ヤギにおける輸送シュミレーションおよび実際の輸送ストレスの発現について

To elucidate a possibility of the participation of sensory-psychological pathway to respond to the stressors at the starting phase of transportation, a swing model experiment and real transportation were conducted using three naive male Tokara goats with indwelling catheters installed in jugular and femoral veins. With the swing model experiment, the caged goat was exposed to 6 repetitions of a module of 15min constituting 10min of irregular and intense movements and 5min of regular movement. With the real transportation the caged animal was loaded on a truck and journeyed along the highway for 3h. During the swing movement, the experimental animal showed scrambling and nervous behaviors. Immediately from the beginning of the first module of the swing, an acute and transitory tachycardia associated with the irregular and intense movements were observed. In contrast to heart rate, respiration rate did not show any association with the swing movements but with the lapse of time of swing treatment. At 30min from the beginning, plasma concentrations of cortisol and glucose had elevated sharply to 4 and 3 times higher than basic values, respectively. At the end of swing, cortisol showed 5 times higher than the basic value and glucose 4 times as high. They returned to the basic values 3h after the termination of the swing movement. The number of eosinophils was decreased by the swing and showed the minimum at 4.5h from the beginning of the swing and then returned to the basic value 12h after the termination of the swing movement except one animal out of the three. The total number of white blood cells gradually increased from the beginning of the swing and reached the two peaks after 3h and 12h from the end of the swing movement. Though the magnitude and duration of the responses were more remarkable during the truck transportation, plasma concentrations of cortisol and glucose showed essentially the same responses as in the swing model experiment. The decrease in the number of eosinophils was observed in two goats out of three from the beginning of the truck journey and then returned to the basic value 15h after the termination of the truck journey. The total number of white blood cells increased from the beginning of the transportation and showed the peak at 2h from the beginning. The timing of rises of plasma cortisol, glucose and the total number of white blood cells, and decrease in the number of eosinophils was synchronized closely at the beginning of the experiments and these responses were able to be identified in both the swing model and real transportation. The behavioral, cortisol and hematological responses at the beginning of the present experiments suggest that the animal was thought to be in a startle reaction with fear and anxiety to the unfamiliar treatments and environment, indicating the participation of sensory-psychological pathway.