FLORIDA AGRICULTURAL EXPERIMENT STATIONS
Dairy Science Mimeo Report DY65-4
June 18, 1965
MILKING EQUIPMENT DESERVES CAREFUL MANAGEMENT
J. M. Wing and J. P. Boggsl.
Milking machines and allied equipment are the only implements used twice
every single day. They work more hours than any other machine, and
more labor is used in milking than in any other farm operation. Yet the
milking machine usually is the least understood and most often neglected
piece of equipment on most farms.
All milking machines operate by vacuum. This applies to those employing
either pails or pipelines. The vacuum on the teats is continuous; it is
strong, too, and would cause severe damage but for the massaging action
of the inflations (teat cup liners). They work in the following manner.
Continuous vacuum on the inside of the inflation causes it to collapse.
Periodically the pulsator applies vacuum between the inflation and the
teat cup. It is during this interval that most of the milk flows since
the inflation snaps back to its normal shape. The alternate collapse
and recovery of the liner massages the teats, achieving the same stimula-
tion to blood and lymph circulation as nursing by a calf or the pressure
exerted by a good hand-milker.
The manufacturers of milking systems supply easily understood instructions
for the care, repair and operation of their products. These should be
followed closely, but additional information also is likely to be helpful.
The following check list usually can be used to locate trouble without a
long interruption. It applies to both pipeline and pail-type milkers.
A. If the machines have to be left on the cows for an average of more
than 3-1/2 minutes, it is likely that there is a malfunction.
1. The inflation may be broken. This defect usually announces
itself with a persistent hissing noise.
2. One or more of the inflations may be worn or stretched. This
likewise can cause a hissing noise and may irritate the teats.
Useful life of rubber teat cup liners can be extended many times
by keeping two sets and alternating them at weekly intervals.
Inflations not in use may be reconditioned in two different ways./
a. They may be stored dry in a refrigerator. The cold appears /
to restore elasticity to the rubber, shortening the inflation
b. They may be stored in a concentrated solution of lye. This
will do more to restore the condition of the rubber than will
dry storage. One must have soft water for this type of
.The authors are Associate Dairy Husbandman and Dairy Research Unit
operation, otherwise the lye is likely to cause a mineral scum
which is very difficult to remove. Plastic-lined metal pails
or plastic containers can be used as storage units but the
lye must not be mixed in these vessels because the heat of
solution often is enough to melt plastic.
3. The vacuum supply may be inadequate.
a. If the slow milking occurs mainly at the greatest distance
from the vacuum pump, the lines may be too small. It appears
that lines in many older barns should be replaced with larger
ones and/or additional vacuum controllers may be needed.
b. The vacuum pump may be too small for the operation, particularly
if the number of machines has been increased since the original
c. The belt between the motor and the vacuum pump could be slipping
due to wear or improper adjustment.
d. The oil in the vacuum pump may be too low.
e. The vacuum line possibly has a leak.
f. Air hoses or operating covers may be leaky.
g. Vacuum lines or hoses could be plugged. They should be cleaned
thoroughly at least once each week, even though nothing but
air supposedly goes through them. On machines having adjust-
able pulsators, it is possible that the pulsation is too fast.
For the other type machines, the pulsation rate is likely to
be correct as long as unusual electrical malfunctions have not
B. At times the machine milks faster at some of the teat cups than at
others. This may be caused by:
1. Leaking or stretched inflations
2. The teat cups may be improperly attached
3. The air hose may be leaking
4. The pulsator may be worn
5. The animal may have malformed or injured teats.
C. If undue irritation to the udder or frequent mastitis occurs, the
following should be checked:
1. The machine may be left on too long. Any time the teat cups
creep upward they are likely to rub tender tissues of the udder
together causing injured teats and possibly more serious
2. Machine may have been removed without breaking the vacuum. To
release the vacuum the udder should be pushed in just above the
teat cup, allowing air to enter the system.
3. The pulsator may be too slow.
4. The pulsator may have stopped due to failure of the mercury
switches on equipment employing this type of control.
5. The pulsators may have been damaged or worn.
6. The pulsators may be blocked by dirt or other foreign matter.
7. The vacuum may be too high.
8. The vacuum regulator may be stuck or improperly adjusted. It
should be inspected and cleaned at regular intervals.
9. The entire system should be checked periodically, twice a year
if possible, by a factory-trained representative with special
10. The pump speed may be too fast due to improper pulleys or a
malfunction in the electrical service.
D. Excessive bacterial counts. Special attention after each milking
must be given to spots which brushes are likely to miss. Square corners
are disappearing from modern dairy equipment but to the extent that they
still exist, these spots must be inspected with special care since they
are particularly difficult to clean. Another frequently missed hiding
place for bacteria is just under the flange of the inflations.
Milking machine operators are food handlers. They must be sanitation-
conscious and keep in mind the following points:
1. All equipment must be washed as soon after use as possible.
2. Use a cold water rinse first to remove material which would be
cooked onto the surface by hot water, thus starting a milkstone
3. Then wash with hot water, a good detergent, and scrub thoroughly
with a good brush.
4. Sanitize washed utensils with an approved bacterial inhibitor.
Most of the usual dairy sanitizing materials can be used to wash
the udders, and to rinse the teat cups between cows. Dip and wash
solutions must be changed often, however, or they do more harm
than good. Quarternary ammonium compounds and tamed iodine solutions
are increasing in popularity for use during milking. This is partly
because chlorine is likely to be irritating to the udders and the
milkers' hands, and to be harmful to the wash cloths. Another point
is that the effect of chlorine solutions is inhibited by the presence
of organic matter. Chlorine continues to be a favorite for use on
No job on the dairy is more important than milking and nothing gives more
satisfaction than properly harvesting and handling Nature's most nearly
perfect food. Alertness and a systematic inspection can save many
service calls and promote herd health.