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Simultaneous recording of oxytocin release, milk ejection and milk flow during milking of dairy cows with and without prestimulation

Published online by Cambridge University Press:  01 June 2009

Rupert M. Bruckmaier
Affiliation:
Institut für Tierzucht der Universität Bern, CH-3012 Bern, Schweiz
Jürg W. Blum
Affiliation:
Institut für Tierzucht der Universität Bern, CH-3012 Bern, Schweiz

Summary

The effects of manual teat stimulation compared with stimulation by the liner of a conventional milking machine and the influence of milk ejection on the course of milk flow during the entire milking were investigated. Twelve cows were milked with or without prestimulation on three quarters and milk flow was recorded while intramammary pressure (IMP) was recorded in the left front quarter and blood samples for the determination of oxytocin (OT) were taken at 1 min intervals. OT concentrations increased very similarly in response to manual teat stimulation or liner stimulation and remained elevated during the entire milking procedure. Milk flow curves were generally bimodal without stimulation and not bimodal during milking after prestimulation. Milk yield was not significantly lower in milkings without than with stimulation, whereas machine-on time was prolonged and peak milk flow rate was reduced during milking without stimulation. Time to reach milk flow plateau, time to reach peak flow rate and IMP profiles were similar in both treatments if time was calculated from the start of stimulation. IMP increased similarly in response to manual or liner teat stimulation. In milkings with and without prestimulation IMP did not reach its maximum until the start of milking. In bimodal milk flow curves the second increase of milk flow occurred concomitantly with the start of IMP increase; ejection IMP generally occurred concomitantly with the milk flow plateau. In some cases during milking without prestimulation only small and transient OT release was observed. In response, IMP did not increase to its maximum and increased further in response to a stripping-related OT release. During the course of milking IMP decreased slightly because of the emptying of the three milked quarters. After the end of milking, and with OT concentrations decreasing to the premilking values, IMP again decreased slightly to another plateau, probably owing to myoepithelial relaxation. Thus the course of milk ejection, i.e. the IMP profile, influenced milk removal markedly during early milking.

Type
Original Articles
Copyright
Copyright © Proprietors of Journal of Dairy Research 1996

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References

REFERENCES

Bruckmaier, R. M., Pfeilsticker, H. -U. & Blum, J. W. 1996 Milk yield, oxytocin and β-endorphin gradually normalize during repeated milking in unfamiliar surroundings. Journal of Dairy Research 63 191200CrossRefGoogle ScholarPubMed
Bruckmaier, R. M., Rothenanger, E. & Blum, J. W. 1994 a Measurement of mammary gland cistern size and determination of the cisternal milk fraction in dairy cows. Milchwissenschaft 49 543546Google Scholar
Bruckmaier, R. M., Rothenanger, E. & Blum, J. W. 1995 Milking characteristics in dairy cows of different breeds from different farms and during the course of lactation. Zeitschrift für Tierzuchtung und Zuchtungsbiologie 112 293302Google Scholar
Bruckmaier, R. M., Schams, D. & Blum, J. W. 1994 b Continuously elevated concentrations of oxytocin during milking are necessary for complete milk removal in dairy cows. Journal of Dairy Research 61 323334CrossRefGoogle ScholarPubMed
Gorewit, R. C. & Gassman, K. B. 1985 Effects of duration of udder stimulation on milking dynamics and oxytocin release. Journal of Dairy Science 68 18131818CrossRefGoogle ScholarPubMed
Knight, C. H., Hirst, D. & Dewhurst, R. J. 1994 Milk accumulation and distribution in the bovine udder during the interval between milkings. Journal of Dairy Research 61 167177CrossRefGoogle ScholarPubMed
Mayer, H., Bruckmaier, R. M. & Schams, D. 1991 Lactational changes in oxytocin release, intramammary pressure and milking characteristics in dairy cows. Journal of Dairy Research 58 159169CrossRefGoogle ScholarPubMed
Mayer, H., Schams, D., Worstorff, H. & Prokopp, A. 1984 Secretion of oxytocin and milk removal as affected by milking cows with and without manual stimulation. Journal of Endocrinology 103 355361CrossRefGoogle ScholarPubMed
Mayer, H., Worstorff, H., Schams, D. & Klein, M. 1985 Secretion of oxytocin and milking characteristics in cows as affected by several modes of tactile teat stimulation. Milchwissenschaft 40 15Google Scholar
Pfeilsticker, H. -U., Bruckmaier, R. M. & Blum, J. W. 1995 Interruption of machine milking in dairy cows: effects on intramammary pressure and milking characteristics. Journal of Dairy Research 62 559566CrossRefGoogle ScholarPubMed
Sagi, R., Gorewit, R. C., Merrill, W. G. & Wilson, D. B. 1980 Premilking stimulation effects on milking performance and oxytocin and prolactin release in cows. Journal of Dairy Science 63 800806CrossRefGoogle ScholarPubMed
SAS 1993 SAS User's Guide: Statistics. Cary, NC: SAS InstituteGoogle Scholar
Schams, D., Mayer, H., Prokopp, A. & Worstorff, H. 1984 Oxytocin secretion during milking in dairy cows with regard to the variation and importance of a threshold level for milk removal. Journal of Endocrinology 102 337343CrossRefGoogle Scholar