Abstract
Most studies on guide dogs for the blind were conducted to investigate the appropriateness of the animals, including in terms of their breeding, constitution, and temperament. However, research to comprehend the stress status of guide dog candidates in response to their training has been unclear. In this study, the levels of serum cortisol, nerve growth factor (NGF), and magnesium ion (Mg2+) levels of guide dog candidates during the three training stages-the elementary, intermediate, and advanced classes-were examined. Dogs were classified based on the contents of the classes and period during the training in which they were subjected. Since the dogs in the elementary class had the lowest serum NGF and Mg2+ levels, they were understood to be under mental stress and to be unfamiliar with their new surroundings. In contrast, the serum NGF and Mg2+ levels were high in the dogs in the advanced class, though they were demonstrated to be mentally stable and acclimated to their environment. Additionally, they were almost free from the stress caused by daily life, since they had the lowest serum cortisol levels. The status of each dog was plotted on a map consisting of 2 axes representing the serum NGF and Mg2+ levels with high or low cortisol levels. Plots could be divided into three domains corresponding to the elementary, intermediate, and advanced classes. Therefore, for working dogs, serum NGF and Mg2+ levels in addition to serum cortisol levels may be important factors to comprehend the type of stress situation that each dog was in.