Agreement of Temperatures Measured Using a Non-Contact Infrared Thermometer With a Rectal Digital Thermometer in Horses.
Authors: Easterwood Leslie, Cohen Noah D
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Non-Contact Infrared Thermometry in Horses Rectal thermometry remains the gold standard for assessing equine core body temperature, yet presents practical challenges including safety risks and the time required to obtain readings from groups of animals or fractious individuals. Easterwood and Cohen evaluated whether non-contact infrared thermometers (NCITs) could provide a reliable alternative by comparing forehead or neck measurements against simultaneous rectal digital readings in 142 healthy horses and 34 foals. Whilst the NCIT demonstrated excellent repeatability when used consistently, a substantial and systematic negative bias emerged: readings averaged nearly 2°F (approximately 1.1°C) lower than rectal values in adult horses and over 3°F in foals, with considerable variation between individual animals. These findings indicate that NCITs cannot currently be recommended as a substitute for rectal thermometry in clinical practice, as the magnitude and inconsistency of the bias would render temperature trends unreliable and risk masking febrile responses. Until device calibration or alternative measurement sites are validated in febrile horses, practitioners should continue relying on rectal thermometry when accurate core temperature assessment is diagnostically essential, whilst recognising that NCITs may have value only for rapid screening purposes where approximate data is acceptable.
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Practical Takeaways
- •Do not rely on non-contact infrared thermometers as a replacement for rectal thermometry when assessing horse health or fever, as they significantly underestimate core body temperature
- •While non-contact thermometers are convenient and safer for handler and horse, their consistent negative bias means they cannot provide clinically valid temperature readings for diagnostic or biosecurity purposes
- •Rectal digital thermometry remains the standard method for accurate equine temperature assessment despite its practical limitations
Key Findings
- •Non-contact infrared thermometers showed good reliability/repeatability but demonstrated a large negative bias of nearly 2°F compared to rectal digital thermometers in adult horses
- •Foals showed an even larger negative bias of >3°F when using non-contact infrared thermometers versus rectal thermometry
- •The large and inconsistent bias observed makes non-contact infrared thermometers unsuitable as a substitute for rectal thermometry for measuring core body temperature in horses