Brain activity reflects (chronic) welfare state: Evidence from individual electroencephalography profiles in an animal model

Open-source software utilization for zebrafish embryos behavior test

This work described simple methods for measuring locomotive activity using open-source software, ImageJ1.54fFiji, and VirtualDub2. The significance of animal behavior is a mirror of brain activity, which can give information implicated with neurological diseases. Commercial behavioral analysis software frequently needs expertise and expenses high costs due to equip a specific instrument to use of software, thereby encouraging a trend toward open-source alternatives that are both accessible and effective. Here, we explained how to convert video format, measure movement, and produce useful locomotive parameters to aid in the assessment of zebrafish embryos. This method could be easily translated for use in other model systems. This methodology seeks to streamline behavioral quantification in research contexts, encouraging broader research aspects.

Differences between facilities in horse welfare profiles: slight differences in management/working conditions may be enough

Many studies focus on animal welfare in terms of specific, either behavioural or physiological, indicators or on the impact of a particular management factor. However, an animal's welfare state results from the individual's perception of its general environment, which has consequences at both behavioural and physiological levels. Previous research on horses has shown that different riding schools could be characterised by different emotional/cognitive profiles of horses, in relation sometimes with one single management factor. In the present study, we aimed at determining if such facility-specific horse profiles could also be found in terms of welfare, i.e. facility-specific "welfare profiles", using a multifaceted approach where animals' welfare state was assessed based on detailed behavioural, health and physiological measurements. A total of 59 horses from three different riding schools, with a very similar global conventional management but differed slightly in terms of turn-out frequency and riding techniques were studied. A principal component analysis and statistical comparisons showed that, despite the close similarity in management between the three sites, the horses' welfare state was very different and specific to each structure. Thus, this study using behavioural, health and physiological measures, highlights the existence of facility horse welfare profiles and reveals that even apparently minor differences in management practices could have a major impact on the horses' welfare state. The quality of ridden work, which is often not taken into account in studies on horse welfare, could be a major issue.

Integrating physiology into movement ecology of large terrestrial mammals

Movement paths are influenced by external factors and depend on an individual's navigation capacity (Where to move?), motion capacity (How to move?) and are ultimately driven by internal physiological state (Why move?). Despite physiology underlying most aspects of this movement ecology framework, the physiology-movement nexus remains understudied in large terrestrial mammals. Within this Commentary, we highlight the physiological processes that underpin the movement ecology framework and how integrating physiological measurements can provide mechanistic insights that may enhance our understanding of the drivers of animal movement. We focus on large terrestrial mammals, which are well represented within the movement ecology literature but are under-represented in movement studies that integrate physiological state. Recent advances in biologging technology allow for physiological variables, such as heart rate and body movements, to be recorded remotely and continuously in free-living animals. Biologging of body temperature may provide additional insights into the physiological states driving movement. Body temperature not only provides a measure of thermal stress, but also an index of animal wellbeing through quantification of nutrition, hydration, reproductive and disease states that may drive animal movements. Integrating measures of body temperature with fine-scale GPS locations may provide insights into causality and improve our mechanistic understanding of animal movement, which is crucial for understanding population performance and monitoring reintroduction success. We recommend that baseline studies are undertaken, linking animal movement to the underlying physiological mechanisms, to allow for the development of realistic predictive models to improve conservation efforts in the Anthropocene.

Non-invasive scalp recording of electroencephalograms and evoked potentials in unanesthetized horses using a 12-channel active electrode array

Despite the long history of the horse-human bond, our understanding of the brain and mind of horses remains limited due to the lack of methods to investigate their brain functions. This study introduces a novel methodology for completely non-invasive, multi-channel recording of electroencephalography (EEG) and evoked potentials in awake horses to examine equine auditory cortical processing. The new approach utilizes specially designed brush-shaped active electrodes that facilitate stable signal acquisition through the hair coat by penetrating electrode pins and integrated pre-amplifiers. A 12-channel electrode array provided greater scalp coverage than prior work. As a proof of concept, clear cortical auditory evoked potentials (CAEPs) were recorded in response to sound onsets and offsets. The equine CAEP waveform morphology resembled the human P1-N1-P2-N2 complex, although the latencies were shorter than typical human values. The CAEP amplitudes were maximal at centroparietal electrodes, contrasting with the frontocentral distribution seen in humans, potentially explained by differences in auditory cortex orientation between species. This non-invasive multi-electrode method enables the evaluation of cognitive abilities, normal and abnormal brain functions, and advances scientific understanding of the equine mind. It offers potential widespread applications for recording EEGs and evoked potentials in awake horses and other medium-to-large mammalian species.

Animal-Assisted Interventions: Factors Affecting Donkey Behaviours and Attitude Toward Humans

The relationship between humans and donkeys has ancient origins. In recent years, donkeys' involvement in Animal-Assisted Intervention (AAI) has grown, raising major concerns about their welfare during these activities. We investigated the factors affecting donkeys' behaviour during an AAI programme for migrants. We observed an effect of human distance from the animal, the interaction mode, and food presence on the animals' behaviours and attitudes toward humans. Moreover, we provide preliminary evidence of the effect of AAI on migrants' welfare and prosocial behaviours and offer insights into the issues to address in future studies.

From Human Perception of Good Practices to Horse (Equus Caballus) Welfare: Example of Equine-Assisted Activities

Equine-assisted intervention (EAI) studies deal with clients, whereas very few studies focused on the effects on animals. EAI equids are also submitted to management, which influences their welfare. Management and working conditions depend on human decisions and perception. We gathered information through a survey about facilities managers' strategies (n = 51) and obtained direct information on management and working practices and their consequences on equids' welfare through an observational study (n = eight facilities, 174 equids). Differences in managers' perceptions of good management practices were related to the facility's involvement in EAI, e.g., increased awareness of equids' needs (housing and feeding), especially when EAI was the main activity. A detailed observational study on eight additional facilities confirmed that. Facility management profiles were paralleled by equids' welfare profiles. Clear correlates were found between management decisions and welfare consequences. One major factor influencing welfare and human-equid interactions appeared to be working modalities, with more EAI facilities practicing groundwork and bitless work. Facilities where equids were the most involved in mixed activities had the most equids with compromised welfare. Given EAI clients' particularities, conventional working modalities are less adapted and at risk of increased discomfort for equids. Overall, survey and observational approaches converged but some discrepancies (choice of equid type) appeared between the reported and observed prevalence.

Selected Acoustic Frequencies Have a Positive Impact on Behavioural and Physiological Welfare Indicators in Thoroughbred Racehorses

(1) Background: Since antiquity, it is considered that sounds influence human emotional states and health. Acoustic enrichment has also been proposed for domestic animals. However, in both humans and animals, effects vary according to the type of sound. Human studies suggest that frequencies, more than melodies, play a key role. Low and high frequencies, music tuning frequency and even EEG slow waves used for 'neurofeedback' produce effects. (2) Methods: We tested the possible impact of such pure frequencies on racehorses' behavior and physiology. A commercial non-audible acoustic stimulus, composed of an array of the above-mentioned frequencies, was broadcasted twice daily and for three weeks to 12 thoroughbred horses in their home stall. (3) Results: The results show a decrease in stereotypic behaviors and other indicators such as yawning or vacuum chewing, an increase in the time spent in recumbent resting and foraging, and better hematological measures during and after the playback phase for 4 of the 10 physiological parameters measured. (4) Conclusions: These results open new lines of research on possible ways of alleviating the stress related to housing and training conditions in racehorses and of improving physical recovery.

What drives horse success at following human-given cues? An investigation of handler familiarity and living conditions

Cues such as the human pointing gesture, gaze or proximity to an object are widely used in behavioural studies to evaluate animals' abilities to follow human-given cues. Many domestic mammals, such as horses, can follow human cues; however, factors influencing their responses are still unclear. We assessed the performance of 57 horses at a two-way choice task testing their ability to follow cues of either a familiar (N = 28) or an unfamiliar informant (N = 29). We investigated the effects of the length of the relationship between the horse and a familiar person (main caregiver), their social environment (living alone, in dyads, or in groups) and their physical environment (living in stalls/paddocks, alternating between paddocks and pastures, or living full time in pastures). We also controlled for the effects of horses' age and sex. Our results showed that horses' success rate at the task was not affected by the familiarity of the informant and did not improve with the relationship length with the familiar informant but did increase with the age of the horses. Horses living in groups had better success than the ones kept either in dyads or alone. Finally, horses housed in small paddocks had lower success than those living on pasture. These results indicate that with age, horses get better at following human-given indications regardless of who the human informant is and that an appropriate living and social environment could contribute to the development of socio-cognitive skills towards humans. Therefore, such aspects should be considered in studies evaluating animal behaviour.

Electroencephalogram and Physiological Responses as Affected by Slaughter Empathy in Goats

Recent advances in emotions and cognitive science make it imperative to assess the emotional stress in goats at the time of slaughter. The present study was envisaged to study the electroencephalogram and physiological responses as affected by slaughter empathy in goats. A total of 12 goats were divided into two groups viz., E-group (goats exposed to slaughter environment, n = 6) and S-group (goat slaughtered in front of E-group, n = 6). The electroencephalogram and physiological responses in male Boer cross goats (E-group) were recorded in a slaughterhouse in two stages viz., control (C) without exposure to the slaughter of conspecifics and treatment (T) while visualizing the slaughter of conspecifics (S—slaughter group). The exposure of the goat to the slaughter of a conspecific resulted in a heightened emotional state. It caused significant alterations in neurobiological activity as recorded with the significant changes in the EEG spectrum (beta waves (p = 0.000491), theta waves (p = 0.017), and median frequency MF or F50 (p = 0.002)). Emotional stress was also observed to significantly increase blood glucose (p = 0.031) and a non-significant (p = 0.225) increase in heart rate in goats. Thus, slaughter empathy was observed to exert a significant effect on the electric activity of neurons in the cerebrocortical area of the brain and an increase in blood glucose content.

Positive Aspects of Welfare in Sheep: Current Debates and Future Opportunities

The concept of positive welfare is an expansion of the traditional understanding that animal welfare is defined by minimizing stress, pain, suffering, and disease. Positive welfare shifts the animal welfare narrative from a focus on reducing negative experiences to proactively providing animals with opportunities to have positive experiences and feelings. The concept, although around for several decades, is in its infancy in terms of developing ways of assessing positive welfare on farms, especially in extensive systems, and there are challenges in the adoption of positive welfare practices and the monitoring of continuous improvement at the farm level. Using an iterative approach, this critical review aims to explore the extent to which positive welfare interventions and indicators are positioned and have been developed within the animal welfare literature for sheep. This paper critiques existing positive welfare indicators, such as choices in food and the physical environment, conspecific social synchronization, maternal bonds, intergenerational knowledge transfer, positive human-animal relationships, etc., as currently assessed by the 'good life framework'. It also reviews the characteristics of scientific measures for (positive) affective states in the current sheep literature and their potential contribution to understanding positive welfare states in sheep. In conclusion, this paper provides recommendations for future research regarding sheep welfare.

Animals in Animal-Assisted Services: Are They Volunteers or Professionals?

With the increasingly common practice of Animal-Assisted Services (AAS), whether in therapy, coaching, education, or volunteering programs, the concern over animal welfare has also risen. However, no standards have yet been established for good practices to ensure the animal’s mental health. This is largely due to the wide variety of roles played by animals in interventions and the lack of ‘job descriptions’ for the animal in diverse settings. Some professionals call their animal a ‘volunteer’, others mention that some directive guidance is given to the therapy animal, and some assistance animals are highly trained. Misunderstandings could be avoided if the integrated animal were to receive a justifiable label: volunteer or professional. Choosing either one comes with obligations for the owner, handler, or therapist. In this paper, we compare the roles of human volunteers and professionals to the roles of animals involved in therapy. We also demonstrate the obligations that come along with the decision to label animals as such either volunteers or professionals. Furthermore, we make a plea for animal-friendly interventions, whether in a volunteer position or as a professional, in order to stimulate the animal’s cooperation and motivation. Studying dopamine and translating the findings into context-ethograms can provide a way to judge behavior more objectively.

Quality of Life within Horse Welfare Assessment Tools: Informing Decisions for Chronically Ill and Geriatric Horses

Equine Quality of Life (QoL) is an important concern in decision making in veterinary medicine and is especially relevant for chronically ill or geriatric horses towards the end of their lives. To our knowledge, there is no currently available QoL assessment tool for chronically ill or geriatric horses that assesses equine QoL defined as the horse's evaluation of their life. However, tools exist to assess equine welfare in different contexts. Hence, the aims of this study were to analyse how equine welfare, QoL, well-being and happiness assessment tools label, define and operationalise the concepts and to discuss the tools' suitability to assess equine QoL in the context of end-of-life decisions for chronically ill or geriatric horses. Fourteen articles were found through a systematic literature search, describing ten equine welfare assessment tools and one approach to integrating equine QoL in veterinary practice that suggests QoL assessment parameters. We discuss that some welfare assessment tools have the potential to support the development of a QoL assessment tool informing decisions towards the end of horses' lives if they are adjusted to focus on the horses' experiences, to provide an integration into an overall QoL grade and are tailored to chronically ill or geriatric horses.

Laterality in Horse Training: Psychological and Physical Balance and Coordination and Strength Rather Than Straightness

Simple Summary

For centuries, straightening a horse has been considered a key element in achieving its responsiveness and suppleness and has been a traditional goal in training. However, body asymmetry (natural crookedness), motor laterality (the preference for limbs on one side) and sensory laterality (the preference for sensory organs on one side) are naturally occurring phenomena. In humans, the forced correction of these imbalances, for example, forcing left-handed children to write with their right hands, has been shown to lead to psychological imbalance. In view of this, lateral asymmetries in horses should be accepted, and training should focus on psychological and physical balance, coordination and equal strength on both sides, instead of enforcing “straightness”. To explore this, we conducted a review of the literature on motor and sensory laterality in horses and found that the evidence suggests that enforcing straightness may be stressful and may even be counterproductive by causing psychological and physical imbalance relative to a horse, making it tense and uncooperative. In general, body asymmetry has been shown to have little impact on performance, but increases in motor and sensory laterality can indicate insufficiencies in housing, handling and training. We, therefore, propose that laterality should be recognized as a welfare indicator and that straightness in a horse should be achieved by conducting training focused on balance, coordination and equal strength on both sides.

Abstract

For centuries, a goal of training in many equestrian disciplines has been to straighten the horse, which is considered a key element in achieving its responsiveness and suppleness. However, laterality is a naturally occurring phenomenon in horses and encompasses body asymmetry, motor laterality and sensory laterality. Furthermore, forcibly counterbalancing motor laterality has been considered a cause of psychological imbalance in humans. Perhaps asymmetry and laterality should rather be accepted, with a focus on training psychological and physical balance, coordination and equal strength on both sides instead of enforcing “straightness”. To explore this, we conducted a review of the literature on the function and causes of motor and sensory laterality in horses, especially in horses when trained on the ground or under a rider. The literature reveals that body asymmetry is innate but does not prevent the horse from performing at a high level under a rider. Motor laterality is equally distributed in feral horses, while in domestic horses, age, breed, training and carrying a rider may cause left leg preferences. Most horses initially observe novel persons and potentially threatening objects or situations with their left sensory organs. Pronounced preferences for the use of left sensory organs or limbs indicate that the horse is experiencing increased emotionality or stress, and long-term insufficiencies in welfare, housing or training may result in left shifts in motor and sensory laterality and pessimistic mentalities. Therefore, increasing laterality can be regarded as an indicator for insufficiencies in housing, handling and training. We propose that laterality be recognized as a welfare indicator and that straightening the horse should be achieved by conducting training focused on balance, coordination and equal strength on both sides.

Detecting Welfare in a Non-Verbal Species: Social/Cultural Biases and Difficulties in Horse Welfare Assessment

Simple Summary

There is a paradox about the welfare of horses in the domestic situation: on the one hand, horses are beloved partners for most owners, but on the other hand, scientific studies are converging to show that there is a high prevalence of welfare problems. There seems to be a mismatch between theoretical knowledge and field applications. In this review, we aim at disentangling the possible factors explaining such a paradox. Among them, we consider the impact of anthropomorphic and cultural biases, popular beliefs, but also overexposure to horses with compromised welfare state, which can change owners’ representation of what is a “normal” horse, on the undervaluation of horse welfare state. We suggest that, rather than simply having knowledge on what should be done, identifying the horse welfare state using validated animal-based indicators is essential to identify and promote best practices.

Abstract

Horses were domesticated for more than 5000 years and have been one of the most emblematic species living alongside humans. This long-shared history would suggest that horses are well known and well understood, but scientific data raise many concerns about the welfare state of most domestic horses suggesting that many aspects have been largely misunderstood. In the present review, we will examine some of the possible human factors that may explain the huge prevalence of welfare problems, despite horses being of special importance to humans. First of all, as horses are non-verbal, current management practices rely upon what one thinks is good for them, which opens the way to subjective interpretations and projections, based on one’s own subjective experience but probably still more on cultural/social norms and influences, traditions and beliefs. The lack of recognition, identification, or even the misinterpretation of signals are other potential reasons for welfare issues. Lastly, the over-exposure to animals with expressions of compromised welfare may lead to lower sensitivity of owners/professionals. That is why we lastly suggest that instead of simply providing information on what to do, we should promote validated visible indicators that leave less room for personal interpretation.

Basic Needs in Horses?-A Literature Review

Simple Summary

All animals have requirements that are essential for their welfare, and when these basic needs are not met, the animal suffers. In horses, it is claimed that these needs include social contact, social companionship, free movement and access to roughage in the form of grass, hay and/or straw. To validate this claim, this review examines 38 studies that reported on horses’ responses when one or more of these factors are restricted. We categorised the type of responses investigated: (a) Stress (e.g., increased stress hormones), (b) Active (e.g., increased aggression), (c) Passive (e.g., depressive-like behaviour) and (d) Abnormal Behaviour (e.g., stereotypies), and analysed the frequencies with which the investigated responses were shown. Overall, the studies reported that horses did react to restrictions in the described basic needs, especially to combinations of restricted social contact, free movement and access to roughage. The observation of passive responses and the development of abnormal behaviour provided compelling evidence that horses were suffering under these restrictions, and existing abnormal behaviours indicated that they had suffered at some time in the past. We conclude that the literature supports the claim that social contact, free movement and access to roughage are basic needs in horses and need to be taken into consideration to ensure their mental and physical welfare in management and training.

Abstract

Every animal species has particular environmental requirements that are essential for its welfare, and when these so-called “basic needs” are not fulfilled, the animals suffer. The basic needs of horses have been claimed to be social contact, social companionship, free movement and access to roughage. To assess whether horses suffer when one or more of the four proposed basic needs are restricted, we examined several studies (n = 38) that reported behavioural and physiological reactions to these restrictions. We assigned the studies according to the four types of responses investigated: (a) Stress, (b) Active, (c) Passive, and (d) Abnormal Behaviour. Furthermore, the number of studies indicating that horses reacted to the restrictions were compared with the number of studies reporting no reaction. The limited number of studies available on single management restrictions did not allow conclusions to be drawn on the effect of each restriction separately, especially in the case of social companionship. However, when combinations of social contact, free movement and access to roughage were restricted, many of the horses had developed responses consistent with suffering. Passive Responses, indicating acute suffering, and Abnormal Behaviour, indicating suffering currently or at some time in the past, were especially clearly demonstrated. This provides further evidence of the usefulness of assessing behavioural parameters in combination with physiological measurements when evaluating horse welfare. This meta-analysis of the literature confirms that it is justified to claim that social contact, free movement and access to roughage are basic needs in horses.