In a joint research with the Japan Guide Dog Association, a research group led by Miho Nagasawa of Azabu University analyzed glucocorticoid secretion during the breeding process of guide dogs. He showed that he adapted quickly while showing an appropriate stress response to the change, and that he had less daily fear response.
Glucocorticoids are steroid hormones produced in the adrenal cortex and are elevated during stress.It is generally said that high quality mothers' rearing behavior reduces glucocorticoid secretion in offspring and weakens post-growth aggression and fear response, but the association was unclear.
In this study, we targeted 425 (63) puppies born and recorded the rearing behavior of 21 mother dogs.In addition, the values of urinary cortisol (a type of glucocorticoid) in mother dogs and puppies were measured.
As a result of the analysis, the puppies that were well-bred by their mothers had higher cortisol basal levels at 5 weeks of age, and at 1 year of age, the stress response to the new environment (admission to the guide dog training center) increased. , Stress tolerance (recovery from stress) was also found to improve.
The research group has already found that there is a "stress refractory period" in which glucocorticoids do not rise under stress during the first 4 weeks of life in dogs, and that basal cortisol levels rise shortly before the end of the refractory period.It was also known that the presence of the mother extended the refractory period.Therefore, the increase at 5 weeks of age is considered to be an extension of the stress refractory period due to the good breeding behavior of the mother dog.
Since humans also have a stress refractory period, this result has important implications for human development.He also points out that it encourages reconsideration of the role of glucocorticoids in living organisms.
Paper information:[Hormones and Behavior] Basal cortisol concentrations related to maternal behavior during puppy development predict post-growth resilience in dogs
