Hold your horses: the effect of play behaviour in horses (Equus caballus) under imposed stress
Date
2024
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of the Witwatersrand, Johannesburg
Abstract
In animals, stress is inevitable, often resulting in behavioural and physiological responses to stressors. Due to the negative connotation of stress and positive connotation of play behaviour, stress and play are concepts not often coupled in research. A few studies have shown a negative association between play and stress whereas others have shown a positive association. Horses (Equus caballus), especially those in equestrian sports, are prone to acute and chronic stress. My study aimed to ascertain whether and how play behaviours can ameliorate acute stress in horses from two different stabling and working conditions (i.e. housed in a stable or on a farm). My study involved investigating the behaviours and decision- making (cognition) of the individual horses in a Y maze for a food reward. All horses were exposed to three treatments in sequence, following a repeated measures design: baseline – without a stressor; stress - exposing the horses to a short-term acoustic stressor; and play - exposing horses to a short term acoustic stressor and then initiating object play with them. Treatments were repeated twice. I recorded the behaviours of the horses and later extracted the following variables: behavioural diversity (i.e. number of behaviours displayed/total potential
behaviours); frequency of behaviours (number of behaviours per 10 seconds); emotional states (positive, negative and neutral), and the time taken (latency) for the horse to make a decision in the maze. I recorded whether they made decisions at two points: 1) the decision point in the maze and 2) for a food reward located at one terminal arm of the maze; the two decisions could be uncoupled. I collected saliva from each horse before and after each treatment for later analysis of cortisol levels. I found that the horses in the stress treatment showed greater diversity and frequency of behaviours linked to a negative emotional state as well as poor
decision-making compared to the play and baseline treatments. Overall, decision-making was better in the play treatment than in the baseline and stress treatments. The horses at the stable, housed under more constrained conditions were more stressed than the horses on the farm. Male horses also appeared to be more stressed compared to the female horses. Salivary cortisol was not a significant predictor of any behaviours and decision-making, nor was it predicted by
treatments, stabling or sex. I found that play is able to ameliorate stress behaviourally and that it improves decision-making, which indicates that play behaviour could be a useful indicator of animal welfare. It is, however, also evident that the behavioural and physiological response to a stressor appears to be decoupled in the horses selected for study.
Description
A research report submitted in partial fulfillment of the requirements for the degree of Master of Science thesis in the school of Animal Plant and Environmental Science, University of the Witwatersrand, 2024
Keywords
Cognition, Decision-making, Horses, Play, Salivary cortisol, Stress, UCTD
Citation
Howard, Jodi Anne. (2024). Hold your horses: the effect of play behaviour in horses (Equus caballus) under imposed stress [Master’s dissertation, University of the Witwatersrand, Johannesburg]. WireDSpace.https://hdl.handle.net/10539/42153