The usefulness of claws collected without invasiveness for cortisol and dehydroepiandrosterone (sulfate) monitoring in healthy newborn puppies after birth

Despite the high rates of perinatal mortality in dogs, the study of canine perinatology did not receive strong scientific interests until recently, probably due to the difficulties in studying long term changes evaluations without incur with ethical issues. In the recent years, however, the usefulness of new matrices, such as the claws, collectable without invasiveness and providing information about a long-term, retrospective window of time were reported to be a suitable tool for the study of canine perinatology in spontaneously dead puppies. The present study was therefore aimed to assess the usefulness of claws as matrices collectable without invasiveness for the study of immunoreactive cortisol and dehydroepiandrosterone (sulfate) in alive puppies at birth, at 30 and at 60 days of age. Beside the effect played by the sampling time, the possible effect of type of birth, vaginal delivery (VD) or elective Cesarean section (CS), as well as of some other maternal or neonatal factors was assessed. The results showed a significant decrease of both hormones from birth to 30 and to 60 days of age (p < 0.001) and from 30 to 60 days of age (p < 0.05), and highlighted, for both hormones, the influence of the type of birth, with newborns born by VD having higher concentrations of immunoreactive cortisol (p < 0.01) and dehydroepiandrosterone (sulfate) (p < 0.001) than the newborns born by elective CS in collections made at birth. No other significant effect was detected. The study confirmed the usefulness of claws as matrix collectable without invasiveness for the retrospective, long-term assessment of hormonal changes in alive newborn puppies and that both hormones declined from birth to 60 days of age. The differences between puppies born by vaginal delivery or elective Caesarean section suggest a possible different HPA activation in puppies born by the two types of birth.