The effect of airflow on thermographically determined temperature of the distal forelimb of the horse.
Authors: Westermann S, Stanek C, Schramel J P, Ion A, Buchner H H F
Journal: Equine veterinary journal
Summary
# Editorial summary Even modest airflow significantly affects thermographic readings of equine forelimbs, with temperature drops occurring within 1–3 minutes of wind exposure and varying proportionally to wind velocity. Westermann and colleagues tested this using six horses exposed to three controlled wind speeds (0.5–1.0, 1.3–2.6, and 3.0–4.0 m/s) whilst obtaining sequential thermal images of one forelimb, finding decreases of approximately 0.6°C, 1.5°C and 2.1°C respectively at each wind velocity, and notably larger rewarming responses (1.2–2.1°C) once airflow ceased. Temperature recovery to baseline took around 3 minutes after wind cessation, and the magnitude of thermal change correlated directly with increasing wind speed, demonstrating that seemingly imperceptible draughts can alter readings sufficiently to create diagnostic error. For practitioners performing thermographic assessment of inflammatory conditions in the distal limb—a common clinical application—conducting examinations in genuinely draught-free conditions is therefore non-negotiable; ambient air movement introduces confounding variables that could easily mask or mimic pathological temperature changes, compromising diagnostic accuracy and potentially leading to inappropriate treatment decisions. Future investigation of thermography's reliability across different body regions, ambient temperatures and in horses with active inflammatory lesions would help establish more robust clinical protocols.
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Practical Takeaways
- •Always perform equine thermography in a completely draught-free room—even slight air movement (0.5 m/s) produces significant temperature artefacts that could mask or mimic pathology
- •Allow 3+ minutes stabilization time after any air exposure before capturing images, as forelimb temperatures continue changing during this period
- •Recognize that thermographic findings obtained in non-standardized environments (stables, barns with ventilation) may not be reliable for diagnostic purposes, particularly for subtle inflammatory lesions of the distal limb
Key Findings
- •Wind velocities of 0.5–1.0 m/s caused a 0.6°C decrease in thermographically determined forelimb temperature within 1–3 minutes; higher velocities (1.3–2.6 m/s and 3.0–4.0 m/s) caused 1.5°C and 2.1°C decreases respectively
- •Temperature recovered by 1.2–2.1°C within 3 minutes after wind cessation, with magnitude proportional to prior wind velocity
- •Temperature differences between baseline and wind-on conditions, and between wind-on and wind-off conditions, increased significantly with increasing wind velocity
- •Even barely noticeable airflow affects thermographic measurements of equine forelimbs, necessitating standardized draught-free conditions to prevent false-positive or false-negative diagnoses