Use of Thermography on Dairy Goats Under Elevated Ambient Temperature and Udder Inflammation

Infrared thermography has been proposed as a non-invasive tool for mastitis detection in dairy ruminants; however, the extent of environmental confounding and diagnostic performance in small ruminants remain poorly characterized. This study evaluated udder thermography in dairy goats through correlation analysis under winter and summer conditions, and an experimental intramammary inflammation challenge using Staphylococcus aureus lipoteichoic acid, with receiver operating characteristic analysis using somatic cell count >1500 × 103 cells/mL as the reference standard. Strong positive correlations between ambient temperature and udder surface temperatures intensified substantially from winter to summer, while surface temperatures showed weak or absent correlations with rectal temperature. Experimental inflammation induced a 12-fold increase in somatic cell count (305 vs. 3658 × 103 cells/mL, p < 0.001); however, thermographic responses remained minimal and spatially inconsistent, with area under the curve values approximating 0.5 and weak correlations between thermographic measurements and somatic cell count. Environmental temperature variation and physiological thermoregulatory adjustments substantially exceeded the minimal thermal signal generated by intramammary inflammation, limiting diagnostic utility. Infrared thermography showed poor diagnostic utility for detecting experimentally induced intramammary inflammation in dairy goats under the tested conditions.