Cortisol, DHEA and DHEAS concentrations in claws collected by newborn dogs during the first 60 days of age: preliminary results

Despite the extremely high perinatal losses in dogs, canine perinatology remains mostly unknown because of the difficult blood samples serial collection in newborns, and also because of ethical limitation. Coat and claws can be collected without invasiveness and are suitable for long term retrospective measurement of hormones accumulation, in dogs (CIT). Among several parameters, cortisol (C), dihydroepiandrosterone (DHEA) and dihydroepiandrosterone sulphate (DHEAS) are crucial for the fetal to neonatal transition and for neonatal adaptation. This study was aimed to preliminary investigate the cortisol, DHEA and DHEAS concentrations in claws, collected without invasiveness in 7 newborn dogs at birth, and at 30 and 60 days of age. Puppies, from a single litter, were born by elective Caesaeran section at term of a normal pregnancy. At birth puppies were mature, viable, healthy and normal weighed; they remained healthy and with normal development during the following 60 days. The claws of the four legs were trimmed at birth, and trimmed again, collecting only the claws regrowth, after 30 and 60 days. For each sampling time, individual pool of claws were stored until analysis by RIA. Cortisol decreased from 55.1±24.74 pg/mg at birth to 22.2±7.87 (p<0.01) at 30 days, and to 9.1±3.36 at 60 days (p<0.0001); DHEA decreased from 452±212.30 pg/mg at birth to 195±252.04 at 30 days, and to 43±9.13 at 60 days (p<0.01), while DHEAS decreased from 208±95.35 pg/mg at birth to 135±79.44 at 30 days, and to 45±13.98 at 60 days (p<0.01). These results showed that the highest accumulation occur during the second half of gestation, during the fetal development, but the still high C, DHEA and DHEAS levels at 30 days, seems to suggest also a role of these hormones in the period of long neonatal adaptation in the altricial-inept progeny typical of dogs.