Horses Working in Therapeutic Riding Programs: Cortisol, Adrenocorticotropic Hormone, Glucose, and Behavior Stress Indicators

Behavioral and physiological responses of horses to ground-based adaptive horsemanship lessons for veterans with post-traumatic stress disorder (PTSD)

Little literature exists on horses in adaptive horsemanship (AH) despite concerns about their well-being. The study objective was to evaluate behavioral and physiological responses of horses to ground-based AH lessons for veterans with post-traumatic stress disorder (PTSD). Lessons were expected to alter horses' hormone concentrations, behavior, and muscle activity. Geldings were assigned to AH (n=6; 20.3 ± 1.9 yrs., mean ± SE) or control (CON; stall in arena, n=6; 13.8 ± 1.7 yrs.) conditions for 8-week sessions based on current occupation (AH = equine-assisted services; CON = recreational riding). Plasma cortisol, epinephrine, norepinephrine, and oxytocin concentrations from samples at 0 (start of lesson), 3, 5, 25, and 30 (end) min were determined using assays validated in horses. Surface electromyography (sEMG) (masseter and brachiocephalic; Noraxon, Scottsdale, AZ, USA) and video were recorded continuously. Average rectified values (ARV) and median frequency (MF) were calculated (100 ms) after sEMG data were normalized, rectified, and filtered. The number, number of unique, and duration of stress related behaviors (ethogram) were recorded by three trained (ĸ ≥ 0.7) observers. Data were analyzed with repeated measures ANOVAs (significance P ≤ 0.05) with fixed effects of treatment, time point, week, and their interactions as appropriate and random effect of horse. CON horses had elevated cortisol concentrations (P = 0.0023) at 25 and 30 min. AH horses displayed fewer (P ≤ 0.0491) stress related and unique behaviors. CON horses were described as more (P < 0.0001) anxious, nervous, and stressed than AH horses (calm, comfortable, patient, and relaxed) in qualitative behavior analysis (22 observers). AH horses were less stressed than CON horses.

Factors affecting measurement of basal adrenocorticotropic hormone in adult domestic equids: A scoping review

Measurement of basal adrenocorticotropic hormone (ACTH) concentration is the most commonly used diagnostic test for pituitary pars intermedia dysfunction (PPID). Although several pre-analytical and analytical factors have been reported to affect basal ACTH concentrations in equids, the extent to which these have been evaluated in the context of PPID diagnosis is unclear. The objectives of this scoping review were to identify and systematically chart current evidence about pre-analytical and analytical factors affecting basal ACTH concentrations in adult domestic equids. Systematic searches of electronic databases and conference proceedings were undertaken in June 2022, repeated in October 2022 and updated in August 2023. English language publications published prior to these dates were included. Screening and data extraction were undertaken individually by the authors, using predefined criteria and a modified scoping review data extraction template. After removal of duplicates, 903 publications were identified, of which 235 abstracts were screened for eligibility and 134 publications met inclusion criteria. Time of year, exercise, breed/type and transportation were the factors most frequently associated with significant increases in ACTH concentration (n = 26, 16, 13 and 10 publications, respectively). Only 25 publications reported inclusion of PPID cases in the study population, therefore the relationship between many factors affecting basal ACTH concentration and diagnostic accuracy for PPID remains undefined. However, several factors were identified that could impact interpretation of basal ACTH results. Findings also highlight the need for detailed reporting of pre-analytical and analytical conditions in future research to facilitate translation of evidence to practice.

Characterizing stress during animal interaction: a focus on the human endocrine response during equine-assisted services

Repeated stresses applied to the rider may contribute to the documented physical and psychosocial outcomes from equine-assisted services. In this brief review, a summary of neuroendocrine markers of stress, including immunoglobulin A, serotonin, cortisol, progesterone, and oxytocin, is presented within the context of the physiology of stress modulation. Results are mixed with regard to the effects of these hormones on rider physiology before, during, and after equine-assisted services. However, some results from existing studies are promising with regard to the attenuation of stress. Future research should include a cross-disciplinary approach when conducting well-controlled studies with proper treatment and experimental fidelity, while also considering exogenous and endogenous factors that influence rider physiology.

The effect of training load stress on salivary cortisol concentrations, health parameters and hematological parameters in horses

The performance of sport horses is conditioned not only by the quality of its gene pool, but also by a large number of external factors. The most dominant being nutrition, quality of breeding, level of zootechnical care and the quality of the sports rider and coach. Important factor is the process of individuals' adaptation to the training load occurring during the training itself. This study was focused on the analysis of salivary cortisol levels as well as hematological and biochemical blood parameters in relation to load to which the tested horses were subjected. In the study 14 horses of sport breeds were analyzed a all tested horses were in the same (medium) level of training load. Tested horses underwent following stages of workload - transportation, jumping training, parkour competition, treadmill training, riding training, shoeing and lunging of various intensity. Saliva samples were obtained using a tampon on a string which was inserted into horse's oral cavity, chewed by the horse and placed in a sterile tube with a closable lid. Afterwards, the samples were then stored in deep-freezing boxes at temperature of -80 °C. The EIA cortisol kit was used in this study. The absorbance was read at the wavelength of 450 nm against a reference wavelength of 620-630 nm or a blank sample. Blood samples were obtained at the beginning of the experiment, after half a year of running the experiment and at the end of the experiment from v. jugularis. Hematological analysis were carried out using automatic hematologic analyser and multiple parameters were observed. Analysis of biochemical parameters in blood serum were realized using commercial DiaSys kits and semiautomatic biochemical spectrophotometer. Sodium, potassium and chlorides were measured using automatic analyzer EasyLytePlus. In all monitored forms of exercise (transportation, jumping training, parkour competition, treadmill training, riding training, horse shoeing, lunging), an increase in cortisol concentrations immediately after the exercise was recorded, but only spotted statistically significant differences were found during the transportation of monitored horses. The levels of blood parameters were within the reference range during the experiment period. From a comprehensive evaluation of the results, it can be stated that there were no visible health changes to the horses that underwent the experimental load and that manipulation with horses is an important factor that has effect on horses' stress response. In general, the results of this study show no visible impact of training and/or load on the health status of horses over entire 12-month duration of the experiment.

Equids in Equine Assisted Services: A Scoping Review

Equid welfare in equine assisted services (EAS) is an area that has received attention, but less attention than the documentation of human outcomes in response to EAS. To safeguard the well-being of equids and minimize human risk of injury, continued research on the effects of EAS programming and participants on equids needs to occur. The aims of this systematic scoping review were to identify the approaches taken for describing and understanding equids in EAS and the methods employed in evaluating equids' responses to EAS programming, participants, or both. Literature searches were performed in relevant databases to identify titles and abstracts for screening. Fifty-three articles were identified for full-text review. Fifty-one articles met the inclusion criteria and were retained for information and data extraction. The qualitative grouping of articles by study aim resulted in four categories: 1) characterization and description of equids in EAS; 2) the acute responses of equids to EAS programming, participants, or both; 3) the effects of management practices; and 4) the chronic responses of equids to EAS programming and participants. The latter three areas are in need of more research, especially as it relates to differentiating acute and chronic effects of EAS on the equids involved. Detailed reporting of information on study design, programming and participant characteristics, equid demographics, and workload are needed to facilitate comparison among studies and permit eventual meta-analysis of studies. Multi-faceted approaches including an array of measurements as well as relevant and informative control groups or conditions are required to identify the complex effects of EAS work on equids, their welfare, well-being, and affective states.

Sense of Coherence and Self-Rated Aggression of Adolescents during the First Wave of the COVID-19 Pandemic, with a Focus on the Effects of Animal Assisted Activities

The COVID-19 pandemic has caused extreme deviations from everyday life. The aim of this study was to investigate how these deviations affected adolescents' sense of coherence and their level of aggression, and whether this was influenced by their relationship with animals, especially horses. In two random samples of students from vocational schools in Hungary, taken in June 2018 and June 2020 (n1 = 525, n2 = 412), separate groups were drawn from those who had regularly engaged in equine-assisted activities (ES) and those who had not (OS) before the pandemic. Data were collected using an anonymous, paper-based questionnaire, and during the pandemic an online version of the Sense of Coherence (SOC13) and Bryant-Smith (B12) scales. During the pandemic, boys' sense of coherence weakened and their aggressiveness increased. Multiple linear regression analyses showed that, regardless of gender and age group, increased time spent using the internet (p < 0.001), a lack of classmates (p = 0.017), reduced time spent outdoors (p = 0.026) and reduced physical activity (p < 0.038) during the pandemic significantly increased the tendency for aggressive behavior, whereas being with a horse or pet was beneficial (p < 0.001). The changes imposed by the curfew were rated as bad by 90% of the pupils, however, those with a strong sense of coherence felt less negatively about them. Schools should place a great emphasis on strengthening the students' sense of coherence.

Nociceptive pain and anxiety in equines: Physiological and behavioral alterations

Pain and anxiety are two of the most important concerns in clinical veterinary medicine because they arise as consequences of multiple factors that can severely affect animal welfare. The aim of the present review was to provide a description and interpretation of the physiological and behavioral alterations associated with pain and anxiety in equines. To this end, we conducted an extensive review of diverse sources on the topic. The article begins by describing the neurophysiological pathway of pain, followed by a discussion of the importance of the limbic system in responses to pain and anxiety, since prolonged exposure to situations that cause stress and pain generates such physiological changes as tachycardia, tachypnea, hypertension, hyperthermia, and heart rate variability (HRV), often accompanied by altered emotional states, deficient rest, and even aggressiveness. In the long term, animals may show deficiencies in their ability to deal with changes in the environment due to alterations in the functioning of their immune, nervous, and endocrinologic systems. In conclusion, pain and anxiety directly impact the homeostasis of organisms, so it is necessary to conduct objective evaluations of both sensations using behavioral scales, like the horse grimace scale, complemented by assessments of blood biomarkers to analyze their correlation with physiological parameters: Heart rate, respiratory rate, HRV, theparasympathetic tone activity index, lactate and glucose levels, and temperature. Additional tools - infrared thermography, for example - can also be used in these efforts to improve the quality of life and welfare of horses.

Emotion Recognition in Horses with Convolutional Neural Networks

Creating intelligent systems capable of recognizing emotions is a difficult task, especially when looking at emotions in animals. This paper describes the process of designing a “proof of concept” system to recognize emotions in horses. This system is formed by two elements, a detector and a model. The detector is a fast region-based convolutional neural network that detects horses in an image. The model is a convolutional neural network that predicts the emotions of those horses. These two elements were trained with multiple images of horses until they achieved high accuracy in their tasks. In total, 400 images of horses were collected and labeled to train both the detector and the model while 40 were used to test the system. Once the two components were validated, they were combined into a testable system that would detect equine emotions based on established behavioral ethograms indicating emotional affect through the head, neck, ear, muzzle, and eye position. The system showed an accuracy of 80% on the validation set and 65% on the test set, demonstrating that it is possible to predict emotions in animals using autonomous intelligent systems. Such a system has multiple applications including further studies in the growing field of animal emotions as well as in the veterinary field to determine the physical welfare of horses or other livestock.

Interest in Humans: Comparisons between Riding School Lesson Equids and Assisted-Intervention Equids

Simple Summary

Very little is known about the impact of equine-assisted interventions on equids’ perception of humans. Different factors can influence human–horse relationships: animal characteristics, daily interactions with the caretakers, and working and living conditions. In this study, 172 equids working in equine-assisted interventions, ‘classical’ riding school lessons, or both were submitted to a standardised human–horse relationship test in order to test if EAI had an impact on the equid reactions to humans. The possible influence of intrinsic (age, sex, type) or other extrinsic factors (housing and feeding conditions) was also considered. The results showed that the number (more than the type) of experimenter-directed behaviours varied significantly between individuals and that the activity was the most important factor of influence: Equids working in riding school lessons performed more interactive behaviours than those working in equine-assisted interventions or having mixed activity. Other factors such as daily hay quantity, the horses’ age, and sex also influenced secondarily the horse’s motivation to interact, although no interaction was found between factors. These results suggest that equine-assisted interventions do influence horses’ perception of humans outside work. Further studies are needed in order to understand the processes involved.

Abstract

Little is known about the impact of equine-assisted interventions (EAI) on equids’ perception of humans. In this study 172 equids, living in 12 riding centres, were submitted to a standardised human–horse relationship test: the motionless person test. Age, sex, type (horse/pony), housing, and feeding conditions of subjects were recorded. Overall, 17 equids worked in EAI, 95 in riding school lessons (RS), and 60 in both (EAI-RS). There were high inter-individual variations in the number of interactive behaviours directed towards the experimenter: negative binomial general linear models showed that activity was the most important factor: RS equids performed more interactive behaviours than EAI (p = 0.039) and EAI-RS (p < 0.001) equids. Daily quantity of hay appeared as the second most important factor (equids with more than 3 kg interacted more than equids with less than 3 kg, p = 0.013). Individual characteristics were also important as horses interacted more than ponies (p = 0.009), geldings more than mares (p = 0.032), and 3–15-year-old equids more than equids over 15 years (p = 0.032). However, there was no interaction between factors. The lower number of interactive behaviours of EAI equids leads to different hypotheses—namely, selection on temperament, specific training, or compromised welfare (apathy). In any case, our results raised new lines of questions on EAI.

A Commentary on the Contemporary Issues Confronting Animal Assisted and Equine Assisted Interactions

The field of human-animal interactions and, more specifically, animal-assisted interventions and equine assisted interactions (equine assisted interactions have significantly evolved over the past half century. The primary purpose of this paper is to provide a brief commentary of both fields and the challenges they are presently experiencing as they move forward in their future. More specifically within this commentary, attention will be given to highlighting some of the directions taken in both fields, including clarifying their terminology as it applies to scope of practices, trends in research and practice, the need to emphasize the welfare of the animals as well as the possible directions to standardized professional competencies and the needed professional development.

Effectiveness of animal-assisted interventions for children and adults with post-traumatic stress disorder symptoms: a systematic review and meta-analysis

Background: Animal-assisted interventions (AAI) are increasingly applied for people with post-traumatic stress disorder (PTSD) symptoms albeit its effectiveness is unclear.Objectives: To examine the effectiveness of AAI for treating PTSD symptoms.Method: We searched 11 major electronic databases for studies reporting quantitative data on effects of AAI for children and adults with PTSD symptoms. Of 22'211 records identified, we included 41 studies with 1111 participants in the systematic review comprising eight controlled studies with 469 participants in the meta-analysis. We conducted random-effects meta-analyses with all controlled studies based on standardized mean differences (SMD), and calculated standardized mean change (SMC) as effect sizes for studies with a pre-post one-group design. Two independent researchers assessed the quality of the included studies using the NIH Study Quality Assessment Tools. The primary outcome was PTSD or depression symptom severity measured via a standardized measurement at pre- and post-intervention assessments.Results: There was a small but not statistically significant superiority of AAI over standard PTSD psychotherapy (SMD = -0.26, 95% CI: -0.56 to 0.04) in reducing PTSD symptom severity while AAI was superior to waitlist (SMD = -0.82, 95% CI: -1.56 to 0.08). Getting a service dog was superior to waiting for a service dog (SMD = -0.58, 95% CI: -0.88 to -0.28). AAI led to comparable effects in reducing depression as standard PTSD psychotherapy (SMD = -0.03, CI: -0.88 to 0.83). Pre-post comparisons showed large variation for the reduction in PTSD symptom severity, with SMCs ranging from -0.38 to -1.64, and for depression symptom severity, ranging from 0.01 to -2.76. Getting a service dog lowered PTSD symptoms between -0.43 and -1.10 and depression with medium effect size of -0.74.Conclusions: The results indicate that AAI are efficacious in reducing PTSD symptomatology and depression. Future studies with robust study designs and large samples are needed for valid conclusions.

Age-Related Changes in the Behaviour of Domestic Horses as Reported by Owners

Simple Summary

Some treatments for common problem behaviours in domestic horses can compromise horse welfare. Such behaviours can be the manifestation of pain, confusion and conflict. In contrast, among the desirable attributes in horses, boldness and independence are two important behavioural traits that affect the fearfulness, assertiveness and sociability of horses when interacting with their environment, objects, conspecifics and humans. Shy and socially dependent horses are generally more difficult to manage and train than their bold and independent counterparts. Previous studies have shown how certain basic temperament traits predict the behavioural output of horses, but few have investigated how the age of the horse and the age it was when started being trained under saddle affect behaviour. Using 1940 responses to the Equine Behaviour Assessment and Research Questionnaire (E-BARQ), the current study explored the behavioural evidence of boldness and independence in horses and how these related to the age of the horse. Results revealed age-related effects on boldness and independence of horses. Older horses were bolder than younger horses, but horses started under saddle at an older age were less bold and independent than those started at a younger age. Additionally, significant differences in boldness and independence relating to specific breeds and primary equestrian disciplines also emerged. Finally, riders with eight or more years of riding experience reported having more independent horses than those who had ridden their whole lives. Understanding how horses’ ages affect behavioural traits can improve horse–rider matching and potentially also optimise welfare.

Abstract

The broad traits of boldness and independence in domestic horses can affect their usefulness and, indirectly, their welfare. The objective of the current study was to explore associations between attributes that reflect equine boldness and independence with both the age of horses and the age at which they were started under saddle, as well as other variables including breed, colour and primary equestrian discipline. All data were sourced from responses (n = 1940) to the 97-question online Equine Behaviour Assessment and Research Questionnaire (E-BARQ). Twenty E-BARQ items from the dataset were selected to reflect boldness and independence and were tested for univariate significance at p < 0.2. Multivariable modelling of the effect of age on remaining traits was assessed by an ordinal logistic regression, using a cumulative log odds model. This revealed that older horses were bolder (p = 0.012). However, horses started under saddle at an older age were less bold and less independent (p = 0.040 and p = 0.010, respectively). Australian Stock Horses were bolder and more independent (p = 0.014 and p = 0.007, respectively) than crossbreed horses. Horses used for breeding conformation (p = 0.039), working equitation (p = 0.045), eventing (p = 0.044) and traditional working horses (p = 0.034) were bolder than those used for other disciplines. Dressage (p = 0.039) and therapy (p = 0.040) horses were less bold than horses used for other disciplines. Stallions were bolder (p = −0.034) than geldings. Brown (p = 0.049) and chestnut (p = 0.027) horses were less bold than bay horses. Compared to crossbreed horses, Thoroughbreds (p = 0.000) and companion horses (p = 0.017) were less bold whilst heavy horses (p = 0.029) and ponies (p = 0.044) were bolder. Compared to pleasure horses, mounted games horses (p = 0.033) were less independent whereas working equitation horses (p = 0.020) were more independent. Riders with more than eight years’ experience reported more independence in their horses (p = 0.015) than those who had ridden their whole lives. The study findings suggest that boldness and independence are separate traits and only boldness was associated with the age of the horse. Factors that relate to desirable boldness and independence are important in ridden horses because they can affect rider safety. Results from this study should improve horse–rider matching and thereby potentially enhance horse welfare.

Evaluating Stress in Riding Horses: Part One-Behavior Assessment and Serum Cortisol

Stress can impact the health and well-being of animals negatively. Behavioral and physiological changes, particularly serum cortisol, offer objective and easy-to-use methods of evaluating stress in horses. However, limited studies support a positive relationship between changes in stress-related serum cortisol concentrations and stress-related behaviors in horses. This study assessed differences in stress-related behaviors and serum cortisol concentrations in horses used in a therapeutic riding program (TRH) or university riding program (UNI). Riders were grouped by disability type (TRH) or by experience level (UNI) to determine equine stress impacts. Two trained observers evaluated equine behavior during multiple riding lessons. Behaviors were scored live and via video to assess the accuracy of live scoring. Blood samples for serum cortisol concentrations were collected before, immediately after, and 30 minutes after riding lessons. Serum cortisol concentrations decreased from before to after a riding lesson (TRH, P ≤ .01; UNI, P = .0004) and increased over the course of the study (TRH ≤ 0.0002; UNI, P ≤ .0001). All serum cortisol concentrations remained within or below normal ranges. Overall behavior scores were relatively low in horses participating in both riding programs. Similar behavior scores were observed in horses ridden by novice and experienced riders (P ≥ .1662); however, behavior scores differed in TRH horses ridden by one group of disabled riders during a riding lesson (P ≤ .0431). A relationship between stress-related behavior and cortisol concentration changes was not shown clearly, but data suggest that horses were in a low-stress environment.

Effect of Human Attachment Style on Horse Behaviour and Physiology during Equine-Assisted Activities-A Pilot Study

Equine-assisted activities (EAA) for human well-being and health rely on human-horse interactions for therapeutic effect. At-risk participants with mental and emotional difficulties can show poor social skills and functioning relationships, potentially leading to unsuccessful human-horse interaction in EAA. This study addresses the effect of the attachment style (AS) of at-risk adolescents on horse physiology and behaviour during an equine-facilitated learning (EFL) program. Thirty-three adolescents participated in a 10-week EFL program with nine therapy horses (the same therapy horse per adolescent throughout the program). Adolescent AS was categorized into secure (n = 7), preoccupied (n = 11), dismissing (n = 1), or fearful (n = 12) using an Experiences in Close Relationships - Relationship Structure questionnaire. Horse heart rate (HR) and behaviour (affiliative and avoidance behaviours) in response to adolescents were recorded during grooming and riding. Over time, horses with fearful AS adolescents showed consistently more affiliative behaviours compared to those with preoccupied AS adolescents during grooming, and more constant HR and avoidance behaviours compared to those with secure AS adolescents during riding. These results suggest that a more predictable and less stressful physiological and behavioural response of therapy horses toward participants in EAA with emotional and behavioural difficulties can be mediated by a human insecure attachment style.

The State of Animal-Assisted Interventions: Addressing the Contemporary Issues that will Shape the Future

As the worldwide popularity of animal-assisted interventions (AAIs) increases, the fieldis quickly approaching a paradigm shift, adjusting its image to incorporate more evidence-basedresearch and aligning its purpose for advancing a new future. Contemporary critical issues thatconfront the field today include, but are not limited, to research, animal welfare, practice guidelines,and public policy. This article will provide an overview of the history of AAI and the majormilestones that the field has undergone. The current state of AAI research will be scrutinized, andthe areas that warrant further study will be recommended. Special attention will be given to thecurrent state of animal welfare in AAI, the research that has been done in the area, and practiceguidelines that safeguard animal wellbeing. This article will then discuss how evidence-basedresearch and animal welfare guidelines inform the development of comprehensive professionalstandards and influence changes in public policy regarding AAI. The authors' perceptions for thefield's future trajectory will be presented, which will include solutions to move the field in thedirection that best advances the human-animal bond in research, practice, and public perception.

Equine Activities Influence Horses' Responses to Different Stimuli: Could This Have an Impact on Equine Welfare?

Simple Summary

Horses are required to perform a wide variety of activities. Training a horse for these activities may influence the horse’s perception of and reactions to different stimuli. This study investigated the reactivity and emotional responses of horses involved by humans in different equine activities (dressage, jumping, eventing and equine-assisted activity/therapy) by studying their physiological and behavioral responses to different stimuli. A test setting with five phases was created to test equine responses to five different stimuli and compare these responses among horses from the different disciplines. It was demonstrated that the horses involved in the different activities had different responses, both physiologically and behaviorally, to the studied stimuli. These findings suggest that training a horse for a specific activity modifies the perception of stimuli and the strategies that the horse uses to balance its emotional state. Thus, horses involved in different activities probably behave differently according to their training. Such information is of great importance in improving training methods, with the aim of increasing equine welfare.

Abstract

The learning and cognitive challenges that horses may face differ according to the activities in which they are involved. The aim of this investigation was to study the influence of equine activities on the behavioral responses and autonomic nervous system (ANS) activity of adult horses. Forty-one horses were divided into four groups: dressage (9), jumping (10), eventing (13) and equine-assisted activity/therapy (9). A test was created to compare the horses’ behavioral and physiological responses to different stimuli. The goal was always to obtain a treat. To study the ANS activity, heart rate variability was assessed using the standard deviation of the R-R intervals (SDNN), square root of the mean of the sum of the squares of differences between successive interbeat-intervals (RMSSD) and low frequency/high frequency (LF/HF). To assess behavioral responses, video analysis was performed considering the following behaviors: exploration, interactions with another horse, and latency to approach. Significant differences in SDNN (DF = 3; F = 3.36; p = 0.0202), RMSSD (DF = 3; F = 4.09; p = 0.0078), LF/HF (DF = 3; F = 4.79; p = 0.0031), exploration (DF = 3; F = 5.79; p = 0.0013) and latency to approach (DF = 3; F = 8.97; p < 0.0001) were found among horses from different equine activities. The activity that adult horses practice appears to influence behavioral and physiological responses to different stimuli, thus impacting equine welfare.

A One Health Research Framework for Animal-Assisted Interventions

BACKGROUND

The integration of animals into healthcare, referred to as animal-assisted intervention, is a rapidly growing research field and was previously related to One Health. However, the assessment of synergistic effects of animal-assisted interventions (AAI) has been poorly addressed to date.

METHOD

We discuss experiences in integrated human and animal assessments in AAI and provide a methodical framework for One Health approaches in AAI research. We propose theoretical consideration of an integrated human and animal health assessment, as well as the use of such an integrated approach in research. Based on the existing research, we argue that, for a deeper understanding of AAI mechanisms, parallel research designs are needed.

RESULTS AND CONCLUSION

Our paper shows that a One Health study design is necessary to ensure that a tradeoff in health of animals is prevented and that an added value, or synergistic benefit, can be achieved on both sides during animal-assisted interventions.

Describing the Use of Animals in Animal-Assisted Intervention Research

Currently, there has been growing attention to animal welfare in animal-assisted interventions (AAI). However, there is a lack of scrutiny regarding what steps to take to ensure animal wellbeing during AAI research. The Institutional Animal Care and Use Committee (IACUC) reviews, monitors, and approves all research involving animal subjects in order to ensure an animal's ethical and humane treatment. However, AAI publications rarely report IACUC approval. The purpose of this critical review was to determine the frequency of IACUC approval and to report the descriptions of animal use in AAI research publications. In the 139 articles reviewed, 14 (10%) studies reported attaining IACUC approval; 4/139 (3%) reported an adverse outcome on at least one animal used in the study. The publications inconsistently reported the training or certification and veterinary care of the animals. Lacking IACUC approval in AAI studies indicates that the field underutilizes this method of monitoring animal health and welfare. The IACUC should assess, approve, and monitor research protocols involving animals prior to conducting every study to safeguard AAI animal welfare.

The Effects of Equine Assisted Therapy on Plasma Cortisol and Oxytocin Concentrations and Heart Rate Variability in Horses and Measures of Symptoms of Post-Traumatic Stress Disorder in Veterans

With the increase in the number of horses being used in Equine-Assisted Activities and Therapies (EAAT) programs and with the increasing concern for animal welfare, it is important to understand the impact of such interventions on the stress level and quality of life for the horses involved. The purpose of the present pilot study was to test the hypothesis that participation in EAAT would acutely alter physiological markers of stress and well-being, including plasma cortisol, plasma oxytocin, and heart rate variability (HRV), in horses and that symptoms of posttraumatic stress disorder (PTSD) would be reduced after five sessions of EAAT in veterans who had previously been diagnosed with PTSD. Nine healthy geldings, of various breeds, ages 10-23 years, conditioned and experienced as therapeutic riding horses, were selected to participate in the study. Of these, seven were selected at random to wear electrocardiogram units, and all nine were used for blood sampling to measure plasma cortisol and oxytocin. Each horse was randomly assigned to partner with a veteran for five EAAT sessions, 1 hour in duration. A standing control was conducted on a later date on which horses did not participate in EAAT. Measurement after 5 days of EAAT was conducted immediately after the end of the last session on day 5 using the Brief Symptom Inventory and the PCL-5 (a 20 item self-report measure of the Diagnostic and Statistical Manual of Mental Disorders - 5 for symptoms of PTSD). Two way repeated measure analysis of variance showed no significant day by time interactions for plasma cortisol (P = .821) or oxytocin (P = .861). There was a significant day by time interaction (P = .006) for heart rate (HR); where on day 1, HR (bpm) was significantly lower during the interaction with the veterans. There were no significant differences in HRV variables. Posttherapy measures in PTSD symptoms in veterans were significantly reduced except for interpersonal sensitivity (P = .08) and phobic anxiety (P = .17). There was an effect of EAAT on HR which was significantly reduced on day 2 during the actual EAAT session. Equine-Assisted Activities and Therapies had no effect on respiration rate and systolic or diastolic blood pressure in veterans involved in five sessions of EAAT, lasting 60 minutes in duration over the course of 5 days. Stress levels, as demonstrated by plasma cortisol concentrations and HRV, did not change in horses involved in EAAT sessions with veterans who had been previously diagnosed with PTSD. Furthermore, the horses used in this study did not demonstrate increased levels of well-being as demonstrated by the lack of change in plasma oxytocin concentrations after EAAT sessions. Symptoms of PTSD did change significantly in the veterans who participated in this study.

Equine Assisted Interventions (EAIs): Methodological Considerations for Stress Assessment in Horses

Equine assisted interventions (EAIs) are recently facing an increasing popularity, and are characterized by a wide diversity of practices. However, information on the welfare of animals involved in this kind of activity is often lacking. Horses are highly susceptible to work stressors related to physical constraints and/or to the need to control emotions while interacting with humans. Considerations of the emotional state of horses involved in EAIs have multiple valences: for the safety of humans and animals involved, for the quality and efficacy of interventions, as well as for ethical reasons. The aim of this unsystematic narrative review is to summarize the different approaches used for the evaluation of horses' stress responses, investigate their application in the context of EAIs, and discuss some methodological considerations for researchers and practitioners involved in EAI. The sources of information are mostly based on electronic databases (i.e., Medline, Scopus and Google scholar), as well as on hand searches of the references of retrieved literature, and discussions with experts in the field. At present, a few studies have investigated horses' stress responses during EAIs, and further studies are recommended, with the final aim to derive a reliable multidimensional method for assessing a horse's reaction during therapeutic programs, ultimately helping professionals to better develop interventions by taking into consideration the animal's perspective.