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Home / Equine Research Bank / Vet Med Sci / Assessment of Blood Profiles and Pain in Sport Horses Underg...
Veterinary medicine and science2026; 12(2); e70678; doi: 10.1002/vms3.70678

Assessment of Blood Profiles and Pain in Sport Horses Undergoing Intrarectal Ozone Therapy.

Abstract: Medical ozone is used in various treatments due to its oxidising properties. Objective: We aimed in this study to evaluate the impact of intrarectal ozone therapy on haematological and biochemical parameters, as well as the pain induced by the procedure in sport horses. Methods: In vivo experiment with 12 Quarter Horses (3 males and 9 females) used as their own controls to assess the effects of ozone therapy. Methods: Blood samples were collected before treatment (Control), 24 h after ozone therapy (24 h post-treatment), and 7 days after the last day of ozone therapy (7 days post-treatment). These samples were analysed for haematological and biochemical parameters. Pain assessment, clinical evaluation, and the measurement of heart rate (HR) and respiratory rate (RR) were conducted before and during ozone therapy. Results: Ozone therapy significantly affected haemoglobin (F = 5.55; p = 0.012), mean corpuscular haemoglobin concentrations (MCHC) (F = 16.01; p < 0.001), and aspartate aminotransferase (AST) activity (F = 20.49; p < 0.001). Specifically, haemoglobin concentration decreased 24 h after ozone therapy, MCHC levels increased 7 days post-ozone therapy, and AST activity decreased 7 days post-ozone therapy. Blood smears taken 24 h post-treatment revealed red blood cells with membrane deformities, which normalised by 7 days post-treatment. None of the animals exhibited clinical symptoms, although pain scores increased, although pain scores increased (before: 4.2 ± 0.4; during: 5.3 ± 0.4; F = 5.20; p = 0.025). The reduction in haemoglobin was likely due to oxidative damage, which stimulated the production of erythrocytes with higher haemoglobin content. Lower AST levels suggested an absence of liver damage. The increase in pain scores suggests that using lower concentrations or doses in future studies might alleviate discomfort in the animals. Conclusions: The study's applicability is limited by the small sample size, particularly the number of males, yet the findings provide valuable insights. Conclusions: Overall, the administration of intrarectal ozone therapy over a 7-day period in horses was associated with favourable haematological modifications, which may suggest an enhancement in systemic tissue oxygenation.
© 2025 The Author(s). Veterinary Medicine and Science published by John Wiley & Sons Ltd.
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Publication Date: 2026-03-07 PubMed ID: 41793261PubMed Central: PMC12966961DOI: 10.1002/vms3.70678Google 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.

Overview

  • This study evaluated how intrarectal ozone therapy affects blood parameters and pain in sport horses.
  • The researchers measured blood changes and pain responses before and after ozone treatment to understand its physiological impact and safety in horses.

Introduction and Objectives

  • Medical ozone is a treatment used for its oxidizing properties, believed to have therapeutic effects.
  • The study aimed to examine how intrarectal ozone therapy influences haematological (blood) and biochemical parameters in sport horses.
  • A secondary goal was to assess the pain induced by the therapy procedure itself in the horses.

Methods

  • Subjects: 12 Quarter Horses (3 males, 9 females) were used, with each horse serving as its own control.
  • Blood Sampling: Blood was collected at three time points:
    • Before treatment (Control)
    • 24 hours after ozone therapy (24 h post-treatment)
    • 7 days after the last ozone therapy session (7 days post-treatment)
  • Parameters analyzed in blood included:
    • Haematological: haemoglobin concentration, mean corpuscular haemoglobin concentration (MCHC), and blood cell morphology.
    • Biochemical: aspartate aminotransferase (AST) activity, an indicator linked to liver function.
  • Pain Assessment: Evaluated before and during ozone therapy sessions using a scoring method.
  • Additional Monitoring: Clinical evaluation along with heart rate (HR) and respiratory rate (RR) were recorded to detect any physiological signs of distress.

Results

  • Haematological Changes:
    • Haemoglobin levels decreased 24 hours after ozone therapy, likely indicating oxidative damage to red blood cells.
    • MCHC increased 7 days post-treatment, suggesting the body produced red blood cells with higher haemoglobin content to compensate.
    • Blood smears showed red blood cells with membrane deformities at 24 hours, which returned to normal by day 7.
  • Biochemical Findings:
    • AST activity decreased 7 days after treatment, suggesting no liver damage occurred due to ozone therapy.
  • Pain and Clinical Observations:
    • Pain scores increased statistically during ozone treatment (from 4.2 to 5.3 on their scale), indicating discomfort associated with the procedure.
    • Despite increased pain scores, no clinical symptoms such as abnormal heart or respiratory rates were observed.

Interpretation of Findings

  • The decrease in haemoglobin immediately after ozone therapy is attributed to oxidative stress damaging existing red blood cells.
  • The subsequent increase in MCHC reflects a physiological response to produce more robust erythrocytes possibly enhancing oxygen transport.
  • Reduced AST levels indicate that the liver was not adversely affected by the therapy, reassuring its safety regarding hepatic function.
  • The increase in pain scores suggests that although the therapy is generally safe, it causes some discomfort, which might be improved by adjusting ozone dosage or concentration in future treatments.

Limitations

  • Small sample size of just 12 horses limits the statistical power and generalizability of findings.
  • Skewed gender distribution with fewer males (3) compared to females (9) might affect how representative the results are across sexes.
  • The study monitored only short- to medium-term responses (up to 7 days post-treatment), so long-term effects remain unknown.

Conclusions

  • Intrarectal ozone therapy over a 7-day period resulted in favorable haematological changes that may improve systemic tissue oxygenation in sport horses.
  • The therapy appeared safe without liver damage but did cause mild to moderate pain, indicating a need to optimize dosing strategies.
  • Future research with larger, more balanced samples and varied dosing regimens could provide more definitive guidance on clinical use.

Cite This Article

APA
de Luna Paiva TD, de Melo Lopes AR, Silva ÁJC, Figueiredo MAF, da Cunha Nogueira SS, Nogueira-Filho SLG. (2026). Assessment of Blood Profiles and Pain in Sport Horses Undergoing Intrarectal Ozone Therapy. Vet Med Sci, 12(2), e70678. https://doi.org/10.1002/vms3.70678

Publication

Veterinary medicine and science
ISSN: 2053-1095
NlmUniqueID: 101678837
Country: England
Language: English
Volume: 12
Issue: 2
Pages: e70678
PII: e70678

Researcher Affiliations

de Luna Paiva, Thamirys Dias
  • Departamento de Ciências Agrárias e Ambientais, Universidade Estadual de Santa Cruz, Ilhéus, Brazil.
de Melo Lopes, Anna Rita
  • Departamento de Ciências Agrárias e Ambientais, Universidade Estadual de Santa Cruz, Ilhéus, Brazil.
Silva, Álvaro José Chávez
  • Departamento de Ciências Agrárias e Ambientais, Universidade Estadual de Santa Cruz, Ilhéus, Brazil.
Figueiredo, Maria Amélia Fernandes
  • Departamento de Ciências Agrárias e Ambientais, Universidade Estadual de Santa Cruz, Ilhéus, Brazil.
da Cunha Nogueira, Selene Siqueira
  • Departamento de Ciências Biológicas, Universidade Estadual de Santa Cruz, Ilhéus, Brazil.
Nogueira-Filho, Sérgio Luiz Gama
  • Departamento de Ciências Agrárias e Ambientais, Universidade Estadual de Santa Cruz, Ilhéus, Brazil.

MeSH Terms

  • Animals
  • Ozone / therapeutic use
  • Ozone / administration & dosage
  • Horses
  • Male
  • Female
  • Pain / veterinary
  • Horse Diseases / blood
  • Horse Diseases / drug therapy
  • Pain Measurement / veterinary

Conflict of Interest Statement

The authors have declared no conflicting interests.

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