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Research article2004Peer reviewed

Oxytocin, prolactin and somatostatin in lactating sows: associations with mobilisation of body resources and maternal behaviour

Valros A, Rundgren A, Spinka M, Saloniemi H, Hulten F, Uvnas-Moberg K, Tomanek M, Krejci P, Algers B


The aim of the present study was to investigate how oxytocin, prolactin and somatostatin during nursings relate to maternal characteristics of sows. Undisturbed nursing behaviour and sow-piglet nasal contacts of 21 lactating sows were recorded on day 13 of lactation, and hormonal status was assessed during three successful nursings on day 14. Piglet and litter growth (days 8-15), sow weight loss (days 1-15) and catabolic state (measured as NEFA on day 7), as well as number of successful nursings on day 13 were used as measures of mobilisation of sow body resources. Nasal contacts and sow behaviour facilitating udder massage were used as measures of positive piglet-directed behaviours. Concentrations of oxytocin were higher, those of prolactin lower and those of somatostatin similar during nursings compared to samples taken 15 min after nursing. Oxytocin peaked during most nursings and prolactin increased gradually after nursings. Non-nursing oxytocin values were positively correlated with the proportion of sow-terminated nursings but not with other measures of piglet-directed behaviour. Non-nursing oxytocin concentrations were positively correlated with piglet weight gain and concentrations of oxytocin during nursings were correlated with NEFA and sow weight loss. Our results indicate that oxytocin might have more than merely an all-or-nothing function in triggering milk ejection. Oxytocin seems to be quantitatively related to efficiency of milk production, although the present study design does not allow for speculation on causal relationships. (C) 2003 Elsevier B.V. All rights reserved

Published in

Livestock Production Science
2004, Volume: 85, number: 1, pages: 3-13