Oxytocin release, milk ejection and milk removal in a multi-box automatic milking system

The aim of this study was to test effects of pre-milking udder preparation and of vibration stimulation during teat cup attachment on milk ejection and milk removal in the multi-box AMS "Leonardo". Cows were randomly assigned to four different treatments in a 2 X 2 factorial design and during 3 weeks quarter milk flow was recorded. Tested factors were brushing in a prep-box (yes, no) and vibration stimulation during attachment of teat cup liners (yes, no). During 5 days blood samples were taken from 20 cows during their voluntary milkings. Udder brushing induced oxytocin (OT) release, while in milkings without udder brushing OT levels remained basal until attachment of first teat cup. Between the end of brushing and attachment of first teat cup OT levels decreased transiently. During teat cup attachment already attached teat cups induced OT release, surprisingly also in treatments without any vibration stimulation. OT levels remained elevated throughout milking in all treatments. Despite interruption of tactile udder stimulation between udder cleaning and teat cup attachment milk ejection and milk removal was normal. (C) 2002 Elsevier Science B.V. All rights reserved.