cater for any GPS drift of the front VF. On each day, with the exception of days 5 and 10, the VF was moved forward, and the cows were provided a new pasture allocation. On days 5 and 10, the VF was not shifted, and cows were only offered the previous allocation's residual pasture. The location of each animal (inclusion, buffer, and exclusion zones) and number of stimuli (AT and EP) delivered were recorded. The number of stimuli delivered between the grazing and hold-off days was similar. Cows spent 89% of time within the inclusion zone (IZ), with significant peaks observed on day 5 and 10. Distance that cows traveled into the EZ reduced across time. There was also evidence of individual variation in the number of stimuli and thus time spent in each zone. Overall, the VF system was successful in containing the dairy cows during strip grazing even when only offered the previous days post-grazing residual.

Sheep's coping style can be identified by unsupervised machine learning from unlabeled data

The objective of this study was to define coping style of sheep by using unsupervised machine learning approaches. A total of 105 Norduz sheep (age 3-5 years) were subjected to a 5-minute arena test. Agglomerative Hierarchical Clustering (HCA) was performed on scores of selected principal components retained from Principal Components Analysis (PCA) on arena behaviors to identify sheep coping style. Initially, the variables retained for the PCA were determined with Bartlett's test for sphericity and Kaiser-Meyer-Olkin (KMO) measure of sample adequacy. Seven behavioral variables with KMO values greater than 0.5 were used for final PCA: the average distance to group sheep (DTG), the average distance to stimulus (DTS), the duration of locomotion (LOC), the total number of zone boundaries crossed during the test (CRS), the total number of times that tested sheep sniffed stimulus (NSS), latency to the first sniff the stimulus (LSS), and subjective scores (SCR) scored by an observer on a scale from 1 to 5 (1: extremely calm, 5: extremely restless). The first two components, which were the only ones with an eigenvalue greater than one, accounted for 70.32% of the total variation and were used for clustering analysis. Clustering tendency showed that the scores for the first two components were suitable for clustering (Hopkins' H = 0.852). Several cluster validity indexes were used to obtain aggregated results to determine the most appropriate clustering method and number of clusters. Five different clustering methods: k-means and hierarchical clustering with Ward, average, single and complete linkage were compared. Bootstrap resampling was used to evaluate the stability of a given cluster using the Jaccard coefficient. The clustering method and number of clusters corresponding to the highest rank aggregation score from the bootstrap resampling indicate that the hierarchical clustering method with average linkage and 5 clusters is the most suggested clustering method. However, Ward's algorithm identified the strongest clustering structure for hierarchical clustering, as it had the highest agglomerative coefficient value (0.98). When both Jaccard and aggregation scores are considered together, Ward's method with 3 clusters was selected as the most appropriate method. Sheep were classified into three coping styles (CS) based on HCA results as reactive (Cluster 1, n = 71), intermediate (Cluster 2, n = 22) or proactive (Cluster 3, n = 12). Coping style had significant effect on behavioral variables, DTG, DTS, LOC, CRS and NSS (P < 0.05). The individuals that have proactive coping style had the highest mean values for the variables DTG, DTS and LOC and SCR (P < 0.0001). This indicates that proactive sheep are more active then reactive sheep. The CRS, LOC and NSS mean values were higher for intermediate sheep compared to reactive sheep (P < 0.05). The NSS values were higher for intermediate sheep compare to proactive sheep (P < 0.0001). The findings of the current study show that distinct coping styles in sheep may be identified based on behaviors recorded in an arena test. The findings also revealed that sheep's coping style can be objectively identified by unsupervised machine learning from unlabeled behavioral data.

Housing and personality effects on judgement and attention biases in dairy cows

Affective states can be inferred from responses to ambiguous and threatening stimuli, using Judgement Bias Tasks (JBTs) and Attention Bias Tasks (ABTs). We investigated the separate and interactive effects of personality and housing conditions on dairy cattle affective states. We assessed personality in 48 heifers using Open-Field, Novel-Object and Runway tests. Personality effects on responses to the JBT and to the ABT were examined when heifers were housed under reference conditions. Heifers were subsequently housed under positive or negative conditions, and housing effects on animal responses in both tasks were investigated while controlling for personality. A Principal Component Analysis revealed three personality traits labelled Activity, Fearfulness and Sociability. Under reference conditions, personality influenced heifers' responses to the JBT and to the ABT, therefore questioning the tasks' generalizability across individuals. Against expectations, housing did not influence responses to the  JBT and heifers in the negative conditions looked at the threat later than heifers in the positive or reference conditions. More research is warranted to confirm the validity and the repeatability of the JBT and of the ABT as appropriate measures of affective states in dairy cows.

The effects of cow dominance on the use of a mechanical brush

An animal's social position within a group can influence its ability to perform important behaviours like eating and resting, but little is known about how social position affects the ability to express what are arguably less important but still rewarding behaviors, such as grooming. We set out to assess if dominance measured at the feeder is associated with increased use of a mechanical brush. Over a 2-year period, 161 dry cows were enrolled in a dynamically changing group of 20 individuals with access to a mechanical brush. We determined dominance using agonistic behaviors at the feeder and retrospectively analyzed brush use for the 12 most, and 12 least dominant individuals during the week before calving. Cows that were more dominant at the feeder used the brush more, especially during peak feeding times. Agonistic interactions at the brush did not differ between dominants and subordinates and were not related to brushing duration. These findings indicate that social position, calculated using competition for feed, affects mechanical brush access such that subordinates use the brush less than dominant cows independent of competition or time of day.

Individual differences in behaviour and gut bacteria are associated in collared peccary (Mammalia, Tayassuidae)

AIMS

We tested the hypothesis that the behaviour of an individual is associated with the diversity of its gut bacteria, using the collared peccary (Pecari tajacu) as a model.

METHODS AND RESULTS

In all, 24 adult male collared peccaries received either low- (n = 12) or high-fibre diet (n = 12) to induce contrasting gut fermentation profiles. They were submitted to three short-term challenges, allowing us to rate the animals in a coping-style dimension named 'calmness'. At the end of the experimental period, we collected samples of peccaries' forestomach contents to characterize bacterial diversity. We found a significant positive association between individual 'calmness' z-scores and the bacterial evenness index in gut bacteria (and a similar trend with the Simpson's diversity index), suggesting a more homogeneous bacterial community of calmer individuals. We also found a positive association between fibres digestibility and gut bacterial diversity in the peccaries' forestomach, but no effect of the dietary fibre level.

CONCLUSIONS

Gut bacteria evenness increases with 'calmness' z-scores, suggesting a more homogeneous bacterial community of calmer individuals, compared with the more heterogeneous of the most distressed ones. Our results also suggest associations between the digestibility of ADF with the gut bacterial diversity indices and with the relative abundance of the Actinobacteria phylum.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our data showed that the hosts' individual behavioural differences are potentially aligned with gut bacterial diversity. The behaviour-microbiota link is correlated with host feed efficiency and, ultimately, may have implications for animal health and welfare of farm animals.

A Preliminary Investigation of Social Network Analysis Applied to Dairy Cow Behavior in Automatic Milking System Environments

Simple Summary

Cows are social animals, therefore understanding the ways that they interact can help improve their management and welfare. We used social network analysis (SNA) to data on voluntary cow movement through a sort gate in an automatic milking system to identify pairs of cows that repeatedly passed through a sort gate in close succession (affinity pairs). Results from this exploratory study showed that when cows were separated from their affinity-pair cow the day-day variability in milk production increased by a factor of 3, a possible indicator of stress. The results of this exploratory study suggest that SNA could be used as a tool to better understand the social dynamics of dairy cows and inform group and regrouping process to produce positive outcomes.

Abstract

We have applied social network analysis (SNA) to data on voluntary cow movement through a sort gate in an automatic milking system to identify pairs of cows that repeatedly passed through a sort gate in close succession (affinity pairs). The SNA was applied to social groups defined by four pens on a dairy farm, each served by an automatic milking system (AMS). Each pen was equipped with an automatic sorting gate that identified when cows voluntarily moved from the resting area to either milking or feeding areas. The aim of this study was two-fold: to determine if SNA could identify affinity pairs and to determine if milk production was affected when affinity pairs where broken. Cow traffic and milking performance data from a commercial guided-flow AMS dairy farm were used. Average number of milked cows was 214 ± 34, distributed in four AMS over 1 year. The SNA was able to identify clear affinity pairs and showed when these pairings were formed and broken as cows entered and left the social group (pen). The trend in all four pens was toward higher-than-expected milk production during periods of affinity. Moreover, we found that when affinities were broken (separation of cow pairs) the day-to-day variability in milk production was three times higher than for cows in an affinity pair. The results of this exploratory study suggest that SNA could be potentially used as a tool to reduce milk yield variation and better understand the social dynamics of dairy cows supporting management and welfare decisions.