Date of Award
Master of Science
Ten canines were utilized in a repeated design to examine the effects of stress associated with work on activity expenditure, core body temperature, and salivary cortisol. However, only eight canines had valid data results due to the ninth canine having a metabolic syndrome that was not diagnosed. The tenth canine was removed from the study prior to initiation of the search scenario due to aggression. The objective was to observe the impact of stressors associated with work on activity expenditure, core body temperature, and salivary cortisol in human remains detection canines. Nine canines were randomly assigned to 1 of 3 simulated search sites which each had two repetitions 1A) RU (rubble area with two concealed partial cadavers); 1B) RU (open crop field with one concealed partial cadaver); 2A) WA (wooded area with two concealed partial cadavers elevated off the ground); 2B) WA (wooded area with two concealed partial cadavers); 3A) MC (mass casualty area with eight exposed full body cadavers); 3B) MC (mass casualty area with five buried full body cadavers). Canines searched for an average of 90 minutes at each site which was then followed by a 10 minute rotation period where canines randomly rotated to one of the other two sites. Upon completion of the third site, canines repeated the first site location. There was a 69 minute rest period between the second and third rotation. Canines were rotated through search sites such that one canine was actively working (AW), the next canine was waiting to work (WW) and was exposed to visual and auditory stimulation in preparation for work and the third canine in the rotation was not working (NW) and crated in the handler’s vehicle with no visual or auditory stimulation associated with work 100 feet from WW area. Total activity expenditure was not influenced by site (P = 0.89) which may indicate detection canines were efficient in expending energy during this study. This correlated with the walk activity expenditure by site as it did not differ based on site (P = 0.16). The canines expended a similar amount of walk energy at each site and this may demonstrate that canines spent more time searching and in scent of the cadaver(s). Conversely, run activity expenditure was influenced by site (P = 0.03), specifically RU site was greater than MC site. When further comparison of the RU repetitions was analyzed, the second repetition was greater than the first in run activity expenditure (P < 0.0001). Canines at the RU site during the second repetition had an easier ability to run compared to the first repetition because of the nature of the site. Total activity expenditure was influenced by rotation (P = 0.04) but was not influenced by rotation within site (P = 0.17). The first rotation was greater than the fourth rotation which may indicate a psychological stressor such as anticipation of the work and possible acclimation of the site. The fourth rotation was at the same location site as the first rotation and canines did not have the novelty of the site as a psychological stressor during the fourth rotation. Canines that did not have exposure to full body cadavers prior to this study did not have greater total activity expenditure (P = 0.46) at the MC site compared to canines that did have exposure to full body cadavers prior to the study. There was an effect of phase on core body temperature (P = 0.0003). However, 95.3% of canines had their core body temperature peaked in the NW phase directly after the AW phase. Which demonstrates that core body temperature continued to increase post exercise. There was also a plateau in the core body temperature for 18 minutes post exercise which could indicate peripheral vasodilation. Attenuation of core body temperature occurred 37 minutes after cessation of the AW phase. There was an effect of site (P < 0.0001), rotation (P < 0.0001), and rotation within site (P < 0.0001) on core body temperature. This may indicate that there was a boundary layer stimulus that acted as a psychological stressor. In addition, the second and third rotation were greater than the first and fourth rotation which is most likely due to the increase in humidity during the second rotation. Core body temperature was impacted by total activity expenditure (P < 0.0001) which is to be expected with increased exercise, core body temperature increases. Salivary cortisol was influenced by site (P = 0.003), specifically the WA site was greater than the MC and the RU site. The WA site may have had a stronger psychological stressor with the tree lines compared to the MC and the RU sites. Rotation within site did impact salivary cortisol (P < 0.0001). However, rotation alone did not influence salivary cortisol (P = 0.42). Core body temperature did not impact salivary cortisol (P = 0.18). Total activity expenditure did not affect salivary cortisol (P = 0.73). Salivary cortisol and age of canine did display a pattern (P = 0.003). Salivary cortisol and exposure to prior full body cadaver did not displayed a pattern (P = 0.78). Based on these results, some physical stressors such as site, rotation, and exercise impacted activity expenditure, core body temperature, and salivary cortisol. This thesis provides limited data dissemination on three physiological parameters that may be impacted on independent variables that are associated with search scenario work. More research is needed to confirm if these specific stressors observed impact activity expenditure, core body temperature, and salivary cortisol in human remains detection canines.
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