| Budget Amount *help |
¥2,756,000 (Direct Cost: ¥2,120,000、Indirect Cost: ¥636,000)
Fiscal Year 2010: ¥1,313,000 (Direct Cost: ¥1,010,000、Indirect Cost: ¥303,000)
Fiscal Year 2009: ¥1,443,000 (Direct Cost: ¥1,110,000、Indirect Cost: ¥333,000)
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| Research Abstract |
Dogs'adaptability to stress is an important factor for socialization to human society. However, the developmental characteristics of neuroendocrine responses to stress have not been fully clarified in dogs. In the present study, we investigated dogs' neuroendocrine responses to stress in both socialization and peripubertal periods, and conducted a correlation analysis of them between the two periods. Subjects were Labrador Retrievers in the Japan guide dog center. At first, we applied a brief stress to pups at4,5,6or7weeks after birth by 5-min maternal separation and evaluated the stress response by an elevation of urinary cotisol levels. The pups were then raised by puppy raisers until the age of1year. The adaptability to stress in the peripubertal period was then assessed by urinary cortisol levels during2weeks after transfer into the training center from the puppy raisers' houses. As results, urinary cortisol levels were not increased by maternal separation in almost all pups at4weeks of age. Thereafter, significant stress responses were observed with individual variation. Interestingly, littermates showed the same tendency of urinary cortisol dynamics against stress in their peripubertal period. Further, we found a significant negative correlation of stress responses between socialization and peripubertal periods ; when the stress response following maternal separation was high at7weeks of age, the increased urinary cortisol levels after transfer to the training center tended to decrease quickly. These findings suggest that the stress hyporesponsive period terminated at around4weeks of age in dogs, and the adaptability to stress in peripubertal period was influenced by the maternal environment and partly programmed until7weeks of age. The ability to predict the dog's adaptability to stress at an early age would be of great value in planning future training programs or selecting candidates as working dogs.
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