1 The production of high quality milk depends upon
goats, properly fed and cared for, and milked in a
2 Dairy goats may be milked equally well by hand or by
either case, care must be taken to produce a clean,
and to prevent injury and/or infection of the udder.
The milking unit removes milk from the teat of the
animal by the
application of a partial vacuum. Vacuum is measured in
inches of mercury.
The recommended range of vacuum level on the milking
system is between
10.0 and 14.0 inches of mercury. The primary effect of
vacuum levels is milking rate. As vacuum level
increases, milking rate
increases. Within these vacuum level ranges, no
difference in udder
infection rates will be noted.
4 The Milking Unit
The operation of the milking unit is shown in Figure
1. The pulsator
causes the machine to switch from the milking phase to
the rest phase. As
the pulsator operates, it causes the chamber between
the shell and the
inflation to alternate regularly from vacuum to air
5 During the milking phase, the space between the
inflation and shell
becomes a vacuum. Equal pressure inside and outside of
causes it to open and the milk to flow.
6 During the rest phase, air at normal pressure enters
shell and inflation. Due to the vacuum in the stem the
collapses around the teat. The pressure of the
collapsed inflation on the
teat prevents congestion of blood and body fluids in
the teat skin and
7 The rate at which the inflation is closed and
opened, called the
pulsation rate, varies from 40 to 80 pulsations per
minute depending upon
the manufacturer. The optimum pulsation rate is yet to
be determined. The
manufacturer's recommendations for a particular
pulsator should be
8 Pulsator Ratio
The pulsator ratio is the length of time the pulsator
is in milking
position compared to the time it is in rest position.
It is expressed as
a simple ratio or as percentage of time open to time
closed. The ratio
should range between 50:50 and 60:40 milk to rest
9 Inflations or Teat-cup Liners
Many types of teat-cup shell and inflation
available. Teat size governs the choice of inflation
size. In general,
large teated animals can utilize larger inflations
while the smaller teats are best milked with smaller
10 Claw units should be equipped to admit a small
amount of air in
order to prevent milk from building up in the claw and
block''. An air bleed is necessary on most types of
11 The Vacuum Pump
The most important consideration with regard to the
vacuum pump is
that it possess ADEQUATE CFM CAPACITY AT THE
OPERATIONAL VACUUM LEVEL.
Manufacturers can provide CFM ratings for various
vacuum pumps or the CFM
delivery can be determined by the use of a flow rate
12 The size of pump needed for milking machine
operation depends upon a
number of factors. Among these are:
1. Number of units
2. Size and length of pulsating lines
3. Type of pulsator
4. Type of system (bucket or pipeline)
5. Requirements of other vacuum-operated
13 The recommended capacity of the vacuum pump(s) used
in bucket milking
systems is shown in Table 1. Table 2 indicates
suggested capacities for
14 ++++MISSING DATA++++
15 Make sure that your system has adequte CFM
capacity. Check with your
manufacturer for the vacuum pump ratings.
16 The vacuum pump and the power unit should be
installed as close as
possible and practical to the center of the milking
area. Such locations
as a feed room or near a haymow chute should be
avoided. The exhaust
from the pump should be piped to the outside of the
building through a
pipe whose diameter is at least as great as that of
the pump's discharge
17 Since oil is present in most exhausts, the exhaust
should be directed
downward and away from the side of the building, which
water from entering the pump, and also prevents
accumulation of oil and
dirt on the side of the building.
18 Servicing the pump should be performed as directed
in the service
manual. Maintaining the oil level in the sump or
supply cup and checking
the belt for proper alignment and tension are the two
maintenance procedures, and should be done every two
annual or semi-annual service checks will vary with
the pump and the
19 Vacuum regulators admit air into the milking system to
vacuum level from going too ++++MISSING DATA++++
20 Regulator performance is affected by basic design.
regulators are the most effective, while weighted
level types are the
21 Pipe Sizes
The milking units are operated by a piping system(s)
which must be
large enough to permit the units to function properly.
and milk line sizes may result in ma ++++MISSING
22 Install low lines where possible. The hoses to the
should not exceed six (6) feet in length. Adequate
pipeline slope and
size are essential to prevent flooding of the system.
erratic vacuum changes in the system, which may result
udder irritation and a possible increase in the
incidence of new
23 The size of sanitary milk pipe is shown in Table 3. Sanitary Milk Pipe Size (inches)
Pipe Size Maximum Number of Units per Slope 1 1/2 4 2 8 These sizes apply to conditions where the animal is
into the milk pipeline. Pipes for weigh jar systems
as milk transfer and wash lines must be of adequate
size for washing.
24 Number of Units
The number of units you should have varies widely,
depending upon the
type of system, the nature of the goats (fast or slow
milking), and the
operator. The following table may serve as a guide for
the number of
units to use.
Table 4. Maximum Number of Milking Units per Operator
Type of System Maximum Number of Units
Milking area only 2
Elevated single stall 2
Elevated platform 3
Herringbone parlor 6
(units both sides of parlor)
25 Milking Practices
Good milking practices are essential to keep goats
healthy and to
achieve good labor efficiency.
26 During milking, there are two critical periods when udder damage is
most likely to occur: at the beginning and the end.
27 Make sure the animal is properly stimulated for
to attaching the machine. The stimulation should be
accomplished in the
same manner at each milking. The interval between
stimulation and machine
application should be short and constant. Ideally, the
machine-on time should be about one minute. The
effect lasts about 7 minutes. It is important that the
goat be milked
out rapidly and the machine removed as soon as the
goat is milked out.
Washing the udder to remove dirt and at the same time
goat for ''let-down'' is u ++++MISSING DATA++++
29 Checks and Maintenance
A regular thorough checking and maintenance schedule
is essential to
keep equipment in top working condition. The
manufacturer of your
equipment has specified many items. Follow those
30 Several items apply to all systems. The most
important are as
1. Check vaccuum level.
2. Make sure pulsators are operating properly.
3. Check rubber parts for breaks, tears, and
4. Check vacuum pump oil supply and belt tension.
5. Install clean filters.
6. Make sure air inlets to claw assemblies are open.
1. Check and clean vacuum regulator.
2. Inspect and rotate inflations.
3. Check couplings and stall cocks for leaks and
1. Disassemble pulsator and check for wear. Clean all
2. Check condition of vacuum pump oil.
3. Check CIP (clean-in-place) system for proper
cycling and water
4. Check pulsator performance with portable test
1. Check operation of the vacuum pump. Use a flow rate
determine if it is pumping at its rated capacity.
2. Connect the system and obtain an air flow reading
with the system
in operation. A loss of more than 10 percent of the
capacity indicates excessive leaks in the system.
3. Check all pipeline gaskets for leaks and condition.
4. Check electrical connections and the pulsation
control. A voltage
meter is suggested to check the electrical pulsation
5. Make all service checks as specified by the