Oxytocin facilitates behavioural, metabolic and physiological adaptations during lactation.

The aim of this article is to propose that oxytocin not only stimulates milk let down, but also adapts behaviour and physiology to facilitate lactation in mammals including dairy cattle. Circulating oxytocin as well as neurogenic oxytocin participates in these regulatory processes. In short, oxytocin stimulates maternal interaction and attachment between mother and young. It also participates in the metabolic prerequisites for milk production by e.g. stimulating glucagon release and thereby, mobilisation of glucose. Digestive and anabolic aspects of metabolism are also stimulated, e.g. by increased vagal nerve activity. Adaptations consistent with an antistress like pattern are also induced. Cortisol levels are decreased as well as blood pressure, and behaviours characterised by calm, reduced levels of anxiety and more social activity are promoted. These effects seem to be present in monogastric animals as well as in ruminants. The expression of various aspects of these adaptations vary according to the special needs and living environmental circumstances of different species. The mechanisms behind the effect spectrum of oxytocin are being explored in other experimental models. A second aim of this paper is to suggest that efficiency of lactation can be promoted by facilitating oxytocin release in connection with milking by enhancing the amount of sensory stimulation.