Stress responses of horses transported long-distance by road to and from a jumping competition in a tropical climate.
Abstract: Long-distance road transport is known to be stressful for horses, with most research conducted in temperate climates. This study investigated horses' stress responses during long-distance transport before and after a jumping competition in a tropical environment. Ten healthy horses (aged 7.9 ± 1.9 years) were studied. Blood cortisol concentrations, haematology, and heart rate variability (HRV) were monitored during outbound (OTJ) and inbound journeys (INJ). Cortisol concentrations increased five minutes after unloading and remained elevated for up to 180 minutes in the OTJ (P < 0.05-0.001); during the INJ, levels returned to baseline and remained stable after 60 minutes (P < 0.01-0.001). White blood cell and neutrophil counts were higher in the OTJ than the INJ in the 60 to 180 minutes after unloading (P < 0.05). Beat-to-beat (RR) intervals decreased during 120 minutes of transport (P < 0.05-0.0001) and 60 minutes after unloading (P < 0.05) in OTJ and INJ. Parasympathetic nervous system (PNS) index decreased over 30 minutes during travel (P < 0.01) and 30 minutes after unloading (P < 0.05) in OTJ, while slightly decreasing at 60-90 minutes into the INJ. Heart rate and sympathetic nervous system (SNS) index increased at 30-60 minutes during travel (P < 0.05-0.0001) and 30 minutes after unloading (P < 0.001) in the OTJ, while they increased at 60-90 minutes during travel in the INJ. The standard deviation of the averages of RR intervals in 5-min segments (SDANN) and mean of the standard deviations of RR intervals in 5-min segments (SDNNI) showed greater values during the OTJ than the INJ 330-360 minutes after unloading (P < 0.01-0.001). Stress index increased at 30-120 minutes of travel in both the OTJ and INJ (P < 0.05-0.001). High-frequency (HF) band power increased, with a concurrent decrease in the low-frequency (LF) band and LF/HF ratio at 90-440 minutes of travels (P < 0.05-0.0001 for all variables). Standard deviation 2 (SD2)/standard deviation 1 (SD1) ratio was reduced at 120-600 minutes of travels (P < 0.05-0.0001). Correlations between environmental parameters and HRV variables were mainly observed during the INJ. In summary, horses primarily experienced stress during the initial hours of travel and immediately after unloading. Stress responses differed between journeys and were partly influenced by environments and housing conditions. This study highlights welfare considerations concerning horse transport for equestrian events in tropical climates.
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Publication Date: 2025-06-24 PubMed ID: 40554687DOI: 10.1093/jas/skaf214Google Scholar: Lookup
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Summary
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This study investigates how long-distance transport, before and after a competitive event, affects the stress levels of horses in tropical climates. Results show horses primarily experience stress during the initial hours of travel and immediately after unloading, with varying stress responses between outward (before the competition) and inbound (after the competition) journeys, influenced partly by environmental and housing conditions.
Study Design and Purpose
- The purpose of this study was to understand how long-distance road transport in tropical climates affects the stress levels of horses, with most previous research focusing mainly on temperate climates.
- The research was conducted using ten healthy horses over a period of two journeys – outbound journey (OTJ) to the jumping competition and the inbound journey (INJ) after the competition.
- The stress responses were monitored by analyzing blood cortisol concentrations, haematology, and heart rate variability (HRV).
Findings
- Rising cortisol concentrations, higher white blood cell and neutrophil counts, and changes in heart rate variability were observed, indicating stress during the initial hours of travel and immediately after unloading.
- The researchers noticed differing patterns of stress responses between the OTJ and INJ, suggesting varying stress levels depending on the journey direction and possibly whether the horse had already competed.
- There was also a correlation observed between environmental parameters and HRV variables mainly during the INJ, implying environment and housing conditions’ influence on stress levels.
Implications and Significance
- This study is significant as it provides valuable insights into welfare considerations concerning the transport of horses in tropical climates for equestian events, a field where much of the existing body of research has focused on temperate climates.
- The differences in stress responses between journeys suggests the need for strategies to manage and mitigate stress responses of horses depending on the journey direction (outbound or inbound) and possibly the timing in relation to the competition.
- The correlation between environmental parameters and HRV variables points towards the potential benefits of optimizing environment and housing conditions to improve equine wellbeing during transportation.
Cite This Article
APA
Sanigavatee K, Wonghanchao T, Poochipakorn C, Pongnarudech P, Suchairat T, Jitsopin S, Wanichayanon B, Sripiboon S, Chanda M.
(2025).
Stress responses of horses transported long-distance by road to and from a jumping competition in a tropical climate.
J Anim Sci, skaf214.
https://doi.org/10.1093/jas/skaf214 Publication
Researcher Affiliations
- Department of Large Animal and Wildlife Clinical Science, Faculty of Veterinary Medicine, Kasetsart University, Kamphaeng Saen Campus, Nakhon Pathom 73140, Thailand.
- Thailand Equestrian Federation, Sports Authority of Thailand , Bangkok 10330, Thailand.
- Department of Large Animal and Wildlife Clinical Science, Faculty of Veterinary Medicine, Kasetsart University, Kamphaeng Saen Campus, Nakhon Pathom 73140, Thailand.
- Thailand Equestrian Federation, Sports Authority of Thailand , Bangkok 10330, Thailand.
- Department of Large Animal and Wildlife Clinical Science, Faculty of Veterinary Medicine, Kasetsart University, Kamphaeng Saen Campus, Nakhon Pathom 73140, Thailand.
- Thailand Equestrian Federation, Sports Authority of Thailand , Bangkok 10330, Thailand.
- Veterinary Science Program, Faculty of Veterinary Medicine, Kasetsart University, Kamphaeng Saen Campus, Nakorn Pathom 73140, Thailand.
- Veterinary Science Program, Faculty of Veterinary Medicine, Kasetsart University, Kamphaeng Saen Campus, Nakorn Pathom 73140, Thailand.
- Veterinary Science Program, Faculty of Veterinary Medicine, Kasetsart University, Kamphaeng Saen Campus, Nakorn Pathom 73140, Thailand.
- Veterinary Science Program, Faculty of Veterinary Medicine, Kasetsart University, Kamphaeng Saen Campus, Nakorn Pathom 73140, Thailand.
- Department of Large Animal and Wildlife Clinical Science, Faculty of Veterinary Medicine, Kasetsart University, Kamphaeng Saen Campus, Nakhon Pathom 73140, Thailand.
- Department of Large Animal and Wildlife Clinical Science, Faculty of Veterinary Medicine, Kasetsart University, Kamphaeng Saen Campus, Nakhon Pathom 73140, Thailand.
- Thailand Equestrian Federation, Sports Authority of Thailand , Bangkok 10330, Thailand.
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