Hostname: page-component-78c5997874-t5tsf Total loading time: 0 Render date: 2024-11-08T00:35:06.302Z Has data issue: false hasContentIssue false
  • English
  • Français

The bovine teat canal: information from measurement of velocity of milk flow from the teat

Published online by Cambridge University Press:  01 June 2009

David M. Williams  and
Graeme A. Mein
David M. Williams
Affiliation:
Milking Research Centre, Department of Agriculture and Rural Affairs, Werribee, Victoria, 3030, Australia
Get access Rights & Permissions [Opens in a new window]

Summary

The velocity of milk flow from the teat during the peak flow rate period of milking was estimated to be ∼ 8·5 m/s with a liner vacuum of 50 kPa and 7·5 m/s at 40 kPa. These results confirm the applicability of the Bernoulli theorem for estimating velocity of milk flow through the teat canal during milking. Concurrent measurements of mass flow rate and velocity indicate that the effective diameter of the open teat canal is ∼ 2 mm. Further calculations indicate that the shear force due to milk flow acting to debride the surface of the open teat canal is about 1·8 × 10-2 N. The opposing surfaces of the ‘closed’ teat canal may be ∼ 100 µm apart immediately after milking. If so, bacteria present in the milk residue within the teat canal would never be more than 50 µm from a surface.

Type
Original Articles
Information
Journal of Dairy Research , Volume 53 , Issue 2 , May 1986 , pp. 179 - 185
Copyright
Copyright © Proprietors of Journal of Dairy Research 1986

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Baxter, E. S., Clarke, P. M., Dodd, F. H. & Foot, A. S. 1950 Factors affecting the rate of machine milking. Journal of Dairy Research 17 117–127CrossRefGoogle Scholar
Benedict, R. P. 1980 Fundamentals of Pipe Flow p. 4. New York: John Wiley & SonsGoogle Scholar
Craven, N. 1985 Do rising fat-globules assist microbial invasion via the teat duct between milkings? In Proceedings of the IDF Seminar, Progress in the Control of Bovine Mastitis, 05 21–24, 1985. Kiel, FRGGoogle Scholar
Delwtche, M. J., Scott, N. R. & Drost, C. J. 1980 Ultrasonic measurement of teat milk flow. St. Joseph, MI: American Society of Agricultural Engineers (ASAE Technical Paper No. 86–3029)Google Scholar
Duncan, W. J., Thom, A. S. & Young, A. D. 1974 Mechanics of Fluids. 2nd edn, SI Units. Caulfield East, Victoria, Australia: Edward ArnoldGoogle Scholar
Holland, F. A. 1973 Fluid for Chemical Engineers. SI Units. London: Edward ArnoldGoogle Scholar
Kay, J. M. & Nedderman, R. M. 1974 An Introduction to Fluid Mechanics and Heat Transfer. 3rd edn. Cambridge: Cambridge University PressGoogle Scholar
McDonald, J. S. 1973 Radiographic method for anatomic study of the teat canal: changes within the first lactation. American Journal of Veterinary Research 34 169–171Google ScholarPubMed
Mein, G. A., Thiel, C. C. & Akam, D. N. 1973 Mechanics of the teat and teatcup liner during milking: information from radiographs. Journal of Dairy Research 40 179–189CrossRefGoogle Scholar
Reiter, B. & Bramley, A. J. 1975 Defence mechanisms of the udder and their relevance to mastitis. In Proceedings of Seminar on Mastitis Control 1975 pp. 210–222. International Dairy Federation Bulletin Document 85Google Scholar
Smith, V. R. & Peterson, W. E. 1946 The effect of increasing the negative pressure and widening of the vacuum-release ratio on the rate of removal of milk from the udder. Journal of Dairy Science 29 45–53CrossRefGoogle Scholar
Thompson, P. D. & Campbell, L. E. 1975 Monitoring the flow of milk within machine milked teat by observing Doppler shift of back-scattered ultrasound. Transactions of the ASAE 17 496–499, 504Google Scholar
Williams, D. M. 1984 A study of the epithelium of the bovine teat canal. Ph.D thesis, University of Melbourne, AustraliaGoogle Scholar
Williams, D. M. & Mein, G. A. 1982 Physical and physiological factors affecting milk flowrate from the bovine teat during machine milking. Proceedings of the Conference on Dairy Production from Pasture, Hamilton, New Zealand, pp. 42–74. (Eds Macmillan, K. L. and Taufa, V. K.). New Zealand and Australian Societies of Animal Production (New Zealand Society of Animal Production Occasional Publication no. 8)Google Scholar
Williams, D. M. & Mein, G. A. 1985 The role of the milking machine in the invasion of mastitis organisms and implications for maintaining low infection rates. In Proceedings of the IDF Seminar, Progress in the Control of Bovine Mastitis, 05 21–24, 1985 Kiel, FRGGoogle Scholar
Woolford, M. W., Phillips, D. S. M. & Twomey, A. 1978 A comparison of mastitis infection a rates using a conventional intermittent milk flow and a continuous milk flow under conditions of an elevated standard bacterial challenge. Proceedings, Annual Meeting. National Mastitis Council 17 275–290 (International Symposium on Machine Milking)Google Scholar