2026/07/28 by Sahar Rostami, Kimberly A. Woodruff, Abigail McBride +1
Agricultural and Biological Sciences · Medicine · #Effects of Environmental Stressors on Livestock #Infrared Thermography in Medicine #Thermal Regulation in Medicine
paper · doi:10.2460/ajvr.26.05.0212
openalex publication_date 2026/07/28 · openalex created_date 2026/07/29 · openalex updated_date 2026/07/30
Objective: To establish a reference interval (RI) for eye temperature (ET) in preweaned dairy calves and to identify the physiological, environmental, and management-level factors that influence ET under field conditions. Methods: Calves (n = 21) were housed in individual hutches, categorized by the presence or absence of shade. Eye temperature readings were collected 3 times per visit, during both morning and afternoon periods. The maximum temperature of either eye was the primary outcome. Rectal temperature (RT) was obtained for comparison. Factors affecting ET and RT were evaluated using a linear mixed-effects model. The RI for ET and RT was estimated via multiple outputation. Results: The RI for ET was 37.5 °C to 41.3 °C. Eye temperature was positively associated with RT (β = 0.5 °C) and was higher in female calves (β = 0.3 °C). Calves in unshaded hutches exhibited higher temperatures (β = 0.8 °C) than those in shaded housing, and afternoon measurements were higher (β = 0.2 °C). Temperature-humidity index (β = 0.04) and wind speed (β = -0.1) were also associated with ET. With the exception of calf sex, similar environmental and management factors affected RT. Conclusions: Eye temperature and RT were modulated by the environmental and individual animal factors. Therefore, interpreting ET requires consideration of these factors similar to interpreting RT. Clinical Relevance: This study provides the foundational baseline for ET under farm conditions, enabling clinicians to differentiate normal physiological variation from potential pathological variations, provided the environmental context is considered.