The Influence of Oxytocin on Maternal Care in Lactating Dogs

SIMPLE SUMMARY: The role of oxytocin in regulating uterine contractions and milk ejection has been largely outlined. However, its central functions in neuromodulating the onset and maintenance of maternal care in domestic dogs are still unclear. Since the mother–infant interactions have a severe impact in determining later behavior in mammals, this study intended to investigate the possible correlation between salivary oxytocin and maternal care in 25 lactating dogs. Only a negative correlation between salivary oxytocin and sniffing/poking behavior was found. Therefore, salivary oxytocin cannot be considered a strong predictive biomarker of the quantity of maternal care in dogs. Moreover, the percentage of male puppies showed a positive correlation with salivary oxytocin and lateral nursing, which suggests a sex-biased parental investment in this species. These findings can be considered the first piece of the oxytocin puzzle in regulating dog–pup interaction. ABSTRACT: In recent years, many studies on the role of oxytocin (OXT) in the onset of parental care, regulation of social bonding, and modulation of the emotional state have been published. However, its possible regulation of maternal behavior in lactating dogs has not been investigated yet. For this reason, the present study aimed at assessing potential correlations between salivary oxytocin and maternal behavior in 25 lactating Labrador Retriever dogs. Salivary concentrations of OXT (sOXT) were unrelated to the amount of maternal care except for a weak negative correlation with sniffing/poking behavior. Moreover, sOXT was positively correlated with the percentage of male puppies. Sniffing/poking behavior, in turn, was positively correlated with the duration of time the mothers spent out of the whelping box, while the number of male puppies showed a positive correlation with lateral nursing, a position known to provide puppies the easiest access to the milk. Taken together, these results suggest that sOXT may not be strongly associated with maternal care dynamics but could be correlated with sex-biased parental investment in dogs.