Milk removal in the calf presence early postpartum and release of oxytocin and prolactin
2002
Tancin, V. | Mihina, S. | Hetenyi, L. (Vyskumny Ustav Zivocisnej Vyroby, Nitra (Slovak Republic)) | Schams, D. | Tancinova, D. | Kraetzl, W.D.
The aim of the study was to compare the milk yield of twenty-four primiparous (primi) and six multiparous dairy cows milked in or without the calf presence after parturition. The release of oxytocin (OT) and prolactin (PRL) was examined in suckled primi cows in response to suckling (S) and milking (M) in the calf presence. The cows were calved in calving box and then relocated to nearby box and tied. Cows were milked twice daily at 07.00 and 17.30 h using a bucked milker. From seventeen primi cows the calf was removed after parturition (non-suckled). The S stimulus in seven primi and six multiparous cows was performed three times daily at 09.00, 14.00 and 20.00 h for a maximum of 15 min each time (suckled). On fifth day after parturition the blood samples were collected during both M and S in suckled primi cows only. The inhibition of milk removal during first M after parturition was found in six primi and only in one multiparous cow in suckled group. Only in six from seventeen non-suckled primi cows the inhibition of milk removal was found. The release of OT during M was significantly reduced as compared with S (25.36+-21.23 v.s. 43.26+-21.45, P0.05). On the other hand, the release of PRL was higher during M as found during S (83.86+-46.87 v.s. 57.32+-32.29, P0.05). The calf presence strengthens the milk removal disturbances in primi cows as a consequence of activation of central mechanisms involved in the oxytocin release. The lower OT and higher PRL released during milking in the calf presence indicate that the OT release in response to suckling seems to be regulated not only by the tactile stimulation of the teats but mechanisms at the central level are involved too
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