Responses of Horses to Ground-based Lessons for PTSD affected Veterans

Behavioral and Physiological Responses of Horses to Ground-based Adaptive Horsemanship Lessons for Veterans with Post-Traumatic Stress Disorder (PTSD)

J Equine Vet Sci. 2024 Mar 19:105049. doi: 10.1016/j.jevs.2024.105049. Online ahead of print.
Authors
Ellen M Rankins 1 , Kenneth H McKeever 2 , Karyn Malinowski 3
Affiliations

1 Equine Science Center, Department of Animal Sciences, Rutgers, The State University of New Jersey, New Brunswick, New Jersey, USA. Electronic address: ellen.rankins@colostate.edu.
2 Equine Science Center, Department of Animal Sciences, Rutgers, The State University of New Jersey, New Brunswick, New Jersey, USA. Electronic address: mckeever@sebs.rutgers.edu.
3 Equine Science Center, Department of Animal Sciences, Rutgers, The State University of New Jersey, New Brunswick, New Jersey, USA. Electronic address: karynmal@njaes.rutgers.edu.

PMID: 38513814
DOI: 10.1016/j.jevs.2024.105049

Abstract

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. Keywords: behavior; equine-assisted services; hormones; qualitative behavior assessment; stress. Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.