REPRODUCTION AND PERINATOLOGY IN COMPANION ANIMALS INVESTIGATED BY USE OF NONINVASIVE MATRICES

Reproduction in companion animals is a topic of growing interest for scientific research, but knowledge about some aspects is still lacking. This is likely due to the need of collecting a large number of serial samples in order to perform longitudinal studies of the longer-lasting reproductive phases, which is now incompatible with the current concept of animal welfare, according to which any distress must be avoided, especially where pregnant and neonatal subjects are concerned. For these reasons, complying with the need of respecting animal welfare and aiming to study reproductive phases that are still incompletely explored in companion animals, the project lines of the present PhD thesis were focused on three crucial phases of reproduction: pregnancy and post-partum, perinatology and puberty. This was achieved by using matrices, like coat and the claws, and, to a lesser extent, fetal fluids obtained by noninvasive sampling. The sudden Covid-19 pandemic and the consequent lockdown rules have partially impaired the sample collection and laboratory analyses, but some interesting and satisfactory data were provided nonetheless. In the pregnancy and post-partum study, the results showed changes in the concentrations of cortisol (C) in coat from mating to 60 days post- partum, in line with what was reported for cats, suggesting that canine maternity could be considered as a challenge for the bitches, and dehydroepiandrosterone-sulfate DHEA(S) was also analyzed. About perinatology, the claws concentrations of C, DHEA(S), E2 and T tended to decrease from birth until 60 days of age, adding precious information about the perinatal physiology. In fetal fluids, leptin amniotic concentrations were higher in smaller-seized breeds, highlighting the role of breed body-size in affecting the intrauterine fetal metabolism. In the puberty study, in cats 17β-estradiol (E2) and testosterone (T) concentrations were assessed in coat and dewclaws. The concentrations of T in coat significantly differed between pubertal males and females and between gonadectomized males and females. The concentrations of T in coat were higher in pubertal than prepubertal male cats. In dogs, the analyses of the concentrations of C, DHEA(S), T and E2 in coat showed lower DHEA(S) concentration in pubertal than prepubertal and gonadectomized female dogs. In males, T concentrations in coat were higher in pubertal than prepubertal dogs, and C concentrations in coat were higher in pubertal than prepubertal and gonadectomized dogs, suggesting that pubertal status leads to a higher activation of the HPA axis in male dogs. The results shown in the present thesis evidenced the usefulness of these matrices for longitudinal and long-term hormonal studies of reproduction in dogs and cats, providing useful data about crucial reproductive phases and new interesting insights. Further investigations are needed to better understand some pending questions about the use of these matrices.