|dc.description.abstract||Veterinary care can be essential for maintaining the physical health of horses
and yet the impact of veterinary care on a horse’s emotional state and how
that influences their behavioural responses has not been investigated
previously. The term horses is used to describe both horses and ponies.
Adverse behavioural responses are unwanted, not only for equine welfare
but because veterinarians are frequently injured by the horses they are
working with, each sustaining on average around 7-8 significant injuries over
the courses of their careers. This study evaluated which aspects of veterinary
care horses find stressful, their common behavioural responses in this
context and potential ways of improving how they perceive veterinary care.
In the context of a veterinary examination, horses are limited in which
behavioural responses they can express as they will be restrained to a
greater or lesser degree. To determine the range of behavioural responses
that may occur and their usefulness in assessing emotional state in the
veterinary clinic, a two round Delphi process was undertaken. In the first-round participants from the field of Equitation Science (n=16), Equine
Veterinarians (n=10) and Animal Behaviour and Welfare Scientists (n=7)
evaluated 11 videos of horse’s behavioural responses to veterinary care.
They assigned a score to the degree of stress they perceived each horse to
be experiencing and described any behavioural indicators of stress as free
text. There was poor agreement on the perceived degree of stress the horses
were experiencing and different behavioural indicators were reported by
different individuals. The behavioural indicators (41) identified in round one
were then re-presented to the participants in a second round where 34/41
indicators were considered useful measures of the horse’s stress response in
A feasibility study was then undertaken to determine the best measures of
arousal and valence in the context of a veterinary clinic. Horses presenting
for veterinary care at an equine hospital (n=30) were filmed during various
veterinary interactions (Events) with the horses and the footage was
evaluated using a detailed inventory of behavioural responses. Principle
component analyses were performed, results of which suggested that the
most common behavioural responses to veterinary care were characterised
by freeze or flight.
Evaluation of the feasibility of different measures of arousal (salivary cortisol,
surface eye temperature and heart rate variability) were undertaken on the
same cohort of horses.
Salivary cortisol concentrations highlighted that horses were in a state of
elevated arousal, likely as a consequence of transportation, even before
veterinary care commenced. Elevated cortisol concentrations were
maintained, most likely due to exposure to veterinary Events, but the lag
between an individual Event and concentration peaks / return to baseline
meant this was not feasible measure in this context.
Surface eye temperature provided data that varied in real time and showed
variation between horses and between individual Events. The main limitation
of using this measure was the practical challenges trying to capture usable,
in focus, and therefore accurate, thermal images of the eye as many horses
did not remain still during Events.
Heart rate variability parameters (HRV) provided data that varied in real time
and showed variation between horses and between individual Events.
Moreover, it could be collected remotely and regardless of any behavioural
response. In the feasibility study HRV data were collected using a Polar heart
rate monitor. However, validation against an ECG showed the Polar to be
inaccurate, even following artefact correction. Even when an ECG was used
subsequently, manual R peak detection and documentation of arrhythmias
was essential to ensure accurate data for HRV analyses were generated.
The methodology developed in the feasibility study was used to evaluate the
responses of 60 horses undergoing veterinary care in the same equine
hospital. The proportion of time a horse was ‘stressed’ was calculated based
on the sum total of time in any negative affective state over total time. This
study found marked variation regarding which veterinary Events horses
appeared to find stressful, both within and between individuals. For example,
13/15 veterinary Events resulted in a range of time an individual horse was
scored as ‘stressed’. Negative behavioural responses were characterised by
freeze or flight but also fidgeting behaviours, which are well described in
other species but poorly documented in horses. Aggressive ‘fight’ responses
occurred very infrequently.
Further research is required to determine whether training of equine
veterinarians to recognise subtle behavioural indicators, across the range of
responses (freeze, flight, fidget or fight), can be used to improve equine
welfare and reduce the likelihood of occupational injuries.
With regard to evaluation of individual Events:
• One of the most arousing stimuli, based on behavioural response and
elevated heart rate, in the veterinary environment was the sound or sight
of another horse walking past and so minimising this stimulus where
possible is recommended.
• Horses are frequently walked onto a weigh bridge upon entering the
equine hospital and this commonly evoked a behavioural response
characterised by freeze or flight and elevated heart rate. It is less than
ideal that their first experience in a novel environment and first interaction
with staff may be a negative one. Weighing a horse after other veterinary
Events have been completed or development of a low stress technique
would likely be of benefit.
• The use of feed during diagnostic local anaesthesia appeared to minimise
the proportion of time an equid was scored as ‘Stressed’ compared to
when it was not used and so is recommended.
• Horses were scored as more ‘Stressed’ when an I.V. injection was
administered by a student or nurse in comparison to a veterinarian.
Investigation of training to try to mitigate this response should be
The final study in this thesis evaluated the way in which learning theory could
be applied in veterinary practice. Classical counter conditioning was used
prior to diagnostic local analgesia (nerve blocks) and the impact on the
horse’s stress response was investigated. Twenty-seven cases presenting
for lameness evaluation were recruited and randomly assigned to a control or
treatment group. In the treatment group the provision of feed (unconditioned
stimulus) was paired with someone approaching (conditioned stimulus) the
limb. In the control group 14 horses received 24 nerve blocks, in the
treatment group 13 horses received 35 nerve blocks. Restraint during the
nerve block was at the discretion of the veterinarian performing the
procedure. Video footage of horses during the nerve block was evaluated
using a fixed list method Qualitative Behaviour Assessment by 5 observers
blinded to treatment group. They scored the treatment group as being in a
more positive affective state (at ease, relaxed and confident) than the control
group (nervous, tense and fearful). However, the difference between groups
was only statistically significant once other significant contributing factors
such as the type of block were included in the multivariable model. This
highlights that many different factors are contributing to how a horse
perceives veterinary Events such as nerve blocks but that classical counter
conditioning can be used to help horses perceive them more positively.
In summary, a horse’s perception of veterinary care will vary markedly
between individual animals but also within an individual. Constant evaluation
of the horse’s emotional state, based on an understanding of subtle
indicators of negative affect, will allow the veterinary team to modify their
approach and optimise care of the individual. In addition, it is possible to
promote a positive affective state even during aversive procedures such as
nerve blocks. This can be achieved in a real-life scenario using classical
|dc.publisher||The University of Edinburgh||en
|dc.relation.hasversion||DOHERTY, O., MCGREEVY, P. D. & PEARSON, G. 2017. The importance of learning theory and equitation science to the veterinarian. Applied Animal Behaviour Science, 190, 111-122||en
|dc.relation.hasversion||HALL, C., KAY, R., RANDLE, H., PRESHAW, L. PEARSON, G. AND WARAN, N. Indicators on the outside: Behaviour and equine Quality of Life 15th international equitation science conference, 2019 Guelf, Canada||en
|dc.relation.hasversion||PEARSON, G. 2017. Equine Learning Theory and the Horse-Veterinarian Interaction. MScR, The University of Edinburgh.||en
|dc.relation.hasversion||PEARSON, G. 2019. Managing difficult behaviour in horses. In Practice, 41, 329.||en
|dc.relation.hasversion||PEARSON, G., CONNOR, M., KEEN, J., REARDON, R. & WARAN, N. 2020a. Incorporation of Equine Learning Theory into the Undergraduate Curriculum. Journal of veterinary medical education, e20190078||en
|dc.relation.hasversion||PEARSON, G., REARDON, R., KEEN, J. & WARAN, N. 2020b. Difficult horses – prevalence, approaches to management of and understanding of how they develop by equine veterinarians. Equine veterinary education, 1-9.||en
|dc.subject||low stress handling||en
|dc.subject||classical counter conditioning||en
|dc.title||Stress in equids undergoing veterinary care and the development of interventions that positively influence the horses' experience||en
|dc.type||Thesis or Dissertation||en
|dc.type.qualificationname||PhD Doctor of Philosophy||en