Non-contact infrared thermometers have been considered as an alternative, providing quick and convenient temperature readings without direct contact. However, these thermometers offer a rapid assessment of surface temperature, and their readings may not closely reflect the core body temperature compared to rectal thermometers. Environmental conditions and the presence of a thick hair coat can further influence their accuracy.
The research, conducted by Leslie Easterwood and Noah D. Cohen from the Department of Large Animal Clinical Sciences at Texas A&M University, involved a comparison of rectal temperatures with recordings obtained using a non-contact infrared thermometer in 142 Quarter Horse horses and 34 Quarter Horse foals. Measurements from the non-contact infrared thermometer were collected from the forehead or neck, while rectal temperatures were recorded separately for each horse and foal.
The study revealed that the readings obtained by the non-contact infrared thermometer demonstrated good reliability in terms of measurement repeatability. However, these readings did not align well with rectal temperatures. Notably, there was a substantial negative bias, with adult horses displaying non-contact infrared thermometer readings nearly 2°F lower than rectal temperatures. This difference was more pronounced in foals, where the average difference exceeded 3°F.
In conclusion, the researchers assert that the substantial and inconsistent bias observed with the non-contact infrared thermometer indicates that these devices may not be a suitable substitute for rectal thermometry when aiming to obtain valid estimates of core body temperature in horses.
For more details see:
Agreement of Temperatures Measured Using a Non-Contact Infrared Thermometer With a Rectal Digital Thermometer in Horses,
Leslie Easterwood, Noah D. Cohen
Journal of Equine Veterinary Science,(2023) Vol 123,104243,