Oxytocin facilitates behavioural, metabolic and physiological adaptations during lactation

The aim of this article is to propose that oxytocin not only stimulates mil k let down, but also adapts behaviour and physiology to facilitate lactatio n in mammals including dairy cattle. Circulating oxytocin as well as neurog enic oxytocin participates in these regulatory processes. In short, oxytoci n 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. Dig estive and anabolic aspects of metabolism are also stimulated, e.g. by incr eased vagal nerve activity. Adaptations consistent with an antistress like pattern are also induced. Cortisol levels are decreased as well as blood pr essure, and behaviours characterised by calm, reduced levels of anxiety and more social activity are promoted. These effects seem to be present in mon ogastric animals as well as in ruminants. The expression of various aspects of these adaptations vary according to the special needs and living enviro nmental circumstances of different species. The mechanisms behind the effec t spectrum of oxytocin are being explored in other experimental models. A s econd aim of this paper is to suggest that efficiency of lactation can be p romoted by facilitating oxytocin release in connection with milking by enha ncing the amount of sensory stimulation. (C) 2001 Elsevier Science B.V. All rights reserved.