Interactions of vacuum, b-phase duration, and liner compression on milk flow rates in dairy cows

Vacuum, b-phase duration, and liner compression are 3 milking machine factors that affect peak milk flow rate; however, extreme values of these factors can also have negative effects on teat tissue health. The main and interactive effects of vacuum, b-phase duration, and liner compression on peak mi...

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Bibliographic Details
Published in:Journal of dairy science 2009-03, Vol.92 (3), p.913-921
Main Authors: Bade, R.D., Reinemann, D.J., Zucali, M., Ruegg, P.L., Thompson, P.D.
Format: Article
Language:English
Subjects:
Animal productions
Animals
b-phase duration
b-phase duration compression
Biological and medical sciences
Cattle - physiology
compressors
dairy cows
Dairying - methods
Female
flow
Food industries
Fundamental and applied biological sciences. Psychology
Lactation
liner compression
Mammary Glands, Animal - physiology
Milk - metabolism
Milk and cheese industries. Ice creams
milk pumps
milking rate
pulsation
Random Allocation
Terrestrial animal productions
Time Factors
Vacuum
vacuum compression
vacuum pumps
Vertebrates
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Summary:Vacuum, b-phase duration, and liner compression are 3 milking machine factors that affect peak milk flow rate; however, extreme values of these factors can also have negative effects on teat tissue health. The main and interactive effects of vacuum, b-phase duration, and liner compression on peak milk flow rate were studied by independently controlling these causal variables over a wide range of settings, using a central composite experimental design (42 to 53 kPa of system vacuum, 220 to 800ms of b-phase, and residual vacuum for massage of 16 to 30 kPa; corresponding to a liner compression of 8 to 14 kPa). The results of this study indicated that increasing the vacuum and b-phase duration always increased peak milk flow rate (no relative maximum was reached); however, the rate of increase of flow rate decreased as the vacuum and b-phase were increased. Increasing the liner compression also increased peak flow rates, with an increasing effect at greater vacuum. The interaction between vacuum and liner compression and the lack of interaction between b-phase and liner compression indicate that for a corresponding increase in peak milk flow rate, increasing the b-phase produced less teat-end tissue congestion than increasing the vacuum. The effect of milking vacuum on peak milk flow rate was smaller than that reported in previous studies, probably because of the independent adjustment of milking vacuum and liner compression used in this study. The effect of b-phase duration on peak milk flow was also smaller in this study than in previous studies, probably because of the independent adjustment of b-phase and d-phase durations used in this study.
ISSN:0022-0302
1525-3198
DOI:10.3168/jds.2008-1180