Equine study finds ocular thermography overestimates rectal temperature

Lacrimal caruncula thermography doesn’t appear ready to replace rectal temperature measurement in horses, according to a new Equine Veterinary Journal study. In the study, Ömer Tarık Orhun and colleagues found that infrared thermography of the lacrimal caruncula consistently overestimated rectal temperature across two camera types, and agreement worsened as measurement distance increased. The UTi165A camera performed better at 0.5 meters than the comparison device, but neither camera was accurate enough to serve as a stand-in for standard rectal thermometry. That finding lines up with earlier equine research showing that non-contact infrared methods can be repeatable without being clinically interchangeable with rectal temperature, and that thermographic readings are highly sensitive to camera performance and testing conditions. (pubmed.ncbi.nlm.nih.gov)

Why it matters: For veterinary professionals, the takeaway is practical: ocular thermography may still have value for welfare, stress, or screening applications, but it shouldn’t be treated as a reliable proxy for core body temperature in horses. Prior work has already shown that environmental factors such as airflow can shift thermographic readings, and reviews of equine temperature monitoring note that rectal temperature remains the routine clinical standard even as less invasive tools are explored. In other words, convenience and safety advantages haven’t yet overcome the accuracy gap. (pubmed.ncbi.nlm.nih.gov)

What to watch: Watch for follow-up work on standardized imaging protocols, shorter capture distances, and whether newer devices or AI-assisted image analysis can improve agreement enough for screening use, even if not for diagnosis. (link.springer.com)