Ground-based adaptive horsemanship lessons for veterans with post-traumatic stress disorder: a randomized controlled pilot study.

Introduction: Equine-assisted services (EAS) has received attention as a potential treatment strategy for post-traumatic stress disorder (PTSD), as existing literature indicates that symptoms may decrease following EAS. Relatively little is known about the mechanisms at play during lessons and if physiological measures are impacted. The objectives of this pilot study were to 1) explore the effects of adaptive horsemanship (AH) lessons on symptoms of PTSD, hormone concentrations, and social motor synchrony; 2) determine if physiological changes occur as veterans interact with horses; and 3) explore if the interaction between veteran and horse changes over the 8-week session. Methods: Veterans with PTSD were randomly assigned to control (CON, n = 3) or AH (n = 6) groups for an 8-week period (clinical trial; NCT04850573; clinicaltrials.gov). Veterans completed the PTSD Checklist (PCL-5) and Brief Symptom Inventory (BSI) at pre-, post-, and 2- and 6-month follow-up time points. They also completed a social motor synchrony test (pendulum swinging) and blood draw at pre- and post-time points. In weeks 1, 4, and 8, blood samples were drawn at 0 min, 3 min, 5 min, 25 min, and 30 min during the 30-min AH lessons. Veterans completed the Human-Animal Interaction Scale (HAIS) after each lesson. Blood samples were assayed for plasma cortisol, epinephrine, norepinephrine, and oxytocin. Data were analyzed with repeated measure ANOVAs. Changes in PTSD symptoms from pre- to post-time point were analyzed with paired t-tests. Results: Changes in PCL-5 scores tended to differ (p = 0.0989), and global BSI scores differed (p = 0.0266) between AH (-11.5 ± 5.5, mean ± SE; -0.5 ± 0.2) and CON (5.3 ± 5.4; 0.4 ± 0.2) groups. Social motor synchrony and hormone concentrations did not differ between groups or time points (p > 0.05). Cortisol, norepinephrine, and oxytocin concentrations did not differ across sessions (p > 0.05). Epinephrine concentrations tended (p = 0.0744) to decrease from week 1 to 4 of sessions. HAIS scores increased (p ≥ 0.0437) in week 3 and remained elevated as compared to week 1. Discussion: Participant recruitment was the greatest challenge. These preliminary results agree with the literature suggesting that EAS can reduce symptoms of PTSD.

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.

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.

The Effects of an External Equine Nasal Strip on Thermoregulation During Exercise.

The purpose of this study was to examine the effects of an external nasal strip on thermoregulation during submaximal exercise in Standardbred horses. While several studies have been conducted to determine the effects of the external nasal strip on airway resistance, exercise induced pulmonary hemorrhage, gas exchange, and time to fatigue in maximally exercising horses, the effects of the nasal strip on equine thermoregulation have not yet been examined. It was hypothesized that the application of an external nasal strip would alter central venous temperature (Tcore), skin temperature (Tskin), and exercise time to reach a central venous temperature of 40 °C. Eight mature Standardbred horses each performed two submaximal exercise trials, one with a nasal strip (NS), and one without (control), on a high-speed equine treadmill with exercise concluding upon Tcore reaching 40 °C. There were no significant differences in Tcore or Tskin between the NS and control groups during pre-exercise, exercise or recovery (P > .05), nor were there differences (P > .05) in exercise time to reach a Tcore of 40 °C (NS: 11.8 ± 1.5 minutes; Control: 11.5 ± 1.1 min). We conclude that the application of an external nasal strip does not affect the equine thermoregulatory response during submaximal exercise.

Effect of Clenbuterol on Muscle Activity During Exercise in Standardbred Horses.

Clenbuterol (ß2 agonist) is a commonly administered bronchodilator in race and performance horses. While long-term administration can alter exercise performance and muscle properties, little is known about its effects on these parameters following short-term administration. A single dose of clenbuterol (0.80 µg/kg) was expected to alter muscle activity of the extensor carpi radialis, semitendinosus, and longissimus dorsi during submaximal exercise. Eight mature Standardbred horses exercised for 2 minutes at 5 m/s on a high-speed treadmill following clenbuterol dosing (clenbuterol) or no dosing (control) in a crossover experimental design. Surface electromyography (sEMG) data were collected continuously from the muscles of interest and processed to determine average rectified value (ARV) and median frequency (MF) of the signal during peak muscle activation (100 ms period) during 15 strides. ARV data were log transformed. Data were analyzed with a mixed model ANOVA with fixed effects of period and treatment and a random effect of horse. No differences (P > .05) in amplitude (ARV) or frequency (MF) of the EMG signal were detected following clenbuterol administration. Thus, a one-time dose of clenbuterol had no statistically detectable effect on muscle activity during submaximal exercise. Further studies should be undertaken to confirm these results and examine the effects of long-term administration on muscle activity during exercise.

Muscular tension as an indicator of acute stress in horses.

Horses' muscular tension during acute stress remains unexplored. Our aim was to assess muscular, behavioral, cortisol, and hematocrit responses to social isolation (ISO), novel object exposure (NOV), and sham clipping (CLIP). Altered stress responses were expected. Eight mature Standardbred horses (four mares and four geldings) were exposed to acute stressors and a control period (CON) in a balanced, replicated 4×4 Latin Square experimental design with 3 min treatment periods and 10 min washout periods. Surface electromyography collected from the masseter, brachiocephalas, cervical trapezius, and longissimus dorsi was processed to derive average rectified value (ARV) and median frequency (MF) during the initial, middle, and final 30 s of treatments. ARV and MF data were log transformed then analyzed using a mixed model, repeated measures ANOVA along with plasma cortisol and hematocrit. Behavior data were analyzed using a negative binomial distribution mixed model ANOVA. CLIP resulted in greater (p < 0.05) log ARV in the masseter (1.5 + 1.5%, mean + SD) and brachiocepahlas (2.2 + 2.0%) than CON (-1.2 + 1.4%, 0.1 + 1.5%). ISO resulted in greater (p < 0.05) log ARV in the masseter (0.2 + 1.3%) and cervical trapezius (0.6 + 1.3%) than CON (-1.2 + 1.4%, -1.0 + 1.7%). ISO increased (p < 0.05) the total number of stress-related behaviors and hematocrit. No changes in cortisol were observed. We suggest that muscular tension can be used as an indicator of acute stress in horses. Incorporating muscle activity into an array of measurements may provide a more nuanced understanding of stress responses.

A Survey of Horse Selection, Longevity, and Retirement in Equine-Assisted Services in the United States.

Little published information exists on the horses in equine-assisted services (EAS), particularly their selection, longevity, and retirement. The purpose of this study was to characterize horses and procedures used in EAS. A pilot survey was developed using focus group discussions and distributed to Professional Association of Therapeutic Horsemanship, International (PATH Intl) centers in Florida (n = 45, Part I) before further modification and distribution to members of PATH Intl., American Hippotherapy Association (AHA), eagala, and Certified Horsemanship Association (CHA) (n = 26,000, Part II). Response rates were 36% (Part I) and 0.7% (Part II). Centers report a median of 10 (Part I) or 9 (Part II) horses and ponies. Selection procedures included initial screening (Part I = 100%, Part II = 96%), pre-purchase or pre-donation exam (I = 64%, II = 60%), acclimation period (I = 100%, II = 84%), trial period (I = 91%, II = 90%), and other (II = 11%). Horses remained active in programs for less than a year to over 20 years with the greatest number working 7-10 (Part I) or 1-6 (Part II) yr. In Part I of the study, behavior (44%) was the leading cause of retirement followed by unsoundness (33%). In Part II, unsoundness was the highest ranked response followed by behavior. Behavior, soundness, and health emerged as key factors in horse selection and retirement. Future work should focus on investigating these issues at an individual horse level.

Horse Racing and Veterinary Practices in New Jersey.

The New Jersey horse racing industry has declined over the last 5 years as indicated by decreases in the number of racing days, stallions standing, mares bred, and foals registered. These changes were hypothesized to have potential negative consequences for veterinary practices. The objective of the survey was to investigate changes in veterinary practice revenue and staff over a five-year period. Members of the New Jersey Association of Equine Practitioners completed a survey detailing their involvement in the horse racing industry and breeding of racehorses. A response rate of 49% was achieved with 45% of respondents indicating they were involved in the horse racing industry as a veterinarian. Respondents indicated they decreased (44%), did not change (17%), or increased (39%) their number of staff because of changes in the horse racing industry over the past 5 years. In a similar manner, veterinarians reported decreases (48%), no change (22%), or increases (30%) in revenue. Practice revenue from the breeding of racehorses and its associated components either decreased (91%) or did not change (9%) over the past 5 years because of changes in the horse racing industry. Results indicate declines in the horse racing industry had minimal impact on veterinary practices involved in this sector of the industry. Veterinarians and practices involved in racehorse breeding and its associated components, in contrast, were negatively impacted by changes in the horse racing industry.

Paul D. Sturkie: Avian cardiac physiologist.

Sturkie's Avian Physiology is a highly regarded textbook for the study of comparative poultry physiology. Less well known, however, is the contribution of Paul D. Sturkie (1909-2002) as a pioneer in the experimental physiology of avian species. His seminal research on the cardiovascular and hemodynamic controls of chickens and egg-laying hens had a notable impact on the poultry industry and breeding practices of farmers. The purpose of this article is to highlight the contributions and practical insights of Paul D. Sturkie to the field of poultry science.

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.

Changes in adipopnectin, leptin, and fat mass after clenbuterol treatment in horses.

INTRODUCTION: Adipose tissue plays complex role(s) in metabolic and endocrine control. To date, little work has been done in the horse regarding adipocytokines. PURPOSE: This study was conducted to determine whether therapeutic levels of chronic beta-agonist administration, exercise, or both could alter their concentrations. METHODS: A total of 23 standard-bred mares were divided into four experimental groups: clenbuterol (2.4 microg.kg(-1) bw twice daily for 8 wk) plus exercise (8 wk, 20 min.d(-1) at 50% VO2max; CLENEX; N = 6), clenbuterol only (CLEN; N = 6), exercise only (EX; N = 5), and control (CON; N = 6). Rump fat thickness was measured using B-mode ultrasound and percent body fat (%fat) was calculated. Plasma adiponectin and leptin concentrations were measured using radioimmunoassay (RIA). In the absence of purified equine adiponectin or leptin, results were expressed as human equivalents of immunoreactive adipocytokines. RESULTS: The change in plasma immunoreactive (ir)-adiponectin HE concentration was negatively correlated (r = -0.520; P = 0.01) to the change in fat mass and positively correlated (r = 0.446; P = 0.03) to the change in fat-free mass. The change in plasma ir-leptin HE concentration was positively correlated (r = 0.550; P = 0.02) to the change in fat mass and negatively correlated (r = -0.473; P < 0.05) to the change in fat-free mass. CONCLUSION: These data demonstrate that a chronic clenbuterol administration alters the concentrations of the adipocytokines adiponectin and leptin in horses. These changes may play a role in previously reported repartitioning effects of clenbuterol.

Adiponectin and leptin are related to fat mass in horses.

Plasma concentrations of adiponectin and leptin were measured in 23 mature Standardbred mares (age: 10+/-3 years) and 12 weanling fillies (10 Quarter Horse/Belgian crossbreds and two Quarter Horses; aged: 4+/-3 months) to test the hypothesis that adipocytokines are proportional to adiposity in horses. Rump fat thickness was measured using B-mode ultrasound and percent body fat (% fat) calculated using a published formula for the estimation of fatness in horses. Plasma adiponectin and leptin were determined using radioimmunoassay. In the absence of purified equine adiponectin or leptin, results were expressed as human equivalents (HE) of immunoreactive (ir) adipocytokines. Plasma ir-leptin HE concentration was positively correlated (r=0.543; P<0.001) with percent body fat and (r=0.556; P<0.001) to fat mass in all horses. The plasma ir-leptin HE concentration was lower (P=0.03) in weanlings (1.90+/-0.34 ng/mL HE) than in mature mares (3.47+/-0.50 ng/mL HE). The ratio of ir-adiponectin HE to ir-leptin HE was negatively correlated (r=-0.621; P<0.001) to percent fat and (r=-631; P<0.001) to fat mass in all horses. The ratio of ir-adiponectin HE to ir-leptin HE was higher (P<0.001) in weanlings (3.04+/-0.51) than mature mares (1.03+/-0.13). These data suggest that leptin is proportional while adiponectin is inversely proportional to adiposity in horses.