Short-term transport stress and supplementation alter immune function in aged horses.
Authors: Miller Ashton B, Harris Patricia A, Barker Virginia D, Adams Amanda A
Journal: PloS one
Summary
# Editorial Summary: Short-term Transport Stress and Supplementation in Aged Horses Even brief transport of 1.5–2 hours triggers significant physiological and immune disruption in aged horses (15–30 years), with cortisol elevation, increased body temperature, and marked shifts in inflammatory cytokine expression occurring within 15 minutes of arrival. When twelve geriatric horses received either an antioxidant supplement (beginning three weeks pre-transport and continuing three weeks post-transport) or served as controls, researchers tracked immune markers via blood sampling at multiple timepoints, measuring gene expression of key cytokines (IL-1β, IL-2, IL-6, IL-10, TNF-α, IFN-γ) and serum amyloid A (SAA1), alongside functional immune cell responses using flow cytometry. The transport event itself decreased pro-inflammatory responses (IL-1β, TNF-α, IFN-γ) whilst paradoxically increasing anti-inflammatory IL-10 and IL-2, suggesting immune dysregulation rather than simple activation; supplemented horses showed significantly reduced IL-1β and SAA1 expression, indicating dampened inflammatory burden. Most critically, immune parameters showed their greatest alterations immediately post-transport (15 minutes) but typically normalised by day one, yet this narrow window of vulnerability warrants attention for practitioners managing geriatric horses, particularly regarding infection risk, feeding practices, and turnout timing around transport events. The immunomodulatory potential of targeted antioxidant supplementation in aged horses merits further investigation as a practical intervention during transport-associated stress.
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Practical Takeaways
- •Aged horses (15+ years) are immunologically vulnerable during and immediately after short transport—consider timing of transport, pre-transport planning, and close health monitoring in the 24 hours post-arrival.
- •Antioxidant supplementation started 3 weeks before transport may help reduce inflammatory markers in aged horses; consider this for animals known to travel poorly or those with compromised immune status.
- •Most immune changes resolve within 24 hours, but the acute window (first 15 minutes post-transport) represents peak disease risk; segregate newly transported older horses and monitor for signs of illness.
Key Findings
- •Short-term transport (1.5-2 hours) increased cortisol, body temperature, and pro-inflammatory cytokines (IL-2, IL-6, IL-10) while decreasing anti-inflammatory markers (IL-1β, TNF-α, IFN-γ) in aged horses.
- •Immune responses were most severely altered at 15 minutes post-transport and typically recovered by Day 1, indicating a critical vulnerability window.
- •Antioxidant supplementation for 3 weeks perioperative decreased IL-1β and serum amyloid A expression, suggesting potential anti-inflammatory benefits in aged horses.
- •Transport and supplementation did not affect body weight, heart rate, or in vitro T-cell cytokine production capacity (IFN-γ and TNF-α after stimulation).