The effect of amniotic fluid olfactory stimulation on salivary oxytocin in anestrus female dogs

Amniotic fluid is known to attract mammals around parturition, but its hormonal impact through sensory stimulation remains unclear. This study investigated the impact of amniotic fluid olfactory stimulation on salivary oxytocin (sOXT) in Labrador Retriever. Dogs were divided into a control group (CG, n = 9) receiving water, and a treatment group (TG, n = 8) receiving amniotic fluid. Saliva samples were collected from each dog before (T0) and 10 minutes after administration (T1). Multiparous bitches had significantly higher sOXT levels (mean ± S.D. = 114.1 ± 16.2 pg/ml) than primiparous ones (mean ± S.D. = 93.6 ± 16.38 pg/ml) at T0 (t = 2.56; p = 0.021). However, no significant differences in sOXT concentrations were found between CG and TG at either time point, nor within groups between T0 and T1. Although not statistically significant, yellow-coated dams showed higher sOXT levels (108.1 ± 20.22 pg/ml) compared to chocolate (100.6 ± 22.98 pg/ml) and black (106.2 ± 17.45 pg/ml) ones. A positive correlation was observed between age and sOXT at T0 (r = 0.445; p = 0.035). These results suggest that amniotic fluid alone does not increase sOXT and is likely insufficient to induce maternal behavior in anestrus dogs.