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BMC veterinary research2021; 17(1); 329; doi: 10.1186/s12917-021-02985-9

Salivary cortisol and eye temperature changes during endurance competitions.

Abstract: The purpose of this study was to investigate the usefulness of salivary cortisol (SC) and eye temperature measured by infrared thermography (IRTET) as biomarkers to manage competitions more effectively and monitor horse welfare in endurance competitions. Based on previous studies, it was hypothesised that pre-exercise baseline SC and IRTET would be higher in younger or less experienced horses, and that post-exercise variation from baseline would be higher in the top finishers. Results: Salivary cortisol measured in 61 competing at qualifier 40 km and 80 km rides showed an abrupt variation (93-256% rise) of the baseline SC levels [median ± interquartile range (IQR) = 0.27 ng/dl ± 0.36] obtained at the Pre-Inspection (PI) into Vet Gate (VG)1 independently of the covered distance, but modest or even lower in the subsequent Vet Gates, e.g. VG2 or VG3. The IRTET measured concomitantly in 16 horses showed significant (p < 0.05) higher levels at the PI in less experienced horses participating in the 40 km ride (median ± IQR = 35.7 °C ± 1.4) than their counterparts in the 80 km ride (median ± IQR = 35.0 °C ± 1.5), but not SC. Baseline SC levels at the PI of horses classifying in the Top5 in the 40 km ride category were significantly (p < 0.05) higher median ± IQR = 0.90 ng/ml ±0.61) when compared to horses positioned from 10th position on (median ± IQR = 0.16 ng/ml ±0.40). A lower IRTET in the PI was correlated with better placement (p < 0.05) and those in the Top5 (median ± IQR = 33.9 °C ± 0.0) had a significantly (p < 0.5) higher variation (+ 10.65%) into the last VG. Conclusions: Pre-exercise baseline IRTET levels, but not SC, were higher in less experienced horses in the 40 compared to their counterparts in the 80 km ride competitions. SC and IRTET showed different indications according to the competition. In the40 km ride competition, higher baseline pre-exercise SC levels seemed to be linked to a better classification outcome. In contrast, in the 80 km ride horses, the higher IRTET variation from pre-exercise into final Vet Gate was the parameter associated with a better performance. A more controlled environment and a larger sample are needed to confirm these results and monitor horse welfare in competitions.
© 2021. The Author(s).
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Publication Date: 2021-10-14 PubMed ID: 34649565PubMed Central: PMC8515720DOI: 10.1186/s12917-021-02985-9Google Scholar: Lookup
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  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

This research article examines how saliva cortisol levels and eye temperature readings can be used as biological markers to measure horse welfare during endurance competitions. It concludes that pre-exercise eye temperature levels are higher in inexperienced horses, with higher fluctuation of these markers indicating better performance outcomes.

Study Purpose

  • The study aimed to explore the use of salivary cortisol (SC) and eye temperature readings, measured using infrared thermography (IRT), as biomarkers for better management of endurance competitions as well as monitoring the welfare of the horses involved.
  • The authors hypothesized that younger or less experienced horses would have higher pre-exercise baseline SC and IRT levels, and that variations from these baseline values post-exercise would be greater in top-performing horses.

Findings

  • Salivary cortisol levels of 61 horses competing in 40 km and 80 km endurance rides exhibited a rise of 93-256% from pre-existing baseline levels at the Pre-Inspection (PI) stage to Vet Gate (VG) 1, irrespective of the distance covered by the competitors.
  • These levels showed modest or lower variations at subsequent Vet Gates.
  • The IRT readings of 16 horses simultaneously exhibited significantly higher levels at the PI in less experienced horses participating in the 40 km ride as compared to their more experienced counterparts participating in the 80 km ride.
  • However, there was no difference noticed in the levels of SC.

Conclusions

  • The pre-exercise baseline IRT levels were higher in less experienced horses in the 40 km ride compared to their counterparts in the 80 km endurance competitions. However, cortisol level did not follow the same pattern.
  • For the 40 km ride competition, higher baseline pre-exercise SC levels seemed to indicate a better potential for top placements in the competition.
  • For the 80 km ride, an increase in IRT variation between pre-exercise and the final Vet Gate was found to be associated with better competition performance.
  • The researchers suggested a need for further studies with a more controlled environment and a larger sample size to confirm these findings and improve the monitoring of horse welfare in competitions.

Cite This Article

APA
de Mira MC, Lamy E, Santos R, Williams J, Pinto MV, Martins PS, Rodrigues P, Marlin D. (2021). Salivary cortisol and eye temperature changes during endurance competitions. BMC Vet Res, 17(1), 329. https://doi.org/10.1186/s12917-021-02985-9

Publication

BMC veterinary research
ISSN: 1746-6148
NlmUniqueID: 101249759
Country: England
Language: English
Volume: 17
Issue: 1
Pages: 329

Researcher Affiliations

de Mira, Monica C
  • MED - Mediterranean Institute for Agriculture, Environment and Development, Institute for Advanced Studies and Research, Universidade de Évora, Pólo da Mitra, Ap. 94, 7006-554, Évora, Portugal. monicademira@gmail.com.
Lamy, Elsa
  • MED - Mediterranean Institute for Agriculture, Environment and Development, Institute for Advanced Studies and Research, Universidade de Évora, Pólo da Mitra, Ap. 94, 7006-554, Évora, Portugal.
Santos, Rute
  • MED - Mediterranean Institute for Agriculture, Environment and Development, Institute for Advanced Studies and Research, Universidade de Évora, Pólo da Mitra, Ap. 94, 7006-554, Évora, Portugal.
  • VALORIZA - Research Centre for Endogenous Resource Valorization, Edifício BioBIP, Campus Politécnico, 10, 7300-555, Portalegre, Portugal.
Williams, Jane
  • Hartpury University, Gloucester, GL19 3BE, UK.
Pinto, Mafalda Vaz
  • MED - Mediterranean Institute for Agriculture, Environment and Development, Institute for Advanced Studies and Research, Universidade de Évora, Pólo da Mitra, Ap. 94, 7006-554, Évora, Portugal.
Martins, Pedro S
  • Departamento de Medicina Veterinária, Universidade de Évora, Núcleo da Mitra, Apartado, 94 7006-554, Évora, Portugal.
Rodrigues, Patrícia
  • Departamento de Medicina Veterinária Portugal, Escola Universitária Vasco da Gama, Av. José R. Sousa Fernandes, Campus Universitário - Bloco B, Lordemão, 3020-210, Coimbra, Portugal.
Marlin, David
  • David Marlin Consulting, AnimalWeb Ltd, Cambridge, CB4 0WZ, UK.

MeSH Terms

  • Animals
  • Body Temperature
  • Female
  • Horses / physiology
  • Hydrocortisone / chemistry
  • Hydrocortisone / metabolism
  • Male
  • Ocular Physiological Phenomena
  • Physical Conditioning, Animal / physiology
  • Physical Endurance
  • Saliva / chemistry
  • Sports

Grant Funding

  • [grant UIDB/05064/2020] / Instituto Nacional de Ciência e Tecnologia em Medicina Assistida por Computação Científica (BR)
  • UID/AGR/00115/2019 and research contract CEECIND/04397/2017 / Fundação para a Ciência e a Tecnologia

Conflict of Interest Statement

Elsa Lamy is an editorial board member of BMC Veterinary Research, as associate editor. None of the other authors has any financial or personal relationships that could inappropriately influence or bias the content of the paper.

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Citations

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