Validation of Topically Placed Merck Bio-Thermo Microchips for Estimating Core Body Temperature in Dry Holstein Cows

Abstract

Accurate measurement of core body temperature is essential for monitoring health, stress, and productivity in dairy cattle (Ibáñez et al., 2023). Traditional methods, such as rectal thermometry, provide reliable measures but are invasive, labor-intensive, and impractical for continuous monitoring of large herds (Ibáñez et al., 2023). Vaginal thermometry using modified controlled internal drug release (CIDR) devices can provide continuous data but is unsuitable for calves. Microchips capable of recording body temperature (e.g., Merck Bio-Thermo) have been used in livestock, particularly equines, but require subcutaneous implantation, which is invasive and not suitable for removal in food animals. Topical microchips may offer a noninvasive, low-stress alternative for repeated temperature monitoring, but their ability to accurately reflect core body temperature in dairy cattle is not well established. This study evaluates the validity of surface-mounted Merck Bio-Thermo microchips in five dry Holstein cows. Microchips were attached to the ear, inner front leg, and tail base, and temperatures were recorded hourly for four six-hour trials. Vaginal core temperatures were simultaneously recorded using CIDR-held data loggers. Ambient temperature and relative humidity were measured to assess environmental effects on surface readings. Temperature data were analyzed using regression models to evaluate the relationship between microchip and core temperatures. Microchip readings are expected to show moderate correlation with core temperatures, with some variation due to anatomical placement and environmental conditions. Findings from this study will help determine whether topically placed microchips provide a practical, noninvasive, and labor-efficient method for continuous monitoring of body temperature in dairy cattle.No embargoAcademic Major: Animal Science