PARAMETERS IN MILK QUALITY AND MASTITIS
3 The milking routine and its effect on milk quality
Sanitizing, presquirting and drying prime the cow for milking. These procedures stimulate the cow for milking and cause the release of the let-down hormone oxytocin. If milk let-down does not occur, milking will be incomplete and slow. Oxytocin is short-lived in the bloodstream and milking machines should be attached before oxytocin clears from the blood. Thus milking machines should be attached to the teats approximately one minute after the initiation of the premilking routine with as little air admission as possible. Milkers should be adequately trained so that 95 % of the teat cups are attached without audible air leaks. Milking should be done as quickly and rapidly as possible, and air and milk movement through the short milk tube should not be obstructed. Individual quarter teat cups should not be dropped near the end of milking. This, too, can impact milk quality and increase the chances of new intramam-
Figure 4. Teats should be dried completely with a single towel.
mary infections. Rushing to attach the milk unit might reduce the length of the premilking routine but will ultimately lead to a slower milk flow and thus a significant increase in milking time.
It is also very important to maintain regular and consistent milking intervals, as milk needs to be regularly removed to maximize milk synthesis and yield.
POSTMILKING PROCEDURES REMOVAL OF THE MILKING UNIT Machine stripping of the cows should be avoided. The two most critical times for udder damage to occur during milking are at the beginning, due to poor stimulation, and at the end, from
An accumulation of milk in the mammary gland will increase
overmilking, excessive stripping and improper removal. Over-
intramammary pressure (Sjaastad et al., 2010). This leads
milking can be prevented by the use of automatic detachers. In
to a decrease in mammary blood flow, which decreases the
the absence of automatic detachers, milkers need to be trained
uptake of milk precursors resulting in a decrease in milk syn-
and attention has to be paid to milk flows to avoid overmilking.
thesis (Delmaire and Guinard-Flament, 2006). A decrease in mammary blood flow could also lead to an increase in the microbial colonization of the mammary gland as milk removal
POSTMILKING DISINFECTION
has a washout effect (Sandholm and Korhonen, 1995). These
After the milking unit has been removed, the teats need to
practices are not always followed at each milking, as proce-
be disinfected with a recommended, effective and approved
dural drifts tend to happen. When observing milking proce-
teat dip covering 75 to 90 % of the entire teat. The teats are
dures it is important to check that they are being properly
bathed with milk during the milking process and the teat dis-
executed.
infectant will remove the milk film from the teat after the milking
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