Effect of head and neck position on upper airway function in standardbred racehorses
Date
2014
Authors
Johnson, K.
Noschka, E.
Allen, K.
Tilbrook, A.
Ryan, T.
Franklin, S.
Editors
Advisors
Journal Title
Journal ISSN
Volume Title
Type:
Conference item
Citation
Equine Veterinary Journal, 2014, vol.46, iss.S46, pp.22-22
Statement of Responsibility
Johnson K, Noschka E, Allen K, Tilbrook A, Ryan T, Franklin S
Conference Name
9th International Conference on Equine Exercise Physiology (15 Jun 2014 - 20 Jun 2014 : Chester, UK)
Abstract
<jats:sec><jats:title>Introduction</jats:title><jats:p>Poll flexion may play an important role in the development of dynamic upper respiratory tract (<jats:styled-content style="fixed-case">URT</jats:styled-content>) collapse. However, limited investigations have been performed in Standardbred racehorses.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>Eight Standardbreds were examined during training, once flexed and once in extension, using a randomised crossover design. Head position was maintained using modified check‐reins and head‐neck angle was recorded. On each occasion horses performed 2 rounds of exercise of 2400 m at ∼35 km/h. Speed and heart rate (<jats:styled-content style="fixed-case">HR</jats:styled-content>) were measured and blood obtained before and after exercise. <jats:styled-content style="fixed-case">URT</jats:styled-content> endoscopy was performed during the second round. Videos were blinded and <jats:styled-content style="fixed-case">URT</jats:styled-content> function assessed. <jats:styled-content style="fixed-case">HR</jats:styled-content>, plasma lactate (Lac) and speed were compared for different head positions using paired t‐tests. Cortisol was analysed using repeated‐measures <jats:styled-content style="fixed-case">ANOVA</jats:styled-content> and <jats:styled-content style="fixed-case">URT</jats:styled-content> function using Fisher's exact tests and paired t‐tests (P<0.05).</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>Data were excluded for one horse where head‐neck angle could not be measured. Flexed and extended head‐neck angles differed significantly (mean: 85.0° vs 97.8°; P = 0.001). All horses showed some form of <jats:styled-content style="fixed-case">URT</jats:styled-content> collapse during exercise, although this was only deemed clinically significant in 4 horses with a history of abnormal noise. These horses showed additional abnormalities during flexion. However, mean severity scores did not reach statistical significance (P = 0.08). No significant difference was found for speed, <jats:styled-content style="fixed-case">HR</jats:styled-content> or Lac. A significant increase in cortisol was found with exercise (P<0.001). The interaction between time and head position approached significance (P = 0.09) with higher concentrations of cortisol generally occurring in extension rather than flexion.</jats:p></jats:sec><jats:sec><jats:title>Conclusions</jats:title><jats:p><jats:styled-content style="fixed-case">URT</jats:styled-content> abnormalities may be exacerbated with poll flexion. The use of equipment to modify head position may induce a stress response.</jats:p></jats:sec><jats:sec><jats:title>Ethical Animal Research</jats:title><jats:p>This study was approved by the University of Adelaide Animal Ethics Committee and owner informed consent obtained. <jats:bold>Sources of funding:</jats:bold> University of Adelaide honours projects. <jats:bold>Competing interests:</jats:bold> none.</jats:p></jats:sec>
School/Discipline
Dissertation Note
Provenance
Description
Abstract only
Access Status
Rights
© 2014 The Author(s), © 2014 EVJ Ltd