075 Development of an equine non-contact thermography device: Relationship of ocular and rectal temperatures to indicators of health status in horses

Abstract

Rectal temperature is commonly used in the horse industry to distinguish between febrile and non-febrile animals, although this method of temperature collection is accompanied by efficiency and safety limitations. Newer technologies such as infrared thermal imaging cameras are being developed and tested as possible alternatives to rectal temperatures. The objectives of this study were to compare a prototype non-contact thermography device (NCT) to a traditional FLIR® thermal imager (FLIR Systems Inc., Wilsonville, OR) and to determine the relationship between rectal and ocular temperatures as indicators of health status. To accomplish this, 91 measurements were taken on sedentary horses (2-15 yr; 357 to 540 kg) at a distance of 1 m with the FLIR® and NCT at the: medial canthus (MC), ocular globe (OG), and lateral canthus (LC) of the eye. Rectal temperatures were obtained for a standardized body temperature. Relationships between measurements were analyzed using the PROC CORR procedure of SAS. A moderate relationship was observed between the NCT:FLIR® at the OG (r = 0.51; P ≤ 0.05) and the LC (r = 0.54; P ≤ 0.05); however, only a weak relationship was detected at the MC (r = 0.08; P ≤ 0.05). When compared to rectal temperatures, the FLIR®:Rectal relationship was stronger at the MC (r = 0.42; P ≤ 0.05) and LC (r = 0.33; P ≤ 0.05) than the NCT:Rectal relationship (r=0.02 and r = 0.28 respectively; P ≤ 0.05). Conversely, the NCT:Rectal correlation was stronger at the OG (r=0.41; P ≤ 0.05) than the FLIR®:Rectal relationship (r = 0.31; P ≤ 0.05). The results of this study indicate that the two thermography devices function similarly to one another, but their utility for accurately determining body temperature remains limited. However, both technologies may prove useful as an efficient preliminary screening device of potentially ill horses.