Body Temperature Responses During Phases of Work in Human Remains Detection Dogs Undergoing a Simulated Deployment

SIMPLE SUMMARY: Working dogs are frequently transported via crates in vehicles to various deployment scenarios. Body temperature increase associated with exercise is common but has not been assessed throughout the entire work cycle for dogs during a deployment scenario. We measured continuous temperature changes for dogs throughout an entire day of search operations including each stage of the work cycle, namely waiting-to-work, active work, and post-work recovery. We found that dogs did not increase in temperature while waiting-to-work but temperature did increase during the period of active work. Additionally, when dogs were returned to vehicles for crate and rest during the post-work recovery period, body temperatures continued to increase. We suggest that post-work recovery in the vehicle should be further investigated to better manage dogs through continuing search operations. ABSTRACT: Body temperature responses were recorded during phases of work (waiting-to-work in close proximity to search site, active work in a search site, and post-work recovery crated in vehicle) in human remains detection dogs during search training. State or federally certified human remains detection dogs (n = 8) completed eight iterations of searching across multiple novel search environments to detect numerous scent sources including partial and complete, buried, hidden, or fully visible human remains. Internal temperature (Tgi) of the body was measured continuously using an ingestible thermistor in the gastrointestinal tract. Mean total phase times were: waiting-to-work: 9.17 min (±2.27); active work: 8:58 min (±2:49); and post-work recovery: 24:04 min (±10.59). Tgi was impacted by phase of work (p < 0.001) with a small increase during active work, with mean peak temperature 39.4 °C (±0.34 °C) during that period. Tgi continued to increase for a mean of 6:37 (±6:04) min into the post-work recovery phase in the handler’s vehicle with a mean peak Tgi of 39.66 °C (±0.41 °C). No significant increase in temperature was measured during the waiting-to-work phase, suggesting behaviors typical of anticipation of work did not appear to contribute to overall body temperature increase during the waiting-to-work recovery cycle. Continued increase of gastrointestinal body temperature several minutes after cessation of exercise indicates that risk of heat injury does not immediately stop when the dog stops exercising, although none of the dogs in this study reached clinically concerning body temperatures or displayed any behavioral signs suggestive of pending heat injury. More work is needed to better understand the impact of vehicle crating on post-work recovery temperatures in dogs.