title: The effect of airflow on thermographically determined temperature of the distal forelimb of the horse.
abstract: BACKGROUND
  Current literature suggests that thermographic imaging of horses should be performed in a draught-free room. However, studies on the effect of airflow on determined temperature have not been published.
  
  
  OBJECTIVE
  To investigate effects of airflow on thermographically determined temperature of horses' forelimbs; to assess the relationship of wind velocity, rectal temperature, ambient temperature and humidity.
  
  
  METHODS
  Thermographic images were obtained for the forelimbs of 6 horses in a draught-free room. Three replicates (R) with defined wind velocities (R1, 0.5-1.0 m/s; R2, 1.3-2.6 m/s; and R3, 3.0-4.0 m/s) were conducted. Each replicate consisted of a baseline image, a 15 min phase with the wind on and a 15 min phase with the wind off. We exposed only the right leg to airflow and determined the temperature by thermography with the wind on and wind off. Temperature differences between baseline and wind on, between wind on and wind off and between different wind velocities were analysed by a general linear model, Student's paired t test and ANOVA.
  
  
  RESULTS
  After the onset of wind, the temperature on the right forelimb decreased within 1-3 min (by approximately 0.6°C at R1, 1.5°C at R2 and 2.1°C at R3). With the wind off, the temperature increased within 3 min (by approximately 1.2°C at R1, 1.7°C at R2 and 2.1°C at R3). With increasing wind velocity, the temperature differences between baseline and wind on and between wind on and wind off increased significantly.
  
  
  CONCLUSIONS
  Barely noticeable wind velocities caused a decrease in thermographically determined temperatures of the forelimbs of the horse. Further research is required to assess the influence of airflow on other parts of the body and at different ambient temperatures, as well as the effect on horses with inflammatory lesions, especially of the distal limbs.
  
  
  CONCLUSIONS
  It is essential for practitioners to perform thermography on horses in a draught-free environment in order to avoid false-positive or -negative diagnoses.
authors.affiliation: Large Animal Surgery and Orthopaedics, University of Veterinary Medicine Vienna (Vetmeduni Vienna), Vienna, Austria. simone.westermann@vetmeduni.ac.at
authors.forename: S
authors.initials: S
authors.lastname: Westermann
authors.forename: C
authors.initials: C
authors.lastname: Stanek
authors.forename: J P
authors.initials: JP
authors.lastname: Schramel
authors.forename: A
authors.initials: A
authors.lastname: Ion
authors.forename: H H F
authors.initials: HH
authors.lastname: Buchner
mesh_terms: D000392:Air Movements; D000818:Animals; D001831:Body Temperature / Q000502:physiology*; D005260:Female; D005552:Forelimb / Q000502:physiology*; D006736:Horses / Q000502:physiology*; D008297:Male; D013817:Thermography / Q000662:veterinary*
keywords: airflow; forelimb; horse; thermography; wind velocity