Determination of the suitable time for infrared thermography-based tick identification

Abstract

Accurate quantification of tick infestation is crucial for effective tick control in livestock, yet conventional visual counting methods are constrained by observer bias, hair cover, and environmental influences. Infrared thermography (IRT) offers a non-invasive alternative for tick detection based on thermal contrast between ticks and host skin; however, the optimal time for image capture under tropical conditions remains unclear. This study aimed to identify the most suitable time window for IRT-based tick identification and quantification in crossbred cattle. Five naturally tick-infested crossbred cattle (12-24 months old) maintained under uniform management conditions and without acaricide treatment were monitored. Thermal images were captured hourly from 6:00 A.M. to 12:00 noon using a high-resolution infrared camera. Tick counts were obtained by visual inspection and automated analysis of IRT images in ImageJ, with emphasis on skin and tick-surface temperature differences across body regions. Skin surface temperature was significantly higher (p < 0.01) than tick surface temperature in the inner thigh, perineal, and dewlap regions, with the greatest temperature difference observed in the inner thigh (2.5±0.15 °C). Automated IRT analysis showed maximum tick detection between 6:00 and 10:00 A.M, followed by a decline toward mid-day as ambient temperature increased and thermal contrast decreased. The study concludes that early morning (6:00-10:00 A.M.) is the most suitable time for IRT image capture for accurate tick identification and quantification in crossbred cattle under tropical climatic conditions. IRT combined with automated image analysis represents a reliable tool for precision tick surveillance.