SOME PERINATAL ENDOCRINE AND MORPHOLOGICAL ASPECTS OF CANINE SPECIES

Despite the huge literature about dog medicine, the perinatal period of growth and development and possible perturbations of the health of fetuses and newborns are still scarcely investigated, but with a recent, increasing scientific interest. The present thesis was therefore aimed to investigate some perinatal aspects of canine perinatology. Firstly, the study focused on the presence of some growth and metabolic factors and protective substances in dog fetal fluids at term of normal pregnancy. About growth and metabolic factors, the first study showed that insulin-like growth factors I (IGF-I) were higher in amniotic (AM) than allantoic (AL) fluid and the effect of breed size, even if opposite, on both IGF-I and non-esterified fatty acids (NEFA) was evidenced. The findings suggested that AM IGF-I could be used as an indicator of growth potential in canine species, whereas AM NEFA could work as a marker of fat mobilization for an energy request. The second study on fetal fluids, aimed to assess AM and AL IgG and lysozyme concentrations, documented higher IgG levels in AM than AL fluid, as a consequence of a supposed direct fetal IgG production, whereas no significant differences were found in lysozyme values between the two fluids. Maternal parity was demonstrated to affect IgG concentrations. A second area of study was the assessment of newborns hair and nails usefulness as the newest non invasive matrices for a long-term retrospective investigation of the Hypothalamic-Pituitary-Adrenal axis activation, by cortisol (C) concentrations analysis. The study evidenced that C was detectable in both matrices, with significant higher values in premature puppies compared to term-born dead puppies or puppies dead within the first 30 days of age. Furthermore, because of the newborn puppy high susceptibility to bacterial infection, often followed by death, the fourth study investigated the bacterial involvement in canine neonatal mortality, demonstrating that bacterial infections, above all by E. coli, alone or in association with other bacteria, represent an important cause of neonatal losses. In addition, the study highlighted the importance of the antimicrobial susceptibility test in case of suspected neonatal bacterial infection for a more targeted therapy of surviving litter-mates and for a better management of further gestations in bitch with previous neonatal mortality. The last study was designed to investigate some aspects of skeletal development during the neonatal period in the attempt to provide further knowledge about the first month of skeletal growth in puppies, but also aimed to assess the possible use of some radiographic, morphometric, and anatomic parameters for the age estimation in newborn dogs. The study proved that the neonatal growth occurs gradually as the age progresses, and simultaneously in the body, limbs, and skull. The radiographic evaluation of the ossification centers appearance resulted a useful tool to estimate the neonatal age in puppies, even if during the first 14 days of age significant skeletal changes were not observed. In this respect, the radiographic and anatomic measures of the hindlimb long bones and skull length seem to provide better guarantees; specifically, the neurocranium width as well as tibial and femoral lengths resulted the most correlated measurements with the age. Thus, in the future radiographic and/or anatomical morphometry of limbs and skull could become the best tool for neonatal age estimation.