• TABLE OF CONTENTS
HIDE
 Front Cover
 Table of Contents
 Introduction
 Anatomy of the udder
 Histology of the mammary gland
 Teat histology
 The lymphatic system
 The circulatory system
 The milk leftdown process
 The milk removal process
 Mastitis
 Mastitis control practices
 Milking machine factors
 Components of the milking...
 Parlor automation and optional...
 Keeping the system clean
 Milking equipment cleaning
 Stray voltage and mastitis
 Sizing the milking system
 Trouble shooting a problem...
 Back Cover






Group Title: Circular - Florida Cooperative Extension Service - 1136
Title: Milking machine and mastitis control handbook
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00008560/00001
 Material Information
Title: Milking machine and mastitis control handbook
Series Title: Circular
Physical Description: 22 p. : ill. ; 28 cm.
Language: English
Creator: Bray, D. R ( David Russell ), 1940-
Shearer, Jan K
Florida Cooperative Extension Service
Publisher: University of Florida, Institute of Food and Agricultural Sciences, Florida Cooperative Extension Service
Place of Publication: Gainesville
Publication Date: [1994]
 Subjects
Subject: Mastitis -- Florida   ( lcsh )
Milking machines   ( lcsh )
Dairy cattle -- Diseases   ( lcsh )
Udder -- Diseases   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: D.R. Bray and J.K. Shearer.
General Note: Cover title.
General Note: "Printed April 1994"--Colophon.
Funding: Circular (Florida Cooperative Extension Service) ;
 Record Information
Bibliographic ID: UF00008560
Volume ID: VID00001
Source Institution: Marston Science Library, George A. Smathers Libraries, University of Florida
Holding Location: Florida Agricultural Experiment Station, Florida Cooperative Extension Service, Florida Department of Agriculture and Consumer Services, and the Engineering and Industrial Experiment Station; Institute for Food and Agricultural Services (IFAS), University of Florida
Rights Management: All rights reserved, Board of Trustees of the University of Florida
Resource Identifier: aleph - 001927321
oclc - 30847573
notis - AKA3304
 Related Items
Other version: Alternate version (PALMM)
PALMM Version

Table of Contents
    Front Cover
        Front Cover
    Table of Contents
        Table of Contents
    Introduction
        Page 1
    Anatomy of the udder
        Page 1
    Histology of the mammary gland
        Page 2
    Teat histology
        Page 2
    The lymphatic system
        Page 3
    The circulatory system
        Page 3
    The milk leftdown process
        Page 3
    The milk removal process
        Page 4
    Mastitis
        Page 5
    Mastitis control practices
        Page 6
        Page 7
    Milking machine factors
        Page 8
    Components of the milking system
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
    Parlor automation and optional equipment
        Page 15
        Page 16
    Keeping the system clean
        Page 17
    Milking equipment cleaning
        Page 17
    Stray voltage and mastitis
        Page 18
    Sizing the milking system
        Page 19
    Trouble shooting a problem herd
        Page 20
        Page 21
        Page 22
    Back Cover
        Back Cover
Full Text









Milking Machine and

Mastitis Control Handbook


D.R. Bray and J.K. Shearer





















University of Florida
Institute of Food and Agricultural Sciences
Florida Cooperative Extension Service
John T. Woeste, Dean


Lv y I -.. .


(Il


Circular 1136














Table of Contents


Page

Introduction 1

Anatomy of the Udder 1

Histology of the Mammary Gland 2

Teat Histology 2

The Lymphatic System 3

The Circulatory System 3

Milk Letdown Process 3

Mastitis 5

Mastitis Control Practices 6

Milking Machine Factors 8

Components of the Milking System 8

Parlor Automation and Optional Equipment 15

Keeping the System Clean 17

Milking Equipment Cleaning 17

Stray Voltage and Mastitis 18

Sizing the Milking System 19

Trouble Shooting a Problem Herd 20









Milking Machine and Mastitis Control Handbook

D.R. Bray and J.K. Shearer1


INTRODUCTION

Mastitis is the most costly disease in the dairy
industry, with the biggest loss from subclinical
mastitis, when bacteria are already in the udder.
These organisms destroy milk-secreting tissue and
thus lower milk production.

Subclinical mastitis cannot be detected on a strip
plate, but it is found through a high somatic cell
count. A count of 1 million cells/ml indicates that
over 30% of a herd's quarters are infected with
mastitis.

Herds with high cell counts and many infected
quarters will have losses in milk production and
income in the range of 20-30%. A 500-cow dairy,
averaging 50 pounds of milk per cow per day for 365
days a year, with a $16 per hundred pounds milk price
that has a 20% loss would lose $292,000 a year
because of mastitis (see Table 1).

Table 1. Estimated potential dollar losses caused by mastitis
on a 500 cow dairy with high cell count.

Loss
% $

Subclinical mastitis milk loss 73 213,160.
Clinical mastitis losses, drug 22 62,240.
cost, dumped milk and labor
Culling 5 14,600.
Total potential mastitis losses 292,000.



ANATOMY OF THE UDDER

The cow's udder consists of four separate quarters
containing a complex network of various sized ducts,
blood vessels and capillaries, ligaments, and secretary
tissue. Because milk is constantly being produced and
is stored in the udder between milkings, it must be
strong and well attached to the cow. In high


producing cows, 60 pounds of milk may be stored in
the udder between milkings.

Udder Support System

The size and shape of the udder may vary
considerably with the age and inheritance of the cow.
Attachment of the udder to the cow is by elastic and
nonelastic suspensory ligaments (see Figure 1). The


Figure 1. Udder support system

median suspensory ligament is located in the center of
the udder and holds the udder up in the middle. The
other inelastic set of ligaments on the outer walls of
the udder are called the lateral suspensory ligaments
and also aid in udder support.

Udder Divisions

The udder is divided into halves by the central
supporting ligament and each half into quarters by a
fine membrane (see Figure 2). While each quarter is
separate and no transfer of milk occurs between
quarters, antibiotics can be transferred from one
quarter to others through the extensive blood network
throughout the udder. This is the reason that a cow
treated in one quarter with antibiotic must have milk
from all quarters discarded, andantibiotics
administered in the muscle or other areas of the body
will end up in the milk through the blood supply
system.


1. Extension Agent III, Milking Management and Mastitis Specialist, Dairy Science Department; Associate Professor, College of Veterinary
Medicine, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville FL 32611.


SMedian
Suspensory
Ligament









Milking Machine and Mastitis Control Handbook

D.R. Bray and J.K. Shearer1


INTRODUCTION

Mastitis is the most costly disease in the dairy
industry, with the biggest loss from subclinical
mastitis, when bacteria are already in the udder.
These organisms destroy milk-secreting tissue and
thus lower milk production.

Subclinical mastitis cannot be detected on a strip
plate, but it is found through a high somatic cell
count. A count of 1 million cells/ml indicates that
over 30% of a herd's quarters are infected with
mastitis.

Herds with high cell counts and many infected
quarters will have losses in milk production and
income in the range of 20-30%. A 500-cow dairy,
averaging 50 pounds of milk per cow per day for 365
days a year, with a $16 per hundred pounds milk price
that has a 20% loss would lose $292,000 a year
because of mastitis (see Table 1).

Table 1. Estimated potential dollar losses caused by mastitis
on a 500 cow dairy with high cell count.

Loss
% $

Subclinical mastitis milk loss 73 213,160.
Clinical mastitis losses, drug 22 62,240.
cost, dumped milk and labor
Culling 5 14,600.
Total potential mastitis losses 292,000.



ANATOMY OF THE UDDER

The cow's udder consists of four separate quarters
containing a complex network of various sized ducts,
blood vessels and capillaries, ligaments, and secretary
tissue. Because milk is constantly being produced and
is stored in the udder between milkings, it must be
strong and well attached to the cow. In high


producing cows, 60 pounds of milk may be stored in
the udder between milkings.

Udder Support System

The size and shape of the udder may vary
considerably with the age and inheritance of the cow.
Attachment of the udder to the cow is by elastic and
nonelastic suspensory ligaments (see Figure 1). The


Figure 1. Udder support system

median suspensory ligament is located in the center of
the udder and holds the udder up in the middle. The
other inelastic set of ligaments on the outer walls of
the udder are called the lateral suspensory ligaments
and also aid in udder support.

Udder Divisions

The udder is divided into halves by the central
supporting ligament and each half into quarters by a
fine membrane (see Figure 2). While each quarter is
separate and no transfer of milk occurs between
quarters, antibiotics can be transferred from one
quarter to others through the extensive blood network
throughout the udder. This is the reason that a cow
treated in one quarter with antibiotic must have milk
from all quarters discarded, andantibiotics
administered in the muscle or other areas of the body
will end up in the milk through the blood supply
system.


1. Extension Agent III, Milking Management and Mastitis Specialist, Dairy Science Department; Associate Professor, College of Veterinary
Medicine, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville FL 32611.


SMedian
Suspensory
Ligament







Milking Machine and Mastitis Control Handbook


duct which empties into a series of mammary (milk)
ducts that get progressively larger until eventually the
milk reaches the gland and teat cisterns.
\ Myoepithelial cells also are found on smaller ducts in
FINE the mammary gland and aid in milk removal.
MEMBRANE

.-. :Lobules and Lobes

Groups of alveoli form lobules that are drained by
a common duct. One lobule may contain 150-250
-OUTER WALL alveoli. Lobules join together to form a lobe that is
drained by a larger duct (see Figure 4). As described
previously these also connect to form still larger ducts
which eventually reach the mammary gland cisterns
Figure 2. Udder di s and ultimately the teat cistern and streak canal as
Figure 2. Udder divisions. and.
milk exits the gland.

HISTOLOGY OF THE MAMMARY GLAND
MYOEPIHEUAL
The Alveolus
ALVEOLAR
SECRETARY LUMN
The alveolus is the basic component of secretary ALVEOLus-
tissue. It is composed of epithelial cells that surround rCEI,, -
a cavity, the lumen. Milk constituents (protein, fat,
lactose) are synthesized and secreted by the epithelial sECRETORY LO
cells into the lumen of the alveolus.

The alveolus is surrounded by numerous muscle I it
cells known as myoepithelial cells (see Figure 3). LO-wor
These are activated by oxytocin and cause milk cuND.C,
ejection from the lumen of the alveolus. Milk is ,/
ejected from the alveolus through the capillary milk
TEAT CISTERN


Figure 4. Mammary duct and lobule-alveolar systems.
MYOEPITHELIAL
CELL
CAPILLARY --- TEAT HISTOLOGY

The teat wall (Figure 5) contains an abundance of
elastic connective tissue and two layers of muscle
tissue (an inner layer of longitudinal muscles and an
SLUMEN outer layer of circular muscles). The teat skin is
covered with a normal squamous cell epithelium and
is hairless. The teat or streak canal is lined with
DUCT epithelium and has a particularly thick layer of flat
cornified epithelial cells. This albuminous layer of
cells is frequently referred to as keratin. Keratin is
vitally important in preventing the entrance of mastitis
Figure 3. An alveolus and its component parts. causing organisms into the mammary gland.


Page 2







Milking Machine and Mastitis Control Handbook


duct which empties into a series of mammary (milk)
ducts that get progressively larger until eventually the
milk reaches the gland and teat cisterns.
\ Myoepithelial cells also are found on smaller ducts in
FINE the mammary gland and aid in milk removal.
MEMBRANE

.-. :Lobules and Lobes

Groups of alveoli form lobules that are drained by
a common duct. One lobule may contain 150-250
-OUTER WALL alveoli. Lobules join together to form a lobe that is
drained by a larger duct (see Figure 4). As described
previously these also connect to form still larger ducts
which eventually reach the mammary gland cisterns
Figure 2. Udder di s and ultimately the teat cistern and streak canal as
Figure 2. Udder divisions. and.
milk exits the gland.

HISTOLOGY OF THE MAMMARY GLAND
MYOEPIHEUAL
The Alveolus
ALVEOLAR
SECRETARY LUMN
The alveolus is the basic component of secretary ALVEOLus-
tissue. It is composed of epithelial cells that surround rCEI,, -
a cavity, the lumen. Milk constituents (protein, fat,
lactose) are synthesized and secreted by the epithelial sECRETORY LO
cells into the lumen of the alveolus.

The alveolus is surrounded by numerous muscle I it
cells known as myoepithelial cells (see Figure 3). LO-wor
These are activated by oxytocin and cause milk cuND.C,
ejection from the lumen of the alveolus. Milk is ,/
ejected from the alveolus through the capillary milk
TEAT CISTERN


Figure 4. Mammary duct and lobule-alveolar systems.
MYOEPITHELIAL
CELL
CAPILLARY --- TEAT HISTOLOGY

The teat wall (Figure 5) contains an abundance of
elastic connective tissue and two layers of muscle
tissue (an inner layer of longitudinal muscles and an
SLUMEN outer layer of circular muscles). The teat skin is
covered with a normal squamous cell epithelium and
is hairless. The teat or streak canal is lined with
DUCT epithelium and has a particularly thick layer of flat
cornified epithelial cells. This albuminous layer of
cells is frequently referred to as keratin. Keratin is
vitally important in preventing the entrance of mastitis
Figure 3. An alveolus and its component parts. causing organisms into the mammary gland.


Page 2







Milking Machine and Mastitis Control Handbook


Figure 5. Internal structure of a normal teat.


THE LYMPHATIC SYSTEM

Lymph is a colorless fluid drained from tissue
spaces by thin walled vessels. These vessels have
many one-way valves that allow lymph to move only
in the direction of the lymph node (see Figure 6).


Figure 6. Lymphatic system of the udder.

The supramammary and other lymph nodes in the
cow's body are responsible for disease resistance by
forming lymphocytes, which are a form of white blood
cell involved in protection against diseases.

When a mastitis infection occurs, the lymph nodes
increase their output of lymphocytes into the
lymphatic vessels, which discharge them into the cow's
blood supply. Lymphocytes then travel to the udder
to combat mastitis infection.


Page 3


THE CIRCULATORY SYSTEM

The flow of blood to the udder is very important
for milk production since it requires about 500
volumes of blood to produce one volume of milk. A
cow producing 100 pounds of milk a day will require
as much as 6000 gallons of blood to circulate to the
udder. The extensive circulatory system needed to
transport blood to the udder is depicted in Figure 7.


Figure 7. Blood circulation to and from the udder. 1, heart;
2, abdominal aorta; 3, posterior vena cava; 4, external iliac
artery and vein; 5, external pudic artery and vein; 6, internal
iliac artery and vein; 7, perineal artery and vein; 8, sigmoid
flexure of the external pudic artery and vein; 9, subcutaneous
abdominal vein; 10, subcutaneous abdominal artery; 11,
cranial mammary artery; 12, caudal mammary artery; 13,
internal thoracic artery and vein; 14, anterior vena cava; and
15, diaphragm.

THE MILK LETDOWN PROCESS

To harvest all the milk from the udder, you must
have the cow's cooperation. To achieve this
cooperation, treat the cow properly, not only during
the milking process, but also from the time the cow is
moved to the milking area.

A cow lets down her milk if she is stimulated
properly before milking. Since cows seem to be
creatures of habit, this stimulation process need not
be extensive but should be consistent. Stimulation
can include washing or massaging the udder and
forestripping milk out of each quarter. During
stimulation nerve impulses cause the pituitary gland
to discharge the hormone oxytocin into the blood
system. Oxytocin then circulates in the blood to the
udder and stimulates contraction of the myoepithelial
cells surrounding the milk-filled alveoli. The milk is
then forced into the duct system and into the gland
and teat cisterns.


SUPRAMAMMARY
LYMPH NODES





LYMPH
VESSELS







Milking Machine and Mastitis Control Handbook


Figure 5. Internal structure of a normal teat.


THE LYMPHATIC SYSTEM

Lymph is a colorless fluid drained from tissue
spaces by thin walled vessels. These vessels have
many one-way valves that allow lymph to move only
in the direction of the lymph node (see Figure 6).


Figure 6. Lymphatic system of the udder.

The supramammary and other lymph nodes in the
cow's body are responsible for disease resistance by
forming lymphocytes, which are a form of white blood
cell involved in protection against diseases.

When a mastitis infection occurs, the lymph nodes
increase their output of lymphocytes into the
lymphatic vessels, which discharge them into the cow's
blood supply. Lymphocytes then travel to the udder
to combat mastitis infection.


Page 3


THE CIRCULATORY SYSTEM

The flow of blood to the udder is very important
for milk production since it requires about 500
volumes of blood to produce one volume of milk. A
cow producing 100 pounds of milk a day will require
as much as 6000 gallons of blood to circulate to the
udder. The extensive circulatory system needed to
transport blood to the udder is depicted in Figure 7.


Figure 7. Blood circulation to and from the udder. 1, heart;
2, abdominal aorta; 3, posterior vena cava; 4, external iliac
artery and vein; 5, external pudic artery and vein; 6, internal
iliac artery and vein; 7, perineal artery and vein; 8, sigmoid
flexure of the external pudic artery and vein; 9, subcutaneous
abdominal vein; 10, subcutaneous abdominal artery; 11,
cranial mammary artery; 12, caudal mammary artery; 13,
internal thoracic artery and vein; 14, anterior vena cava; and
15, diaphragm.

THE MILK LETDOWN PROCESS

To harvest all the milk from the udder, you must
have the cow's cooperation. To achieve this
cooperation, treat the cow properly, not only during
the milking process, but also from the time the cow is
moved to the milking area.

A cow lets down her milk if she is stimulated
properly before milking. Since cows seem to be
creatures of habit, this stimulation process need not
be extensive but should be consistent. Stimulation
can include washing or massaging the udder and
forestripping milk out of each quarter. During
stimulation nerve impulses cause the pituitary gland
to discharge the hormone oxytocin into the blood
system. Oxytocin then circulates in the blood to the
udder and stimulates contraction of the myoepithelial
cells surrounding the milk-filled alveoli. The milk is
then forced into the duct system and into the gland
and teat cisterns.


SUPRAMAMMARY
LYMPH NODES





LYMPH
VESSELS







Milking Machine and Mastitis Control Handbook


Figure 5. Internal structure of a normal teat.


THE LYMPHATIC SYSTEM

Lymph is a colorless fluid drained from tissue
spaces by thin walled vessels. These vessels have
many one-way valves that allow lymph to move only
in the direction of the lymph node (see Figure 6).


Figure 6. Lymphatic system of the udder.

The supramammary and other lymph nodes in the
cow's body are responsible for disease resistance by
forming lymphocytes, which are a form of white blood
cell involved in protection against diseases.

When a mastitis infection occurs, the lymph nodes
increase their output of lymphocytes into the
lymphatic vessels, which discharge them into the cow's
blood supply. Lymphocytes then travel to the udder
to combat mastitis infection.


Page 3


THE CIRCULATORY SYSTEM

The flow of blood to the udder is very important
for milk production since it requires about 500
volumes of blood to produce one volume of milk. A
cow producing 100 pounds of milk a day will require
as much as 6000 gallons of blood to circulate to the
udder. The extensive circulatory system needed to
transport blood to the udder is depicted in Figure 7.


Figure 7. Blood circulation to and from the udder. 1, heart;
2, abdominal aorta; 3, posterior vena cava; 4, external iliac
artery and vein; 5, external pudic artery and vein; 6, internal
iliac artery and vein; 7, perineal artery and vein; 8, sigmoid
flexure of the external pudic artery and vein; 9, subcutaneous
abdominal vein; 10, subcutaneous abdominal artery; 11,
cranial mammary artery; 12, caudal mammary artery; 13,
internal thoracic artery and vein; 14, anterior vena cava; and
15, diaphragm.

THE MILK LETDOWN PROCESS

To harvest all the milk from the udder, you must
have the cow's cooperation. To achieve this
cooperation, treat the cow properly, not only during
the milking process, but also from the time the cow is
moved to the milking area.

A cow lets down her milk if she is stimulated
properly before milking. Since cows seem to be
creatures of habit, this stimulation process need not
be extensive but should be consistent. Stimulation
can include washing or massaging the udder and
forestripping milk out of each quarter. During
stimulation nerve impulses cause the pituitary gland
to discharge the hormone oxytocin into the blood
system. Oxytocin then circulates in the blood to the
udder and stimulates contraction of the myoepithelial
cells surrounding the milk-filled alveoli. The milk is
then forced into the duct system and into the gland
and teat cisterns.


SUPRAMAMMARY
LYMPH NODES





LYMPH
VESSELS







Milking Machine and Mastitis Control Handbook

If the cow becomes excited or suffers pain either
before or during the milking process, the cow's
cooperation stops. This excitement or pain causes
release of epinephrine (adrenaline) from the adrenal
gland into the blood stream. This reduces the blood
and oxytocin supply to the udder and inhibits
myoepithelial cell contraction and milk ejection (see
Figure 8). In order to remove as much milk as
possible from the udder, it is very important to treat
the cow in a routine and gentle manner, both before
and during milking.


Figure 8. Milk ejection process.


THE MILK REMOVAL PROCESS

There is a positive pressure inside the cow's
udder of about 0.4 pounds per square inch (psi)
before the cow is stimulated; after stimulation the
pressure increases to about 0.8 psi. The sphincter
muscle at the end of the teat is tight enough to keep
the milk inside, but if the muscle is not strong
enough, milk will leak out even before the cow is
stimulated.

Hand Milking

The outside pressure on the teat is one
atmosphere or 14.6 psi. The act of hand pressure and
internal pressure forces open the sphincter muscle
and the milk is removed.


Page 4


Machine Milking

The milking machine usually applies 12.5 to 15
inches Hg (mercury) of vacuum to the outside of the
teat. This produces a pressure differential of 12.5 to
15 inches Hg negative vacuum pressure on the
outside of the teat compared with the 0.8 psi positive
pressure inside the teat. This pressure differential is
great enough to open the sphincter muscle and the
milk is ejected, even at the end of milking when the
internal pressure diminishes.

Since the vacuum applied forces milk out of the
teat, it also forces blood and body fluids to the end of
the teat. If a constant vacuum is applied to the teat,
damage will occur. The pulsator and the double-
chambered teat cups are designed to prevent this
from happening (see Figure 9).


Figure 9. Vacuum (V) applied to exterior of the teat opens
teat canal so that milk is removed. At rest: periodic air (A)
admission to the space between liner and shell permits
closure of liner for massage.

The role of the pulsator is to alternate
atmosphere air and vacuum between the liner and
shell. As already explained, the vacuum causes a
pressure differential that removes the milk from the
streak canal. When the pulsator admits atmospheric
air between the liner and shell, the liner closes
around and below the teat, which in turn flattens the
streak canal causing the milk flow to end. The stress
is removed from the inner and middle tissues of the
streak canal wall.

The liner also applies a compressive force to the
teat end during its collapsed phase, which relieves the
effects of congestion at the teat end.







Milking Machine and Mastitis Control Handbook

MASTITIS

Mastitis is the costliest disease of the dairy
industry today. Losses are estimated to be as much as
$200 per cow annually. It is obvious that dairymen
must control this disease to achieve maximum profit
from their enterprise.

As explained earlier, epithelial cells synthesize
milk constituents (protein, fat, lactose). Mastitis is a
bacterial infection and destroys these milk-secreting
cells. Scar or connective tissue replaces the milk
secreting tissue which results in a permanent loss of
productive ability.

Mastitis organisms enter the udder through the
teat end and streak canal. The streak canal is held
closed by a circular muscle that holds milk in and
foreign matter out, and is lined with keratin, which
traps and kills organisms that attempt to invade
through the teat end.

Mastitis-Causing Organisms

About 95% of all infections are caused by
Streptococcus agalactiae, Staphylococcus aureus,
Streptococcus dysgalactiae, Streptococcus uberis, and
Escherichia coli. The other 5% are caused by other
organisms.

Contagious Organisms

These are spread by hands, milking units, etc.

S. agalactiae lives in the udder and cannot exist
outside the gland for long periods. It is susceptible to
penicillin and,once eliminated, usually does not return
to the herd unless infected cows are purchased.

S. aureus lives in the udder and on the skin
surfaces of an infected cow. It can be controlled
effectively with good management and is moderately
susceptible to antibiotics when the infection first
involves the gland, older infections usually do not
respond to treatment. Severe cases may cause death.

S. dysgalactiae may live almost anywhere: in the
udder, rumen, and feces and in the barn. They can
be controlled with proper sanitation and are
moderately susceptible to antibiotics.

Mycoplasma is a unique organism. It does not fit
the description of a bacterium or a virus and is
classified as a microbe. Mycoplasmas do not have cell


Page 5


walls, leaving them unaffected by most antibiotics that
interfere with cell-wall formation. Since no effective
treatment is available, the best way to control this
disease is to avoid purchasing cattle from known
positive-tested herds. In addition, if cattle are
routinely purchased, the bulk tank and pot herd milk
should be sampled monthly. Mycoplasmas can be
spread through the use of contaminated bottle mixes,
syringes, and teat tubes in treating mastitis cows.
Other infected cows are major sources of infection
which can be transmitted by the milking machine
components, hands of the operator, use of common
rags and sponges, and directly from the environment.
Teat dipping is essential for proper control.

The spread of contagious organisms are
controlled by teat dipping and are eliminated by dry
cow therapy. Herds with contagious mastitis
problems usually have to get back to dip cups and
cover the whole teat to the base of the udder to
control the spread.

Environmental organisms

These live in the cows' environment and are
always present.

Coliform bacteria are environmental pollution
organisms; they live in feces, polluted water, and
bedding material. Excellent sanitation is needed for
their control. They are not susceptible to antibiotics.

S. uberis live most everywhere; in the rumen,
feces and even in the udder. They can be controlled
by proper sanitation and milking clean, dry udders.

When Do Infections Occur?

The rates of new infections are the highest during
the first two weeks of the dry period and the last two
weeks of the dry period. New infection rates are also
high in early lactation and diminish as the lactation
proceeds.

Infection Dynamics

To understand mastitis infection, you must realize
how its level changes on a herd basis. New infections
can be brought into the herd in four general ways: 1)
new infections during lactation, 2) new infections
during the dry period, 3) infected heifers entering the
herd, and 4) infected cow purchases.







Milking Machine and Mastitis Control Handbook

Infections are eliminated in four general ways: 1)
spontaneous recovery, elimination by the animal's
own defense mechanism, 20% effective; 2) use of
lactation therapy, usually 30-40% effective; 3) dry
period therapy, usually 80-90% effective; and 4)
culling the animals, very effective (100%).

Somatic Cells Described

Somatic means of the body. Thus, a somatic cell
is simply a body cell. Examples are skin cells, muscle
cells, bone cells, or virtually any cell in the body. In
milk, however, the predominant cell types are
epithelial and white blood cells.

Epithelial cells of the alveoli are most numerous
and active during early lactation when milk
production is greatest. Throughout the cow's
lactation these cells slowly age and gradually are
sloughed into the milk. Milk production drops during
late lactation as these cells become fewer and less
productive. While this is a dynamic process, the
number of epithelial cells found in milk is relatively
constant throughout lactation.

The other group of cells consistently found in
milk are the infection-fighting cells of the body, the
white blood cells. They always are present in the
udder. However, in the presence of an inflammation
they increase to tremendous numbers. Since
inflammation generally results from infection, high
somatic cell counts in milk are associated with
mastitis.

MASTITIS CONTROL PRACTICES

Proper Milking Procedures

Proper milking procedures are important for the
prevention of mastitis and for insuring complete milk
removal from the udder.

Mastitis can decrease total milk production by 15
to 20%. To minimize loss and achieve maximum milk
yield, a practical milking management scheme should
be followed.

The term milking management also includes care
for the environment in which cows are housed or
pastured. The dairy cow should have a clean dry
environment. This helps reduce the potential for
mastitis and increases milking efficiency by reducing
time and labor to clean udders before the milking
process.


Page 6


Moving Cows

Movement of cows should be in a quiet gentle
manner. If cows are frightened or hurried, the milk
letdown process may be disturbed. Therefore, rough
handling of dairy cattle should be avoided.

Mastitis Detection

Milking may begin with a check of all quarters for
mastitis. It is acceptable to strip milk onto the floor
in a milking parlor or flat barn. Any cows that show
clinical mastitis should be examined and appropriate
action taken. If fore milking is not done, visual
checking for inflamed quarters is done by milkers and
herd health people.

Udder Preparation

The object of udder preparation is to ensure that
clean dry udders and teats are being milked. The
pasteurized milk ordinance (PMO) also states that a
sanitizer must be applied before milking. This task
may be accomplished by using an approved sanitizer
injected in the floor mounted cow washers or by using
a hose and water with a sanitizer on the parlor.
Single service paper towels or washed and dried cloth
towels may be used.

Predipping

Predipping with teat dip has become popular.
The advantage may just be getting the water out of
the milking barn so wet udders are not being milked.

The procedure for predipping involves washing of
teats with water and a sanitizer. The teats are then
dried with an individual paper towel and dipped or
sprayed with the sanitizer. A 30-second contact with
sanitizer is needed to kill organisms. Then the
sanitizer is wiped dry with a paper towel. The cows
are milked and teats are dipped with the same type of
sanitizer to prevent chemical reactions that could
cause irritation to teats.

Predipping may be beneficial in reducing mastitis,
but the actual dipping, dip contact time, and wiping
with a towel increase the total milking time. If the
dip is not wiped off, excessive chemical residues in
milk may occur. If contact time is not sufficient then
it's a very expensive premilking regime.







Milking Machine and Mastitis Control Handbook

Attachment and Detachment of the Milking Unit

To attach the milking unit to the teats, apply the
cluster allowing a minimum of air admission and
adjust to prevent liner slip. Air entering the unit may
cause the propulsion of mastitis organisms from one
infected teat into a noninfected teat. This also may
happen when one teat cup is removed before the
others.

Machine stripping usually is not needed on Dairy
cows. Machine stripping should not take more than
one minute and no air should be allowed to enter the
teat cups while this is being done. A downward force
applied to the cluster while massaging the udder with
the other hand is all that is needed.

Following milk-out, the machine should be
removed only after the vacuum to the teats is shut off.
This is accomplished most commonly by use of a
vacuum shut off valve or milk hose clamp which
prevents the backjetting of bacteria from one teat to
another.

Backflushing

Backflushers have been developed to sanitize the
liners and claws between milkings. Most units on the
market have four or five cycles. The first cycle is a
water rinse, followed by an iodine or similar sanitizer
rinse, a clear water rinse, and positive air dry cycle.

Research has demonstrated that backflushers do
reduce the number of bacteria on the liners between
cows, but do not reduce the number of bacteria on
teats. Backflushers also may stop the spread of
contagious organisms, but this can also be
accomplished at a much lower cost by teat dipping.
There is no effect on environmental pathogens that
are encountered between milkings.

Backflushers may be effective in stopping the
spread of contagious mastitis; however, there is
limited research to support this view. Because of the
high initial cost, need for daily maintenance, and
limited efficacy, backflushers are not routinely
recommended.

Post-milking Teat Dipping

There is only one way to effectively stop the
spread of mastitis in the dairy herd, and that is by
applying teat dip to every quarter of every cow after
every milking. Teat dips are used to remove milk


Page 7


residue left on the teat and kill organisms on the teat
at the time of dipping. They also leave a residual film
of sanitizer between milkings.

Are teat dips effective against all mastitis
organisms? Yes, teat dips have been shown to
effectively reduce mastitis caused by S. areus and S.
agalactia, the most common types of mastitis found in
Florida.

There seems to be much controversy about the
effectiveness of teat dipping on environmental
pathogens E. coli and S. uberis. Some research has
shown that teat dipping does not control these
organisms. These pathogens are found in the cow's
surroundings; if there is udder-deep mud, the teat dip
will be removed and a new infection may occur.

Types of teat dips

There are many effective teat dips, including
iodine at 0.1%, 0.5%, and 1.0%, and chlorhexidine at
0.5%. Also, although it is not labeled for teat dipping,
hypochlorite at 4.0% with a sodium hydroxide content
less than 0.05% was effective in field trials. There are
many more teat dips on the market that are effective
in preventing new infections. Effective coverage of
the teats is more important than the type of dip being
used.

Dip or spray

If contagious bacteria is present in your herd,
strep. ag., strep. dysgalactiae, staph. areus, or
mycoplasma you must dip the whole teat to the base
of the udder to stop the spread. Wand sprayers are
acceptable for herds that have environmental mastitis,
since teat colonization is not a factor. Hand-held
spray bottles are almost worthless in getting proper
coverage of dip on the cow's teats, so they should not
be used.

Dry Cow Therapy

Dry cow treatment is administered after the last
milking of the cow before the dry period. Care must
be taken to scrub the teat end with cotton and alcohol
before infusion and to use teat dip after infusion.

There are many antibiotics available for dry cow
therapy. High levels of penicillin and dihydro-
streptomycin, the cloxacillins and other products
specifically for dry treatment are effective.







Milking Machine and Mastitis Control Handbook

The idea of dry period therapy has been accepted
because antibiotics can be put into a slow release base
that allows them to stay in the udder longer. They
are not constantly being milked out of the udder as is
the case with lactation therapy. Antibiotics can be
administered in higher quantities because there is no
concern for milk levels and antibiotic residues.

While dry treatment is very effective, it must be
administered properly and the dry cows must have
favorable environmental conditions. Teat ends must
be scrubbed clean with cotton alcohol pads before
injecting the dry treatment. If the teat ends are not
cleaned properly, you may inject into the udder very
high numbers of bacteria, which would overwhelm the
antibiotic just administered. Unsanitary treatment
procedures cause rather than eliminate mastitis.

Management of dry cows also is very important in
mastitis control. If dry cows are exposed to muddy or
dirty conditions, risks of mastitis will increase. This
is especially true at the time of calving; cows are
under much stress during this period and if an udder
is exposed to wet dirty conditions, mastitis will
increase. If you believe that your dry cow therapy
program is ineffective, it may be. because of poor
treatment procedures and/ or improper management
of the cows during the dry period and at calving.

Culling

Culling cows for mastitis is effective in eliminating
mastitis in the herd. Cows that have been treated
many times in a single lactation are prime candidates
for culling, as they may no longer be profitable
because of discarded milk and antibiotic costs. It is
usually more profitable to carry out preventive
mastitis control procedures and cull only old chronic
cows rather than to try and control mastitis by routine
culling.

Summary

Mastitis is a very costly disease, but losses can be
reduced greatly by following an effective control
program, which should include the following items:

1. Handle cows gently to achieve highest
production.

2. Follow proper milking procedures, milk clean,
dry udders, apply milking units properly, and
make adjustments to prevent the admittance of
air into the teat cup liners and prevent liner slip.


Page 8


3. Dip cow's teats after milking to prevent new
infections.

4. Treat all cows going dry with an approved dry
cow drug in commercially prepared tubes to
eliminate existing infections and prevent new
infections during the dry period.

5. Cull chronically infected cows.

MILKING MACHINE FACTORS

Research has demonstrated that "liner slip" is one
area in which the milking machine may increase
mastitis. This is when air is admitted through the top
of the teat cup. Milk and bacteria, if present, may be
propelled into the teat end of an adjacent teat, thus
causing a new bacterial infection. Also, the use of
malfunctioning pulsators can cause teat end damage
and increased the rate of new infection.

The milking machine has little effect on mastitis
if properly operated and functioning according to the
manufacturer's specifications. Clearly though, when
operated improperly, milking machines can have a
role, and malfunctioning equipment can cause mastitis
in several ways. If the pulsator is dirty and does not
function properly, this will cause the massage phase
to be eliminated with the teat end being damaged. A
vacuum controller that is dirty also will not function
properly and again damage the teat end. Damage to
this entry area for organisms increases the risk of
mastitis.

COMPONENTS OF THE MILKING SYSTEM

The Vacuum Pump

The vacuum pump is the heart of the milking
system. Its purpose is to remove air from the system,
thus creating a vacuum. Pump capacity is a measure
of how fast the pump can remove air and is,
therefore, measured in cubic feet of air per minute
(CFM). Pump capacity can be expressed as American
Standard (ASME) or New Zealand Standard (NZ).
One CFM ASME equals 2 CFM NZ. It is similar to
measuring the pumping capacity of an irrigation
system in gallons per minute. Since the rate at which
a pump can remove air depends on the vacuum level,
all pump capacity ratings are standardized by
measuring them at 15 inches of mercury. At that
vacuum level, a pump removes air at a constant rate.







Milking Machine and Mastitis Control Handbook

The idea of dry period therapy has been accepted
because antibiotics can be put into a slow release base
that allows them to stay in the udder longer. They
are not constantly being milked out of the udder as is
the case with lactation therapy. Antibiotics can be
administered in higher quantities because there is no
concern for milk levels and antibiotic residues.

While dry treatment is very effective, it must be
administered properly and the dry cows must have
favorable environmental conditions. Teat ends must
be scrubbed clean with cotton alcohol pads before
injecting the dry treatment. If the teat ends are not
cleaned properly, you may inject into the udder very
high numbers of bacteria, which would overwhelm the
antibiotic just administered. Unsanitary treatment
procedures cause rather than eliminate mastitis.

Management of dry cows also is very important in
mastitis control. If dry cows are exposed to muddy or
dirty conditions, risks of mastitis will increase. This
is especially true at the time of calving; cows are
under much stress during this period and if an udder
is exposed to wet dirty conditions, mastitis will
increase. If you believe that your dry cow therapy
program is ineffective, it may be. because of poor
treatment procedures and/ or improper management
of the cows during the dry period and at calving.

Culling

Culling cows for mastitis is effective in eliminating
mastitis in the herd. Cows that have been treated
many times in a single lactation are prime candidates
for culling, as they may no longer be profitable
because of discarded milk and antibiotic costs. It is
usually more profitable to carry out preventive
mastitis control procedures and cull only old chronic
cows rather than to try and control mastitis by routine
culling.

Summary

Mastitis is a very costly disease, but losses can be
reduced greatly by following an effective control
program, which should include the following items:

1. Handle cows gently to achieve highest
production.

2. Follow proper milking procedures, milk clean,
dry udders, apply milking units properly, and
make adjustments to prevent the admittance of
air into the teat cup liners and prevent liner slip.


Page 8


3. Dip cow's teats after milking to prevent new
infections.

4. Treat all cows going dry with an approved dry
cow drug in commercially prepared tubes to
eliminate existing infections and prevent new
infections during the dry period.

5. Cull chronically infected cows.

MILKING MACHINE FACTORS

Research has demonstrated that "liner slip" is one
area in which the milking machine may increase
mastitis. This is when air is admitted through the top
of the teat cup. Milk and bacteria, if present, may be
propelled into the teat end of an adjacent teat, thus
causing a new bacterial infection. Also, the use of
malfunctioning pulsators can cause teat end damage
and increased the rate of new infection.

The milking machine has little effect on mastitis
if properly operated and functioning according to the
manufacturer's specifications. Clearly though, when
operated improperly, milking machines can have a
role, and malfunctioning equipment can cause mastitis
in several ways. If the pulsator is dirty and does not
function properly, this will cause the massage phase
to be eliminated with the teat end being damaged. A
vacuum controller that is dirty also will not function
properly and again damage the teat end. Damage to
this entry area for organisms increases the risk of
mastitis.

COMPONENTS OF THE MILKING SYSTEM

The Vacuum Pump

The vacuum pump is the heart of the milking
system. Its purpose is to remove air from the system,
thus creating a vacuum. Pump capacity is a measure
of how fast the pump can remove air and is,
therefore, measured in cubic feet of air per minute
(CFM). Pump capacity can be expressed as American
Standard (ASME) or New Zealand Standard (NZ).
One CFM ASME equals 2 CFM NZ. It is similar to
measuring the pumping capacity of an irrigation
system in gallons per minute. Since the rate at which
a pump can remove air depends on the vacuum level,
all pump capacity ratings are standardized by
measuring them at 15 inches of mercury. At that
vacuum level, a pump removes air at a constant rate.







Milking Machine and Mastitis Control Handbook

The vacuum pump needs to be able to remove air
at least as fast as it is let in during milking (air
usage) in order to help keep the vacuum level
constant. If air enters the system faster than the
pump can remove it, the vacuum level will drop. If
pump capacity is greater than air usage (which should
always be the situation), the excess air pumped must
be let in through the vacuum controller (regulator).

The balance tank or vacuum reserve tank serves
two functions. First, it acts as a cushion to absorb any
sudden inrush of air, which might result in a vacuum
drop. Second, it acts as a trap for liquid while the
system is operating, thus protecting the pump from
internal damage. If two pumps are running the
system, each should be connected to the balance tank.
Usually, only one balance tank should be used.
Excess tanks in the system create dead spots and
interfere with the vacuum controller's ability to create
a stable vacuum in the system.

Our recommendation for pump capacity is 30
CFM ASME to run the system plus 1.5 CFM/milker
unit. This is a minimum and is for usable CFM, not
pump CFM. This makes it very difficult to size a
system since you must know the amount of leakage in
the system before you start. Most systems in Florida
have large enough vacuum pumps. If you are
concerned that you don't have enough vacuum, you
might try checking for leaks. In Table 2, we see the
capacity of systems found in the Florida survey.

Table 2. Pump capacity CFM/unit ASME at 15 inches Hg.

CFM/unit Number of herds

<5 7
5-10 27
10+ 5

Average CFM/unit = 7.5; range 3.5 13 CFM/unit.


Leakage in the vacuum system should not exceed
10% of the vacuum pump capacity. To determine the
amount of leakage, all units are removed from the
system, and the air flow is measured at the receiver
jar. Leaks are determined by subtracting the CFMs
measured at the receiver jar from the actual pump
capacity.

In Table 3 (below), we see that Florida dairies
have more leakage in their systems than is desirable.
Only two of the 39 dairies surveyed had systems which
met the standard.


Page 9


Once you remove leakage from pump capacities,
you will see that the usable CFMs per unit is much
lower. Excessive leakage can be quite expensive since
you may need a larger pump to stay ahead. Most
leaks are found in the balance tank, especially if it is
old and rusty and has long plastic lines that sag and
come unglued. If you would like to check your
system for leaks, take a piece of plastic wrap and
place it loosely around the pipe joints. The plastic
wrap will be sucked around the pipe joint wherever it
is leaking.

Table 3. Leaks in vacuum systems, CFM ASME.

Percent CFM leaks Number of herds

< 10 2
10-19 8
20-29 16
30-39 8
40-49 1
50+ 3


Table 4 describes usable CFMs per unit, or pump
capacity minus leakage. This is the vacuum available
for milking.

Table 4. Usable CFM/unit, measured at the receiver jar.

CFM/unit Number of herds
< 5 17
5-10 22
10+ 0

Average usable CFM/unit = 5.6; range 2.5 9.5
CFM/unit.


Thus, on the average, Florida dairies had
sufficient pump capacity; however, those on the low
end of the range should observe their vacuum gauge
regularly to insure that line vacuum remains stable.

Vacuum Pump Maintenance

1. Check belts replace if worn or oil-covered, and
keep tight.
2. Keep the motor clean.
3. If you have an oil reclaimer, clean the filter.
4. If you have a water pump, replace the water
hoses at the first sign of leakage. Many of them
get clogged with algae or scum. This may even
burn the pump up if it doesn't get enough water.







Milking Machine and Mastitis Control Handbook

5. Check balance tank. The drain on bottom
should seal off. If old and rusty, replace it.

Summary

Most Florida dairies have large enough vacuum
pumps, but have an excessive number of leaks.
Before you buy a new vacuum pump, make sure that
leaks are not the cause of your low capacity. Worn or
loose belts also contribute to low pump performance.

Vacuum Controllers (Regulators)

A survey of Florida dairies revealed that an
unacceptably high percentage of vacuum regulators
were not working properly. This condition can easily
translate into a severe mastitis problem. In this
section, we will examine the role of the controller and
describe how to maintain it and check for
malfunctions.

The vacuum pump removes air from the system
at a constant rate, but air is used at a highly variable
rate in the milking operation. Vacuum controllers are
installed in the milking system to hold the vacuum
level constant. The controller does this by admitting
variable amounts of air into the system. When little
air is used in milking, more is allowed in by the
controller. If no air is let in, it could create a vacuum
of nearly 30 inches Hg, much higher than you want
for milking. If excess air is allowed to enter the
system, the line vacuum will drop below the desired
level.

A good quality controller can sense very small
drops in vacuum, which occur as air usage increases,
and responds by admitting less air into the controller.
This keeps the vacuum level constant. The controller
should be able to hold the vacuum constant over its
whole range of air flow capacity, and, when necessary,
it should be able to shut down so that almost no air
is admitted. The capacity of the controller should be
more than the capacity of the vacuum pump.

Types of Controllers

Diaphragm-type controllers generally have the
ability to sense small changes in vacuum, respond
quickly, and hold the vacuum constant over their
whole range of capacity. The most common
diaphragm controllers are the Sentinel, Westfalia,
DeLaval Servo, and D.E.C. Servo. The Surge
Equalizer II is quite acceptable also although it is a
spring type.


Page 10


Old dead weight controllers are not very sensitive
and they should be replaced. A million-dollar dairy
should not be ruled by an old five-dollar controller.

Location of Controllers

The controllers should be placed in the system
according to manufacturer's recommendations and
placement will differ according to manufacturer.
Controllers usually are placed on the main vacuum
line that runs from the pump to the trap or the
balance tank. It is important that it be located in a
clean area that also is accessible for service.
Installation in the parlor usually is not satisfactory
because of the noise it produces. Some controllers
must be double elbowed if installed on the balance
tank. Many have sensors as part of the unit. They
must be located in front of the controller and must
have a correct length of tubing between the sensor
and controller. Because of the complexity of those
controllers, it is important that they be installed
according to directions.

Checking the Response of the Controller

If you have your system analyzed, be sure to have
the controller response checked. This may be done
by removing the probes and placing an orifice
flowmeter in the receiver jar, admitting air in 10 CFM
bursts. There should not be more than one-half inch
change up to 90% of the system's capacity. If
equipment to check your controller is not available
and you keep your controller clean and it is of the
newer type, you should have no problems, as long as
you can see no fluctuation on the vacuum gauge while
milking. If you have the old dead weight controllers,
you do not have to check them. They were not
responsive when they were new--replace them.

Maintenance

Because of the complexity of these controllers,
follow directions for cleaning. If the unit has filters,
clean them when they are dirty, usually once a month,
or more often if located in a dirty area, or you have
a large pump. Large pumps require that all excess air
must come through the controller. Most controllers
that are fitted with filters must also be washed
internally. In some, only the bottom half is washed
while others may be completely washed. Most
controllers need no lubrication and should not be
oiled, which causes dirt and dust to collect and clog.







Milking Machine and Mastitis Control Handbook


Summary


Pulsation Rate


Vacuum controllers are a very important part of
the milking system. No dairy should have an old
controller, since new models are much more sensitive.
Controllers should be installed correctly and kept
clean so they function properly. Maintainance costs
are a small price to pay to insure against a major
mastitis problem.

Pulsators

The pulsator is the device that alternates vacuum
and atmospheric air between the liner and shell and
is responsible for the milking process. Vacuum at the
teat end removes the milk by a pressure differential.
This is called the open or milking phase.

The massage, or rest, phase begins when the
pulsator admits atmospheric air in the chamber
between the liner and shell. This collapses the liner
on the teat end and provides massage to the teat.
The massage cycle is necessary because while the milk
is removed during the milking cycle by vacuum, this
vacuum also draws blood and body fluids down into
the teat. Without adequate massage, the teat and teat
end may be damaged, thus causing an increase in
mastitis.

This action makes the pulsator very important in
the milking process. If the milking phases are not
performed adequately, quarters will not be milked or
milked very slowly. If the massage phase does not
take place, edema of the teat will occur and the
quarter will not be milked properly. In addition, teat
end damage will occur. Either situation is bad for
udder health.

The mastitis survey indicated that only 25% of all
dairies in Florida had all pulsators working properly.
Conversely, 75% of the dairies had malfunctioning
pulsators.


Type of Pulsators


* Electric usually direct current, constant
pulsation. These are most common in Florida.

* Pneumatic these run by vacuum. Most don't
function well in Florida because of high humidity
and feed dust.


Pulsation rate is the number of times per minute
the milk phase and the massage phase occur (the two
phases equal one cycle). The most common rates are
between 44 and 60 pulsations per minute. Forty-four
pulsations per minute is quite common in Florida, but
this is slow milking. Recent research results have
demonstrated that 60 pulsations per minute may be
the best choice.

Pulsation Ratio

Pulsation ratio is the proportion of one cycle that
the milking machine is in the milking phase versus
the massage phase. Most common ratios are between
50:50 and 70:30. In theory the higher the ratio, the
faster that milking will take place; 60:40 seems to be
the most common in new installations.

Analysis of Pulsators

There are several types of equipment used to
check pulsator performance. Earlier machines used
bellows and did an adequate job of graphing pulsator
function. However, more advanced electronic testing
equipment is now available. Both are acceptable to
determine pulsator function. All equipment dealers
and some veterinarians have this equipment.

Pulsators should be checked regularly. In Florida,
where dairies are large, it would be wise for most
dairies to buy their own equipment and check all
pulsators each month.

If you clean your pulsators each month, replace
rubber parts. If all pulsators sound the same when
running, they are probably working properly. Clean
pulsators are very reliable. Remember that, as with
vacuum controllers, pulsators need not be eligible for
social security before they are retired. If they are old
and beat up, buy new ones.


Pulsator Maintenance


Pulsators should be cleaned at least once a month
in Florida. Our unique herd size, hot humid weather,
and the use of dusty feeds are very hard on these
machines. If the small air inlet is blocked, no air will
be admitted, no massage takes place, and the teat end
of every cow milked by that unit gets damaged.

Epoxy-sealed pulsators may be cleaned by sucking
water through the hoses. Make sure that the air inlet


Page 11







Milking Machine and Mastitis Control Handbook

gets washed during this process. Other types of
pulsators should be taken apart and cleaned monthly.
Rubber piston caps should be replaced every 6
months.

Many new installations now have filtered
pulsation air. This is an excellent idea and should
decrease the frequency ofrequired pulsator
maintenance. But even filtered types should be
dismantled and cleaned, with rubber parts replaced
every 6 months.

Summary

With 75% of the dairies in Florida having
malfunctioning pulsators, mastitis losses probably are
high in these herds. To prevent disease, clean
pulsators every month. Most pulsators do not
malfunction because they are mechanically faulty, but
because they are dirty.

The Milking Cluster

The cluster includes the liner, shells, and claw.

Types of Liners.

* Most liners used in Florida are one-piece
narrowbore types and should be replaced after
1200 cow milkings.

Stretch liners are used by a few dairymen in
Florida. They should be replaced after 500 cow
milkings.

Silicone liners also are available and will last 6000
cow milkings. They are very expensive initially,
but because of their extended life, their cost per
milking is equal to or less than regular liners.

Liner Shapes

Round is the most common shape in Florida.
Square liners also are quite popular in some areas of
the state. Shape of liner used is more a matter of
personal preference than a result of scientific
evidence as to which is best.

One of the most important management
considerations for liners is the frequency with which
they are changed. The reason for replacing liners
after the recommended number of milkings is that
they stretch and no longer provide adequate teat
massage.


Page 12


Formula for determining number of days to use
liners:

Liner life x no. of units n o
Times/day milking x no. cows in herd

For example, using liners with a 1200 milking life,
20 units, twice a day milking, and 500 cows:

1200 x 20 = 24 days of liner life
2 x 500

Because of the large number of cows milked in
Florida, it usually is more labor efficient to leave the
liners on the units until it is time to discard them,
rather than going to all the trouble of dismantling
them each week and resting them for a week. This
works fine up north where the dairyman milks 30
cows with three units two times per day.

Liner Vents and Claw Vents

It is very important to vent the milking cluster.
This facilitates the movement of milk away from the
claw and increases milking speed and prevents
flooding of the claw.

Many liners used in Florida are already vented
when purchased. If the liners are vented the claw vent
should be blocked off, but this is easier said than
done. Stainless steel claws may be silver-soldered
shut; epoxy glue may work for a limited time.
Superglues have been known to shatter some plastic
claws.

If both the liners and the claws are vented, too
much air is admitted and this decreases teat end
vacuum and causes too much turbulence inside the
claw. This should be avoided if at all possible. It is
also advisable to check the vents at each milking to
determine if they are open.

Types of Claws

Most claws today are of adequate size and
capacity. Size and shape of claws used are a matter
of personal choice. Some people prefer stainless
steel to plastic.

New Claw Designs

The quarter milker has a separate chamber or
milk tube to separate milk from each quarter. This
may prevent cross-contamination by mastitis. If







Milking Machine and Mastitis Control Handbook

you're in the market for new claws, this might be a
good choice.

Claw Shut-offs

One of the most important components is a
device to shut off the vacuum to the teats before
removing the unit from the cow. Unfortunately, this
type of device is not on most claws or is not used if
installed. A hose clamp shut off also will accomplish
this task. One advantage of automatic take-offs is
that they shut off the vacuum before machine
removal.

Research has shown bad effects when the units
are removed without breaking the vacuum. This
means that bacteria may be propelled into the teat
end and cause mastitis.

Maintenance of Liners and Claws

Liners should be changed according to directions.
Claws should be washed externally daily. The vents
should be checked at each milking. If the claws have
gaskets, they should be replaced once a year.

Summary

The cluster is a very important part of the milking
system. Replacing liners at prescribed intervals,
keeping vents open, and shutting off vacuum to the
teats before removing the unit will help reduce
mastitis losses.

Line Vacuum

The vacuum level at which cows are milked has a
dramatic effect in the milking operation. You need
a reliable means to measure your system vacuum
level. The most common method is with a vacuum
gauge, but the most accurate is with a mercury
manometer. Both devices can give distorted readings.
Gauges get wet and/or dirty and lose accuracy. If the
gauge reads the same when the pump is on or off, or
does not go back to zero when the pump is off, it
needs replacing. Mercury manometers can collect
water and give distorted readings.

Although mercury manometers are very accurate
and are preferred for that reason, they may also pose
a health hazard. Mercury is toxic, and if the
manometer should break, the mercury could be drawn
into the vacuum system and contaminate the milk.
The manometer could break and mercury might get


Page 13


on someone's hands or body, causing harm. If you
have a mercury manometer, use caution.

The most reliable method for vacuum
measurement is using one gauge in the parlor or flat
barn and another in the office or other clean area.
Measure at each milking, and if they both give the
same reading, they probably are correct. Have your
milking equipment dealer check them.

The vacuum level of the system should be
measured from the main vacuum line, not the
pulsator line. Measuring on the pulsator line will give
false readings by measuring fluctuations from pulsator
action.

The vacuum gauge is an excellent tool for
analyzing the milking system. It can be used to check
the vacuum level at each milking, making sure it is at
the prescribed level. A rise in vacuum level is an
indication that the vacuum controller is dirty.

If the vacuum level fluctuates up and down, this
indicates that the controller is dirty and sticking and
is causing vacuum fluctuations. If the controller is
clean and working properly and the vacuum level
drops, this means a shortage of pump capacity. This
may result from worn or loose belts on the pump, or
your pump needs repair or replacement.
Additionally, it could be caused by leaks developing in
the system. If the vacuum gauge or manometer is
suspect, replace it.

The old rule of thumb has been to set the vacuum
level at 12.5 inches Hg for low lines and 14-15 inches
Hg for high lines. Little research data are available
on the optimum level. A system set lower than 11
inches Hg will cause units to fall off the cow at peak
milk flow. Research has demonstrated that vacuum
levels above 15 inches Hg damage teat ends, a
precursor to mastitis organism entry.

To eliminate liner slip or units falling off, raise
the vacuum level until it stops, as long as the vacuum
level does not exceed 15 inches Hg. If units continue
to fall off, you may wish to consider using different
liners.

In Florida, where most cows are being milked 3
times a day, 15" Hg may be the best choice of vacuum
level. Raising the vacuum also may increase milking
speed, and most milkers find that eliminating liner
slip, means that units stay in place.







Milking Machine and Mastitis Control Handbook

Milk Meters

If you are on DHI, or use milk meters on weigh
day, nobody has to tell you what a problem it can be
to milk on these days. This is especially true if you
milk at a low vacuum level, because milk meters
further decrease the vacuum level at the teat end.
The milk meter is a constriction in the line, because
it has several chambers for the vacuum to go around.
The problem ia compounded if you do not have
adequate pump capacity or the vacuum controller is
sticking. Inadequate pump capacity will drop the
vacuum level in the system when air usage exceeds
pump capacity. A sticking controller at a lower
setting than the vacuum level will cause the same
problem.

The best way to get through weigh day is to
increase vacuum level 2 inches if below 15 inches Hg.
Remember to restore the original setting after the
meters are removed so you don't damage teat ends.

The first step to ensure proper line vacuum is to
install reliable gauges. Under Florida conditions that
is best achieved by installing one vacuum gauge in the
milk room and one in the parlor.

Line vacuum or vacuum level is very important to
udder health since liner slip and fall-offs are reduced
at 15 inches Hg. Remember not to exceed this level.
Replace malfunctioning gauges. One of the easiest
ways to increase milking speed, prevent fall-offs, and
have a smooth running test day, is to increase the
vacuum level.

Milk Lines, Vacuum Lines, Pulsator Lines,
and Balance Tanks

The sizing of the lines or pipes in the milking
system is important to provide proper milking
vacuum. Systems that are not balanced (that is, the
lines are not compatible with vacuum pump size) may
cause measurable vacuum differentials in the system
and make vacuum level control difficult. Restricted
pipes not only can cause unstable vacuum conditions
but they may even cause losses of vacuum capacity of
the pump from increased vacuum levels at the intake.
Installing pipes larger than necessary serves no useful
purpose.


Page 14


Milk Lines

There is still much confusion over milk line size.
The 3A standards listed in Table 5 are probably not
relevant. Carrying capacity is influenced greatly by
the slope of the line. A 1.5% slope is probably the
most effective. To determine if you have adequate
line size, measure the vacuum in the milk line. If it
does not vary by more than 0.6" Hg, it's adequate.

Table 5. 3A standards for milk lines.

Units per slope Milk line size
(diameter in inches)

2 1.5
4 2.0
6 2.5
9 3.0


Vacuum Lines (From the Pump to the Trap)

The most critical length of pipe is from the pump
to the vacuum controller or controllers, where the
highest volume of air is moved in the system. The
vacuum controller admits air into the system, which is
exhausted through the vacuum pump. If a 200 CFM
pump is used, only the CFMs actually used are in the
system. The rest go in through the vacuum controller
and out through the pump. In order to keep the
vacuum under control, this pipe must be of sufficient
size to keep air velocity low enough so that the
vacuum controller can function properly and keep the
vacuum level constant.

Air velocity depends on the diameter of the pipe
and the length of the pipe from the pump to the
vacuum controller.

If a vacuum pump with a 20 HP motor or 200
CFM only has a 3-inch outlet, keep the distance
between the pump and the vacuum controller as short
as possible. In most installations, this distance is
usually less than 50 feet. If a large 20 HP vacuum
pump has a great distance between the pump and the
controller, it might be wise to move the controller
closer to the pump.







Milking Machine and Mastitis Control Handbook

Several important factors affect installing a main
vacuum supply line. First, install a Y or tee with a
shut-off valve (gate or slide) next to the vacuum
pump. With these, the pump capacity can be checked
easily with a flowmeter by the dealer or the person
analyzing the milking system. The second is to install
tees instead of elbows in parts of the line. This
allows washing the lines with a hose and water.


Pulsator Lines


Page 15


The problem with oversized or multiple balance
tanks is that they interfere with the vacuum
controller's ability to keep vacuum level stable in the
system. Today's sensitive, fast acting controllers have
the ability to control the whole system
instantaneously. Balance tanks create big vacuum
pockets and may interfere with the controller's ability
to regulate.


Summary


Much confusion still exists on the proper size of
pulsator lines. The latest research indicates that most
pulsator lines are oversized. Up to 20 pulsators can
be used on a 2-inch line. A 3-inch line will handle
20+ pulsators. Research also has shown that the line
need not be looped. A pulsator uses only about 1
CFM in the milking process. This is a small amount
of vacuum, so the pipe need not be large.

In Florida, where most milking systems are large,
the use of 3-inch plastic pipe is common. The
advantage is in the structural stability provided. The
pipe does not sag as readily as smaller plastic pipe,
and it is easier to tap pulsators into a 3-inch line.

Pulsator lines should be installed with tees and
caps so that they can be cleaned out with a hose and
water. The pulsator line should lead directly into the
main balance tank. It does not need its own separate
balance tank.

Balance Tanks

The role of the balance tank, or vacuum reserve
tank in the milking system often is misunderstood. In
the past, it was called a reserve tank because vacuum
pumps usually were very small and this tank provided
a reserve of vacuum to draw from if a milking unit
fell off. The tank also acted as a trap to keep milk
and cleaning solutions out of the vacuum pump.

Most modern milking systems use a 50 gallon
reserve tank. The balance tank acts as a trap. It is
needed when two vacuum pumps are installed on a
system and provides a means of plumbing the pulsator
lines into the system. The tank needs to hold no
more than 40-50 gallons. It can be made of plastic,
stainless steel, or galvanized metal. It should have a
self closing drain on the bottom for liquids when the
pump is off. This drain valve should be designed to
close tightly, since otherwise a large vacuum loss
could occur.


Today's modern milking systems should be
designed so that all components are compatible. The
milk line should be looped and have 1-1.5 inches of
slope per 10 feet. A single line is usually easier to
keep clean than a double line.

The main vacuum line should be of sufficient size
and easily cleaned. The pulsator lines should be
sturdy to prevent sags and be cleanable. The balance
tank keeps liquids out of the pump and also is needed
for a two-pump system. The practice of making
everything larger than needed not only is expensive,
but is not as efficient as a balanced system.

PARLOR AUTOMATION AND OPTIONAL
EQUIPMENT

As the time comes to build a new milking facility
or remodel an existing system, you will ask important
questions. What equipment should be added to
improve labor efficiency? Will new equipment reduce
mastitis in the herd?

Much of the new equipment is very expensive.
Labor requirements may be less in number of people
employed, but dairy workers may need to be more
diligent to operate and maintain this equipment. If
your present milking equipment is working properly
now, the addition of new equipment will not reduce
mastitis. If mastitis is due to poor management
practices -- carelessness, dirty conditions, and
malfunctioning machines -- changing equipment will
not cure the problem.

Automatic Take-off Units (ATOs)

Many improvements have been made in ATOs
since they first were introduced. Reliable solid state
controls have replaced old electronics.

ATOs can reduce labor requirements. When they
are first installed, some old cows will not milk out
completely. Your milkers must be alert to recognize







Milking Machine and Mastitis Control Handbook

this and reapply the unit to partially milked cows.
Heifers usually milk out well with ATOs and once
trained will continue to do so throughout their life as
long as they do not get injured teats.

The role of ATOs in reducing mastitis is
questionable. It was thought that overmilking caused
increased mastitis, but research has shown that
overmilking is not a factor in increasing mastitis in
herds with relatively low percentage of infected
quarters. Overmilking increases the length of time for
organisms to cross-contaminate into another quarter
of the same cow. If presently you have a highly
infected herd, ATOs will not eliminate the high level
of infection. Other management practices must be
implemented. One big advantage of ATOs is that
vacuum is shut off before units are removed, thus
preventing mastitis. In large herd situations the use
of ATOs is practical. It allows fewer milkers and
cows will be milked the same way at every milking.

Backflushers

Backflushers were introduced several years ago in
an effort to control Mycoplasma mastitis. They
usually are very expensive to purchase and maintain.
Most automatic backflushers have four or five cycles
-- water rinse, iodine rinse, clear water rinse, and
positive air dry cycle.

It was thought that sanitizing the liners between
each cow would stop the spread of Mycoplasma
mastitis. Field observations have shown that this may
be the case. In herds where every cow is cultured for
the presence of mycoplasmas and positive cows are
culled from the herd, these same observations might
have been made in the same herds if no backflusher
were present. Other field observations have been
made in which Mycoplasma increased in herds with
backflushers where they did not sample and cull the
positive cows. Little or no research data are available
to determine if backflushers will stop the spread of
Mycoplasma mastitis.

Research from the Universities of Florida,
Kentucky, and Pennsylvania demonstrate that
backflushers reduce the number of bacteria in the
liner between cows milked, but this does not reduce
the number of bacteria on the teats of the cows.
Infected teats are the problem to solve, not
contaminated liners. There is some evidence that
backflushers will reduce the spread of some
contagious organisms, but this can be accomplished at
a much lower cost by teat dipping.


Page 16


British researchers have compared the use of teat
cup pasteurization between milking of each cow
versus no pasteurization, and found that the former
gave a small decrease in mastitis, but not enough
difference to pay for the cost.

Because of the high initial cost and daily
maintenance of backflushers, and because their
benefits have not been effectively demonstrated, the
purchase must be questioned.

Quartermilkers

Another new product on the market is the divided
claw or quartermilker. The purpose of this device is
to prevent the cross-infection of mastitis from one
quarter to another during the milking process. If you
have a low infection level, not much benefit would be
seen using this type of claw because there is little
mastitis to spread. If you have a highly infected herd,
again, not much difference will be seen since most of
the quarters already are infected.

The only problem that might arise with this type
of claw is its durability. Some of them have four
individual hoses connecting quarters to the milk line.
This increases the chance of them coming apart. The
unit also should be able to withstand being stepped
on by cows.

While no dramatic evidence has been found that
the use of a quarter-milker will greatly reduce
mastitis, it certainly couldn't hurt. If you are in the
market for new claws anyway, they might be a wise
choice. If your present claws are in good condition,
you may wish to wait until they need replacing and
then try the divided claws to see if there is any
benefit.

Filtered Pulsator Air

Many new installations are being equipped with
filtered air. This is no more than a length of 3-inch
plastic pipe with all the pulsator air in-lets connected
to it by a short length of hose,and one or more air
filters on the pipe. Not only is this a good idea for
new installations, but also for existing systems. The
cost of this addition is very low and the benefits are
great. Remember that 75% of the dairies in Florida
have at least one malfunctioning pulsator. The main
reason for malfunctioning pulsators is that they are
dirty. The filtered air will reduce greatly the amount
of dirt that enters the pulsators. Because filtered air
will not protect pulsators when the hose becomes







Milking Machine and Mastitis Control Handbook

disconnected and sucks up manure, they should be
cleaned whenever this happens, either by running
water through the pulsator hoses in sealed pulsators
or by dismantling other types. Take apart pulsators
every 6 months for cleaning and inspect rubber parts.
Change dirty filters or the pulsators will not function.
To prevent moisture collection in this line from
entering the pulsators, position the nipples on the
filtered air line upward.

Summary

Purchase of new equipment, when needed, to
upgrade a milking system is usually a wise decision.
Automatic take-offs, if used properly, can reduce
labor requirements. Other equipment may or may
not have value in reducing mastitis. There is no shot
in a bottle or piece of equipment that can overcome
poor management practices.

KEEPING THE SYSTEM CLEAN

Cleaning the milking system is one of the most
important chores on the dairy. High bacteria counts
usually are caused by dirty equipment or poor cooling
of the milk. Cows with mastitis usually are not the
cause of high bacteria counts.

Cleaning the pipeline should begin as soon as
milking ends, not after the parlor or flat barn is
washed. Just as the parlor is harder to clean after it
dries, the pipeline also is more difficult to clean.

The first step is to pre-rinse the system. Use
95-100 degrees Fahrenheit water and discard this
water.

Next, wash the system for 8-10 minutes with water
at least at 160 degrees Fahrenheit and the correct
amount of chlorinated cleaner. The water
temperature should not drop below 110 during the
wash cycle; if it does, fat may be redeposited back on
the pipelines. If the water is very hard, use more
cleaner or a water softener to supply water for
washing the pipeline and the bulk tank.

Every dairy should have a thermometer. Use it
every month to check the water temperature in the
wash vat at the beginning and end of the wash cycle.

Water temperature at the tap does not always
indicate what the used wash water temperature will


Page 17


be. Multiple hot water heaters may be set at lower
temperatures. Use the hottest water in the rinse
cycle, especially in systems with tube or precoolers.
Also, if you have an insufficient hot water supply, the
hot water may be gone before the wash cycle has
started. If the bulk tank also is washed at the same
time as the pipeline wash, you will need a very large
supply of hot water to clean both systems.

The next step is an acid rinse to neutralize
chlorine residues and prolong the life of the rubber
parts of the system. You will also prevent mineral
deposits, water spotting, and milk stone deposits. The
water temperature for the acid rinse should be
between 95 and 110 degrees.

Immediately before milking, the system should be
sanitized with a product made especially for dairy
installation. Liquid bleach or unknown bulk chlorine
may work in the swimming pool but do a poor job in
the pipeline.

The air injector also is important for wash-up. If
you don't have one, or it doesn't work well, you will
have a high bacteria count. Air injectors slug the
water for cleaning the top of the pipeline which
otherwise won't get washed.

The pulsator lines and main vacuum line from the
trap to the pump also should be washed every 6
months. High bacteria counts occur because of dirty
vacuum lines, especially if the trap keeps running over
with milk.

High bacteria counts due to poor or slow cooling
of milk may result from dirty coils or low gas in the
system. It is easy to detect poor cooling if you have
an accurate thermometer on the tank.

MILKING EQUIPMENT CLEANING

A survey of milking equipment in Florida
revealed that many of the pulsators and vacuum
controllers were not functioning properly. Research
has demonstrated that major mastitis problems can
occur with malfunctioning pulsation and vacuum
controllers. The most common cause of these
malfunctions is a lack of regular maintenance. If you
have not performed these maintenance chores in
some time, now would be a good time to start. Here
are some guidelines to follow.







Milking Machine and Mastitis Control Handbook

disconnected and sucks up manure, they should be
cleaned whenever this happens, either by running
water through the pulsator hoses in sealed pulsators
or by dismantling other types. Take apart pulsators
every 6 months for cleaning and inspect rubber parts.
Change dirty filters or the pulsators will not function.
To prevent moisture collection in this line from
entering the pulsators, position the nipples on the
filtered air line upward.

Summary

Purchase of new equipment, when needed, to
upgrade a milking system is usually a wise decision.
Automatic take-offs, if used properly, can reduce
labor requirements. Other equipment may or may
not have value in reducing mastitis. There is no shot
in a bottle or piece of equipment that can overcome
poor management practices.

KEEPING THE SYSTEM CLEAN

Cleaning the milking system is one of the most
important chores on the dairy. High bacteria counts
usually are caused by dirty equipment or poor cooling
of the milk. Cows with mastitis usually are not the
cause of high bacteria counts.

Cleaning the pipeline should begin as soon as
milking ends, not after the parlor or flat barn is
washed. Just as the parlor is harder to clean after it
dries, the pipeline also is more difficult to clean.

The first step is to pre-rinse the system. Use
95-100 degrees Fahrenheit water and discard this
water.

Next, wash the system for 8-10 minutes with water
at least at 160 degrees Fahrenheit and the correct
amount of chlorinated cleaner. The water
temperature should not drop below 110 during the
wash cycle; if it does, fat may be redeposited back on
the pipelines. If the water is very hard, use more
cleaner or a water softener to supply water for
washing the pipeline and the bulk tank.

Every dairy should have a thermometer. Use it
every month to check the water temperature in the
wash vat at the beginning and end of the wash cycle.

Water temperature at the tap does not always
indicate what the used wash water temperature will


Page 17


be. Multiple hot water heaters may be set at lower
temperatures. Use the hottest water in the rinse
cycle, especially in systems with tube or precoolers.
Also, if you have an insufficient hot water supply, the
hot water may be gone before the wash cycle has
started. If the bulk tank also is washed at the same
time as the pipeline wash, you will need a very large
supply of hot water to clean both systems.

The next step is an acid rinse to neutralize
chlorine residues and prolong the life of the rubber
parts of the system. You will also prevent mineral
deposits, water spotting, and milk stone deposits. The
water temperature for the acid rinse should be
between 95 and 110 degrees.

Immediately before milking, the system should be
sanitized with a product made especially for dairy
installation. Liquid bleach or unknown bulk chlorine
may work in the swimming pool but do a poor job in
the pipeline.

The air injector also is important for wash-up. If
you don't have one, or it doesn't work well, you will
have a high bacteria count. Air injectors slug the
water for cleaning the top of the pipeline which
otherwise won't get washed.

The pulsator lines and main vacuum line from the
trap to the pump also should be washed every 6
months. High bacteria counts occur because of dirty
vacuum lines, especially if the trap keeps running over
with milk.

High bacteria counts due to poor or slow cooling
of milk may result from dirty coils or low gas in the
system. It is easy to detect poor cooling if you have
an accurate thermometer on the tank.

MILKING EQUIPMENT CLEANING

A survey of milking equipment in Florida
revealed that many of the pulsators and vacuum
controllers were not functioning properly. Research
has demonstrated that major mastitis problems can
occur with malfunctioning pulsation and vacuum
controllers. The most common cause of these
malfunctions is a lack of regular maintenance. If you
have not performed these maintenance chores in
some time, now would be a good time to start. Here
are some guidelines to follow.







Milking Machine and Mastitis Control Handbook

Daily

Wash outside of milk line, receiver jar and trap,
and claws and hoses.

Two Weeks or 1200 Milkings

Replace liners.

Monthly

1. Remove pulsators and clean them.
2. Replace filters and/or clean vacuum controllers.
3. Wash trap inside and out.


Every 6 Months


1. Monthly cleaning as usual.
2. Replace all pulsator rubber parts.
3. Replace all pulsator hoses, air tubes.
4. Replace receiver jar gasket.
5. Replace all milk hoses.
6. Replace rubber hoses and rubber hose nozzles
used to wash udders (rubber hoses harbor
bacteria).
7. Flush pulsator and vacuum lines.
8. Check belts on vacuum pumps.

Yearly

1. Do monthly and 6-month cleaning as usual.
2. Replace all wash line hoses.
3. Replace trap gasket.
4. Replace wash manifold cups.
5. Replace belts on vacuum pump.

STRAY VOLTAGE AND MASTITIS

Stray voltage had been thought to cause mastitis,
but research results have not shown this to be true.
Stray voltage may increase somatic cell counts
because of irritation. Since the voltage cannot inject
bacteria into the teat, most damage may be exhibited
by cows who are already infected with subclinical
mastitis. These cows may not milk out completely
and advance to clinical symptoms. Thus, the voltage
did not cause the mastitis; it just brought it to your
attention.

Cow's Reaction to Current

Stray voltage can cause behavioral changes in
dairy cows. They may refuse to enter the parlor, kick
while being milked, or show other abnormal behavior.


Page 18


Cows may not drink normal amounts of water when
stray voltage is present. Voltage leak may be in a
pasture water tank, not in the parlor or flat barn.

Dairy cattle are sensitive to 0.5 volt AC or about
2.5 mA milliamperess). Cows react to the current,
not the voltage. The dairy cow's resistance is about
250 to 400 ohms, about 0.1 that of humans. That is
why they feel the electrical currents and you do not.

Measuring Stray Voltage

If you think stray voltage is a problem, make
these checks:

1. Use a high quality volt-ohmmeter that can
separate AC from DC voltage. AC current is
the problem. DC voltage at low levels has little
effect on cows, and all electric pulsators are DC
powered. (To test your voltmeter, hold a small
flashlight battery between the probes of the
meter with the meter on the AC scale. A meter
that responds to DC current on the AC scale
should have a 5 to 10 micro-farad capacitor
located in series in the probes to the meter.)

2. Install a 300 to 400-ohm resistor in parallel with
the meter to duplicate the cow's resistance.

3. Take measurements with an isolated,
copper-clad grounding rod. Place the rod 50
feet from the building, using a 14-gauge copper
wire between the meter and the rod.

4. Measure voltage on the primary and secondary
neutral, the bulk tank, parlor, or stanchions.
Water cups or tanks also should be checked. If
the cows won't drink water, this will cause low
production.

5. If you do find stray voltage with your meter,
have a qualified electrician check your system
thoroughly. Reducing the effects of stray
voltage. Whenever a new parlor is built, embed
wire mesh in the floor and bond all metal
surfaces to the mesh. The grounded mesh
should cover both the stall floor and the pit
area. Also, the mesh should extend into the
holding area to minimize the chance of a
potential difference.

In existing parlors, a number 10 copper ground
wire can be laid in slots cut into the floor, connecting
all metal structures in the parlor. The slots in the








Milking Machine and Mastitis Control Handbook


floor can then be grouted over. Isolating
transformers also can be used in some cases.

Summary

Stray voltage can be very troublesome on dairies.
If you determine there is a problem, contact your
local power company and a qualified electrician to
eliminate the problem. You also can contact your
county agent for AE 55 a fact sheet that gives more
detail on this subject.

SIZING THE MILKING SYSTEM

Vacuum Requirements

The amount of vacuum used to operate the
milking system is quite small, less than 2 CFM per
unit. Extra CFMs are needed to compensate for
vacuum losses that occur naturally in the system: head
loss and resistance of pipes, elbows, etc. Thirty CFM
ASME are needed in any system just to keep the
system operating.

Leaks account for a 10% loss (the difference
between pump CFMs and system CFMs). Milk
meters, unit slippage, air leakage used when applying
the unit, and unit fall-off also consume varying
amounts of vacuum depending on the skills of the
operators.

Stated vacuum requirements vary greatly and are
based on personal bias rather than research. The
usual method is expressing CFMs per unit, which
usually undersizes small systems and greatly oversizes
large systems.

Electric motors that run vacuum pumps are
usually either 5, 7.5, 10, 15, or 20 HP and 1 HP
motors will deliver 10 CFM ASME on an oil pump,
or 7.5 CFM on a water pump. You must determine
the pump size for your vacuum usage range.

For determining the size of vacuum pump
needed, include 30 CFM for running the system, 10
percent loss due to leaks, and 3 CFM per unit for
each unit (2 CFM to milk and 1 CFM added for milk
meters and other losses) (see Table 6, Table 7, and
Table 8). This should provide more than adequate
vacuum for most systems. This does not include extra
capacity for one half of the units open on the floor.
A milking system should not be designed for poor
milking procedures. Adequate milking vacuum level
to prevent liner slip will reduce fall-offs and most


Page 19


automatic take offs will shut off automatically on
fall-offs.

Table 6. Florida Vacuum System Requirements.

1. 30 CFM ASME to run the system.
2. 10% leakage in the system.
3. 3 CFM/unit, including milk meters and usage losses.

Pump HP Oil Pumps Water Pump

5 50 38
-30 to run system -30 to run system
5. leaks 4 leaks
15 for units / 3/unit 4 for units I 3/unit
= 5 units = 1 unit
7.5 75 56
-30 to run system -30 to run system
7.5 leaks 6 leaks
37.5 for units / 3/unit 20 for units / 3/unit
= 12 units = 6 units
10 100 75
-30 to run system -30 to run system
-10 leaks 7.5 leaks
60 for units / 3/unit 37.5 for units / 3/unit
= 20 units = 12 units
15 150 113
-30 to run system -30 to run system
-15 leaks -11 leaks
105 for units / 3/unit 72 for units / 3/unit
= 35 units = 24 units
20 200 150
-30 to run system -30 to run system
-20 leaks -15 leaks
150 for units / 3/unit 105 for units / 3/unit
= 50 units = 35 units

*Numbers expressed in CFMs unless otherwise stated.



Table 7. Pump Horsepower and Number of Milk Units.

No. units with No. units with
HP oil pumps water pumps

5 1-5 1
7.5 6-12 2-6
10 13-20 7-12
15 21-35 13 24
20 36-50 25-35








Milking Machine and Mastitis Control Handbook


Table 8. Parlor Size and Size of Pump Needed (One Unit
per Stall).

Size of Number Oil Pump Water
Parlor of Units HP Pump HP

Double 6 12 7.5 10
Double 8 16 10 15
Double 10 20 10 15
Double 12 24 15 15
Double 16 32 15 20
Double 20 40 20 25
Double 30 60 25 30
Double 40 80 40 50



Milk Lines Size

The following are excerpts from the National
Mastitis Council annual meeting proceedings, 1993
(see Table 5).

Table 9. Number of units per slope.a

% Slope
Milk Line
Size 0.5 0.8 1.0 1.25 1.5 2.0
2 inches 2 3 3 4 4 5
2 5 inches 4 5 6 7 8 10
3 inches 6 9 10 13 16 24
4 nchesb 21 28 32 35 38 43
a Parlor, with units attached every 10 seconds per slope
Peak flowrate = (12lb/min)/cow
Steady air admission = (0.35-0.7 scfm)/unit
Transient air admission = (3.5 scfm)/slope

b Number per 4" line may vary with number of operations



Pulsator Line Size

A 3-inch diameter plastic pulsator line is used for
rigidity and ease of taping for pulsators. There is no
need for a size larger than 3 inches.


Page 20


TROUBLE SHOOTING A PROBLEM HERD

Since mastitis can be caused by man, machine,
and the cow's environment, all items must be checked
to determine its cause.

What is a mastitis problem herd? Any herd that
continually has a cell count above 400,000 cells/ml can
be considered a problem. But herds that have a cell
count of nearly 1 million cells/ml, and are close to
losing their market, are usually considered a problem.

Variations in Clinical Mastitis

The number of cows or quarters treated for
clinical mastitis can vary from herd to herd even
though they may have identical mastitis occurrence.
The time or season of the year also may be a factor.
An average of 1-3% of the cows in the pot herd (per
day) over a year's time is probably typical for a
Florida herd.

An increase or decrease in the number of clinical
mastitis cases may result from a change in the people
doing the milking. If the milkers stop checking for
clinical mastitis, the number will decrease. If no one
had been checking for clinical mastitis and suddenly
started checking, the number of cases would increase
dramatically even though nothing had changed in the
mastitis level of the herd. In many herds, number of
cases increases during hot, muddy conditions when
environmental organisms are the cause.

Do you have a herd mastitis problem, or just a
few cows with a mastitis problem? By recording cows
treated during one consecutive month and comparing
them with the cows treated in the previous month,
you can determine if the same cows are being treated
over and over again. If so, you may consider
removing those cows from the herd.


Stage of lactation and mastitis


If most new cases of mastitis occur at calving, you
should review your dry cow program by asking
yourself these three questions: 1) are all cows dry
treated with an approved dry cow antibiotic? 2) are
teat ends cleaned with cotton and alcohol before
treatment? and 3) are dry cows kept in a clean dry
environment and allowed to calve in a clean dry
place?







Milking Machine and Mastitis Control Handbook

Problem solving when cell count range is
400,000-750,000 cells/mi

1. Clean pulsators.

2. Clean vacuum controllers.

3. Check milking procedures. Are you milking
clean, dry udders and shutting off vacuum to the
claw before removing the unit?

4. Check teat dipping procedures. After milking,
is there any visible dip on the teats? In problem
herds, teat must be dipped with a cup not
sprayed dip to base of udder.

5. Review your dry cow program. Are all quarters
dry treated before going dry?

Problem solving when cell counts are above
750,000 cells/ml

1. Follow procedures 1-5 above.

2. You are in danger of losing your milk market;
you may wish to use the paddle test or use
individual cow cell counts to identify high count
cows. Late lactation pregnant cows can be dried
off early. You may wish to cull late lactation
cows that are not pregnant. If this does not
lower your cell count enough to sell milk, more
drastic measures must be taken. Treating all the
high cell count cows will usually lower the cell
count but, because of the high cost of drugs and
dumped milk, it will be very expensive.

3. Consult your veterinarian, county agent, or
sanitarian for further help. Your county agent
also has other fact sheets available on mastitis
and checking milking equipment.

How to Handle Mycoplasma Problem Herds

You only know if you have mycoplasma if you
sample for it. Since it's untreatable, you should
prevent it, or at least prevent the spread of it.

No sample approach

* Teat dip to stop the spread from cow to cow
during milking.

Use only commercial tubs use no bottle mixes to
treat intramammary.


Page 21


SMycoplasma cows usually exhibit the following
symptoms:

More than one quarter with clinical mastitis.

This mastitis does not clear up with treatment
and the cow does not show any signs of
sickness.

Drop in milk production.

If you routinely cull the above type animals,
mycoplasma will come and go and you will
never know it. It won't spread if you do a
good job of teat dipping and no bottle mixes
are used.

Simple Sample Approaches

* Regular bulk tank analysis.

* When mycoplasma appears:

Make sure you are doing a good job of teat
dipping and use no bottle mixes.

Cull cows: multiple quarters with clinical
mastitis that don't clear, and cows that seem
healthy.

If records are kept of animals entering
milking string, the animals since the last bulk
tank sample can be sampled.

This approach usually will take care of these
problems.

Full Scale Samples

* Expensive.

* Great care in sampling rubber gloves, sanitized
between cows or you will spread from sample
bottle to sample bottle, and think you have an
epidemic when you only have a couple of cows
infected.

Epidemics usually happen by spreading from cow
to cow using bottle mixes. If you have an
epidemic and use bottle mixes, review your pot
herd records these are your mycoplasma cows.







Milking Machine and Mastitis Control Handbook

What Not to Do in a Mycoplasma Crisis

* Panic.

* Sample the whole herd (expensive).

* Rinse milkers with water.

* Buy backflushers.

* Try to separate (unless you have 100's). This
usually changes milking routines and causes many
other problems, and it is not effective anyway.

Trouble Shooting a Herd
with a High Bacteria Count

High bacteria counts usually are caused by poor
cleaning of milking equipment or improper cooling of
the milk and herds with strep. agalactia.

1. Check hot water temperature during the rinse
cycle, it should be cool, not hot. Rinse water
should be discarded.

2. Check hot water temperature in the wash sink at
the start of wash-up. It should be 160 and
110-120 degrees Fahrenheit at the end of the
wash cycle.

3. Is the proper amount of pipe line cleaner being
used? Is the cleaner stored with the cover on?
Chlorine will evaporate if cover is left off.


Page 22


4. Is a dairy sanitizer used before each milking?
Bulk chlorines don't always work.

5. Does the air injector work? If not, poor
cleaning will result.

6. Clean out all vacuum lines, pump to trap, and
pulsator lines with a lye or cleaning solution.

7. Replace every rubber or plastic hose in the
system, including liners.

8. Dismantle and clean the milk pump.

9. Check milk temperature. If high, recharge the
cooling system.

10. If there is a build-up of material in the lines, it
may be necessary to dismantle all milk lines and
clean them with a brush. The bulk tank also
may have to be manually scrubbed to remove
build up.

11. If you have a high somatic cell count along with
a high bacteria count, you may have a cow
problem and you must treat it like a high SCC
problem.










































































COOPERATIVE EXTENSION SERVICE, UNIVERSITY OF FLORIDA, INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES, John
T. Woeste, Director, in cooperation with the United States Department of Agriculture, publishes this information to further the
purpose of the May 8 and June 30, 1914 Acts of Congress; and is authorized to provide research, educational information and
other services only to individuals and institutions that function without regard to race, color, sex, age, handicap or national origin.
Single copies of extension publications (excluding 4-H and youth publications) are available free to Florida residents from county
extension offices. Information on bulk rates or copies for out-of-state purchasers is available from C.M. Hinton, Publications
Distribution Center, IFAS Building 664, University of Florida, Gainesville, Florida32611. Before publicizing this publication, editors
should contact this address to determine availability. Printed April 1994.




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