A STUDY OF EXPERIMENTAL STREPTOCOCCIC MASTITIS
IN DAIRY CATTLE

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A STUDY OF EXPERIMENTAL STREPTOCOCCIC M ASTITIS
IN DAIRY CATTLE

T h esis

S u b m itte d to th e F a c u lt y o f M ichigan S t a t e C olle
o f A g r i c u l t u r e and A p p lie d S c ie n c e i n p a r t i a l
f u l f il l m e n t of th e req u irem en ts fo r
d e g re e of D octor of P h ilo s o p h y

t/*'
C. 3* B r y a n
June,

1 93 7

the

TABLE OF CONTENTS

I n t r o d u c t i o n a n d H i s t o r i c a l R eview

............................

M e t h o d s .................................................................................................

1.
4.

R e s u l t s and D i s c u s s i o n
!•

The s t r e p t o c o c c u s em ployed i n t h i s

s t u d y .............

2 . The p o r t a l o f e n t r y o f t h e s t r e p t o c o c c u s
i n t o t h e u d d e r . . . . . . . . .........................

7.
8.

3 . T h e c o n t r o l o f s t r e p t o c o c c i c m a s t i t i s by
s a n i t a r y m e a su re s and s e g r e g a t i o n o f
i n f e c t e d c o w s . ..........................................................................

10.

4 . The v a r i a t i o n i n c o m p o s itio n o f m ilk
f o l l o w i n g i n f e c t i o n . . ..............................................................

11.

5. The r e d u c t i o n i n t h e q u a li t y , o f m il k p r o d u c e d
b y i n f e c t e d c o w s .................

15.

6 . The v a l u e o f t h e v a r i o u s t e s t s i n t h e d e t e c t i o n
o f e x p e r i m e n t a l l y in d u c e d s t r e p t o c o c c i c m a s t i t i s . 17.
7 . The c e l l u l a r a n d h e m o g lo b in c o n t e n t s o f
b o v i n e b l o o d ...............

19.

8. D ross p a th o lo g y and h is to p a th o lo g y of the
u d d e r s ...............

21.

S u m m a r y . .....................................................................
L itera tu re

c ited

A cknow ledgm ent.

27.
...............

............. ........................................................

/
110617

30.
35.

A STUDY OF EXPERIMENTAL STREPTOCOCCIC MASTITIS IN
DAIRY CATTLE

S trep to co ccic m a s titis

i s a m a jo r d a i r y p ro b le m from

b o t h t h e econom ic an d h y g i e n i c v i e w p o i n t s .
rep o rted th a t q u arters

Shaw a n d B e a m ( 2 7 )

In fe c te d w ith s tr e p to c o c c i produce

a p p r o x i m a t e l y 22 p e r c e n t l e s s m i l k a n d 24 p e r

cent less

b u t t e r f a t th an th e s tr e p to c o c c u s -fre e q u a rte r s .
c ow s a r e

S i n c e m any

in fe c te d in a l l four q u arters a sim ila r decrease in

m i l k a n d b u t t e r f a t p r o d u c t i o n may b e e x p e c t e d a n d h a s b e e n
o b s e r v e d among d a i r y c o w s .

M in n e tt and M a rtin

th e m ilk y i e l d of m a s t i t i s

(24)

stud ied

i n f e c t e d cows a n d r e p o r t e d t h a t

the

r e d u c t i o n o f m i l k y i e l d d u e t o m a s t i t i s was 9 54 p o u n d s p e r
l a c t a t i o n period*
the r e d u c tio n

More r e c e n t l y , W h ite e t a l .

of m ilk y i e l d

(32) r e p o r t e d

of m a s titis - in f e c te d

425 t o 562 p o u n d s p e r l a c t a t i o n p e r i o d .
m ilk p ro d u ctio n of m a s titis - in f e c te d
to th e p ro d u ctio n of m a s titis - f r e e

It

cows a s b e i n g

i s obvious t h a t

the

cows i s r e d u c e d a s c o m p a r e d

cows, e v en th o u g h i n v e s t i g a t o r s

d o n o t e x a c t l y a g r e e on t h e e x t e n t o f r e d u c t i o n .
B ryan and T ro u t

(8)

f o u n d t h a t m i l k p r o d u c e d b y cows w i t h

s t r e p t o c o c c i c m a s t i t i s was i n f e r i o r

i n q u a l i t y a s d e te r m i n e d by

flav o r,

co n ten t, b a c te ria

ch lo rid e

co n te n t,

leucocyte

m ethylene b lu e r e d u c tio n tim e .

N in ety p e r

a herd fre e

and

cent of th e m ilk

s a m p l e s f r o m i n f e c t e d cows i n o n e h e r d w e r e c r i t i c i z e d
a s a l t y f l a v o r , w h i l e o n l y 14 p e r

c o u n t,

as h aving

c e n t o f th e m ilk sam ples from

o f s t r e p t o c o c c i c m a s t i t i s w ere so c r i t i c i s e d .

These

2

l a t t e r a n im a ls w ere n e a r th e

end o f t h e i r l a c t a t i o n p e r i o d

when s u c h c h a n g e s may n o r m a l l y o c c u r*
th e s tr e p to c o c c u s - in f e c te d
m ilk as

O n l y 50 p e r c e n t o f

cows p r o d u c e d a c l a s s one

(good)

ju d g ed by th e m e th y le n e b lu e r e d u c t i o n t e s t ,

as

com pared w i t h 9 8 . 5 p e r c e n t o f t h e n o n - i n f e c t e d cows.
ila rly ,

5 8.5 p e r

Sim­

c e n t o f t h e i n f e c t e d cows p r o d u c e d m i l k

w ith a sta n d a rd p l a t e

c o u n t o f m ore t h a n 1000 a s compared

YJith 5 . 8 p e r c e n t o f t h e n o n - i n f e c t e d

cows.

The d e c r e a s e d

p r o d u c t i o n a n d l o w e r e d q u a l i t y o f m i l k p r o d u c e d b y cows w i t h
s tr e p to c o c c ic m a s t i t i s a re s u f f i c i e n t re a s o n s f o r em phasizing
the

econom ic s i d e

asp ects

of t h e p ro b le m .

In a d d itio n ,

th e h y g ien ic

of th e problem a re im p o rta n t.

The s t r e p t o c o c c i t h a t c a u s e m a s t i t i s h a v e b e e n f o u n d t o
be t h e

c a u s e o f human i n f e c t i o n .

o f hu m an a n d b o v i n e o r i g i n t h a t
e c tio n u s u a lly tak es

These in c lu d e th e s tr e p to c o c c i
cause m a s titis .

th e form of s e p t i c

sore th r o a t

when hum an s t r a i n s a r e c o n c e r n e d a n d i s o l a t e d
th r o a t to g e th e r w ith f u r th e r

cases of sore

B rooks an d T iedem an (5) p r e s e n t

e v id e n c e t h a t m ilk from m a s t i t i s i n f e c t e d
Md i s t r e s s ” , e s p e c i a l l y i n b a b i e s ,
in the m ilk .

ep idem ics

c o m p l i c a t i o n s w h en s t r e p t o c o c c i

of bovine o r i g i n a re concerned.

present

The hum an i n f ­

cow s may c a u s e hu m an

as a r e s u l t

of the to x in s

The e c o n o m i c a n d h y g i e n i c a s p e c t s o f t h e

p r o b l e m a r e g r e a t l y e m p h a s i z e d when t h e i n c i d e n c e o f t h i s
disease

is

c attle

considered.

E i g h t y - s i x p e r cen t of th e h e rd s and 2 6 .2 p e r

cent of a l l

m i l k i n g cows w e r e f o u n d t o b e i n f e c t e d w i t h s t r e p t o c o c c i c

3

m a s t i t i s i n a s u r v e y c o n d u c te d i n a t y p i c a l m i l k shed*
F ig u re s d ealin g w ith the in cid en ce
as rep o rted
paper*

a re p re s e n te d i n th e above

t o g e t h e r w i t h t h e human h e a l t h p r o b l e m s

i n v o l v e d , make t h i s o n e o f t h e ,
d airy c a ttle

of stre p to c o cc ic m a s titis ,

by o t h e r i n v e s t i g a t o r s ,

These d a ta ,

(6),

i f n o t t h e , m ost im p o rta n t

d i s e a s e a t t h e p r e s e n t tim e*

The im p o rta n c e and w ide s p re a d o f s t r e p t o c o c c i c m a s t i t i s
c r e a t e a b ig problem w ith r e s p e c t t o t h e
of th e

in fec tio n *

It

is

e s s e n tia l th at

c o n tro l or e ra d ic a tio n
su c h reco m m e n d atio n s be

b a s e d on an u n d e r s t a n d i n g o f th e f o llo w in g :
1* T h e m a n n e r o f s p r e a d o f t h e s t r e p t o c o c c u s f r o m cow t o
cow o r f r o m some o t h e r s o u r c e t o t h e

cow*

2. The p o r t a l of e n t r y o f t h e s t r e p t o c o c c u s i n t o t h e u d d e r .
3* T h e t i m e when m o s t s p r e a d o f i n f e c t i o n o c c u r s .
deal or th is

A great

i n f o r m a t i o n c a n o n l y be g a i n e d fro m a s t u d y o f

e x p e rim e n ta lly induced s tr e p to c o c c ic m a s t i t i s .
T h e s t u d y wa s u n d e r t a k e n t o d e t e r m i n e :
e n try of th e s tre p to c o c c u s in to th e u d d er,
of c o n tro llin g strep to co ccic m a s titis
in fected

(1)
(2)

the p o rta l of
the p o s s i b i l i t y

by s e g r e g a t i o n of th e

cows a n d t h e e m p l o y m e n t o f s a n i t a r y p r o c e d u r e s i n

h a n d lin g the h e rd ,

(3)

the v a ria tio n in

m ilk fo llo w in g i n f e c tio n

com position of th e

by t h e s t r e p t o c o c c u s ,

(4)

the r a p i d i t y

of th e re d u c tio n in th e q u a l i t y of th e m ilk a f t e r i n f e c t i o n ,
(5)

the v a lu e o f th e v a rio u s t e s t s

in the

m e n ta lly induced s t r e p to c o c c ic m a s t i t i s
t e s t (7)

(b)

in d irect te s ts

(20)

d etectio n of ex p eri­

(a)

d irect-m icro sco p ic

and (c) p h y s i c a l e x a m in a tio n

of

th e udder
ten t

(28),

(6)

th e norm al c e l l u l a r and hem oglobin con­

o f th e b lo o d and v a r i a t i o n s f o llo w in g e x p o su re s and

in fec tio n ,

and (7)

t h e h i s t o p a t h o l o g y o f t h e u d d e r s when t h e

d u ratio n of in fe c tio n is

d e f i n i t e l y known.

M ethods
T h i s s t u d y c o v e r e d a p e r i o d o f two y e a r s
g r o u p s o f t h r e e cows,
each y e a r.

i n v o l v i n g two

two cows a n d a c o n t r o l b e i n g s t u d i e d

A l l cows w e r e f r e e o f t u b e r c u l o s i s ,

B a n g 's d i s e a s e

a n d s t r e p t o c o c c i c m a s t i t i s when p l a c e d o n e x p e r i m e n t a n d r e ­
m ained f r e e

of tu b ercu lo sis

and B a n g 's d i s e a s e

th ro u g h o u t the

p e r i o d o f t h e s t u d y * ■ T h e cows w e r e h o u s e d i n a g o o d b a r n w i t h
co n crete flo o rs

in m etal sta n c h io n s.

A s u f f i c i e n t number o f

windows p r o v i d e d a d e q u a t e l i g h t i n t h e b a r n .
T h e c o n t r o l cow w a s s e p a r a t e d f r o m t h e two e x p e r i m e n t a l
cows b y a t h r e e f o o t w i d e c o n c r e t e w a l k .

The b a r n was t h o r o u g h l y

c l e a n e d by - c h e m ic a l m ea n s a n d w h i t e w a s h e d a f t e r r e m o v a l o f one
grpup of a n im a ls and p r i o r t o b e in g u s e d f o r
The r o u t i n e
1.

s a n i t a r y m e a s u re s em ployed i n t h e b a rn w ere:

t o m i l k t h e c o n t r o l cow b e f o r e t h e two cows e x p o s e d t o t h e

strep to co ccu s,
to

th e second group.

the

at a ll

2 . t o rem ove m anure from and g i v e c l e a n b e d d in g

c o n t r o l cow f i r s t
tim es,

and 4 .

each tim e ,

3.

to keep th e b a rn c le a n

t o k e e p a f i l m o f l i m e on t h e r i o o r a t

a l l tim es.
As a l r e a d y i n d i c a t e d t w o cows w e r e e x p o s e d a n d t h e t h i r d
cow w a s t h e c o n t r o l .

The e x p o s u r e s and f r e q u e n c y o f e x p o s u r e s

i n a d d i t i o n to th e o r d e r o f e x p o su re s fo llo w :

(a)

Fed - f i v e

cu b ic

c e n tim e te rs of a 24-hour b ro th

c u l t u r e tw i c e d a i l y f o r one m onth.
( b ) S u b c u t a n e o u s - 10 c u b i c c e n t i m e t e r s
cu ltu re in je c te d at a p o in t

(c)

ju st p o ste rio r to

rj £ > m t

of the w ith e rs ,

m onth

( a t o t a l o f 12 i n j e c t i o n s ) .

th ree

of a 2 4 -h o u r b ro th

t i m e s a week f o r

the
one

I n t r a v e n o u s - 10 c u b i c c e n t i m e t e r s o f a 2 4 - h o u r b r o t h
c u l t u r e t h r e e t i m e s a w e e k f o r one m o n t h ( a t o t a l
o f 12 i n j e c t i o n s )

(d)

D ip t e a t s - i n t o

in to

the

ju g u la r v ein .

a 24-hour b ro th c u ltu r e th r e e tim es

a week f o r one m onth (a t o t a l o f 12 e x p o s u r e s ) .
(e)

In ju re

te a ts - la c era te

t o draw b lo o d )

t e a ts w ith s e a lp e l

th e n dip

o f 12 e x p o s u r e s ) .

by d ip p in g the t e a t s
strep to co cc u s
ro u tes.

t e a t s f o r one m o n th (a t o t a l

The f i r s t y e a r ,

o f t h e two cows e x p o s e d ,

(su fficien t

fo llo w in g i n f e c tio n

t h e c o n t r o l cow w a s e x p o s e d

w ithout p rev io u s exposure to th e

by t h e o r a l ,

su b c u ta n e o u s and i n tr a v e n o u s

D uring th e second y e a r th e n a t u r a l e x p o su re

i n th e b a rn r e s u l t e d i n i n f e c t i o n of th e
th erefo re

c o n t r o l cow,

sh e was n o t e x p e r i m e n t a l l y e x p o s e d .

The q u a n i t a t i v e d e t e r m i n a t i o n o f th e m ilk f o r p e r

cent of

c a s e i n n i t r o g e n a n d p e r c e n t o r whey p r o t e i n n i t r o g e n w e r e m a d e
fo llo w in g the

tech n ic

of Van S ly k e and B o sw o rth

(29).

The

K j e l d a h l - G u n n i n g m eth o d (1) was u s e d t o d e t e r m i n e t h e t o t a l
n itr o g e n co n ten t o f m ilk .
u n d ilu te d m ilk a t

its

whey b y f i l t r a t i o n .

T h e c a s e i n was p r e c i p i t a t e d

in the

i s o e l e c t r i c p o i n t and s e p a r a t e d from th e
An a l i q u o t p o r t i o n o f t h e f i l t r a t e w a s

a n a ly z e d ,

in d u p lic a te ,

r o r t h e p e r c e n t o r w hey n i t r o g e n .

The p e r c e n t o f c a s e i n n i t r o g e n was o b t a i n e d
su b tra ctin g

by d i f f e r e n c e ;

t h e w he y n i t r o g e n f r o m t h e t o t a l n i t r o g e n

co n ten t

o f th e m ilk .
The c u r d t e n s i o n o f t h e m i l k was d e te r m i n e d a c c o r d i n g t o
the te c h n ic
te st),

o f C ole ( 9 ) .

c o n t e n t , pH ( t h y b r o m o l

an d p e r c e n t c h l o r i d e s w ere d e te r m i n e d by t h e m e th o d s o f

Hucker (2 0 ).
p late

The le u c o c y t e

The m e th y le n e

b lue r e d u c tio n t e s t and s ta n d a r d

c o u n t w e r e m ad e a c c o r d i n g t o

A m erican P u b l i c H e a l th A s s o c ia t i o n

s ta n d a r d m ethods of t h e
(2).

The p r e s e n c e o r t h e

s t r e p t o c o c c u s was d e t e r m i n e d by t h e m i c r o s c o p i c t e s t
tech n ic
of the

(7).

The

o f U d a l l (28) was f o l l o w e d i n m a k in g p h y s i c a l e x a m i n a t i o n
udder.

B lo o d c e l l c o u n t s w e re made by f o l l o w i n g t h e t e c h n i c

of E olm er and B o e r n e r ( 2 2 ) .

A S a h l i h e m o g lo b in o m e te r was u s e d

f o r m aking h e m oglobin d e t e r m i n a t i o n s .
The h e m o g lo b in o m e te r t u b e was c a l i b r a t e d on t h e b a s i s o f
14 gram s o f h e m o g lo b i n p e r 100 c u b i c c e n t i m e t e r s o f b l o o d a s
100 p e r

c en t o f hem oglobin.

I n e a c h c a s e t h e a b o v e d e t e r m i n a t i o n s w ere made t h r e e
a week t h r o u g h o u t t h e e x p e r i m e n t .
w e r e m ade i n d u p l i c a t e .

tim es

The c h e m ic a l d e t e r m i n a t i o n s

A ll f i g u r e s w ere av erag ed to o b t a i n

the f ig u r e s p re s e n te d in th e T ab les.

I n m ost ca se s th e

o f t h e f i g u r e s a v e r a g e d was v e r y s m a ll ;

i n some c a s e s ,

spread
esp ecially

a fte r in fec tio n ,

t h e s p r e a d o f f i g u r e s a v e r a g e d was g r e a t e r .

On t h i s

the

acco u n t,

sp re a d o f such f i g u r e s

is

i n d i c a t e d by

g iv in g th e av erag e to g e t h e r w ith the o u te r l i m i t s
the f i g u r e s .

of sp re a d of

The t h r e e

cows o f t h e f i r s t

y e a r w ere s l a u g h t e r e d one t o

tw o a n d o n e - h a l f m o n t h s a f t e r i n f e c t i o n a n d t h e u d d e r s e x a m i n e d
i n g r o s s and h i s t o l o g i c a l l y .

The u d d e r was d i v i d e d i n t o p l a n e s

and q u a d ra n ts of each q u a r t e r f o r

convenience in re c o rd in g

lo c a tio n o f the p a th o lo g ic a l c o n d itio n s

the

o b s e r v e d o n g r o s s ex am ­

i n a t i o n and in i d e n t i f y i n g t i s s u e s rem oved f o r m ic r o s c o p ic
study.

P l a n e one r e f e r s t o

nearest

to t h e body o f th e

p a r t and p la n e t h r e e

the upper p a r t of th e udder or t h a t
cow, p l a n e t w o r e f e r s t o

th e m iddle

to th e low est p o r tio n o f the u d d e r.

The

q u a rte r s of the udder are

d e s i g n a t e d R .R . f o r r i g h t r e a r ,

for rig h t

for

left

a s view ed from b e h in d th e

cow.

f r o n t , L.F*

fro n t,

P t>
D D
k&

^

in Z e n k e r's

th e f o l l o w i n g schem e:

&

©

K JL *

c c

A

to a p a r t of th e r i g h t r e a r q u a rte r of

p l a n e o n e a n d q u a d r a n t B.
w ere f i x e d

rear

<= £ AS
R.T.
l.H

B
6

T h u s RR1B r e f e r s

for le f t

Im a g in a ry q u a d r a n t s were d e s ­

ig n a te d in each p lan e a cco rd in g to
r/K

and L .R .

R .P .

The t i s s u e s f o r m ic ro s c o p ic s tu d y

so lu tio n ,

embedded i n p a r a f f i n and

s t a i n e d by e o s i n and h e m a to x y lin .
R e s u lts and D isc u ssio n
1 . T he s t r e p t o c o c c u s e m p l o y e d i n t h i s

study - S trep to co ccu s

ag a la c tia e .
T h e s t r e p t o c o c c u s u s e d i n tlj&s s t u d y w a s i s o l a t e d f r o m a

ch ro n ic case of m a s titis
in ducing m a s ti t is
Its

t h r e e m onths p r i o r to

its

use in

and i d e n tif ie d as S trep to co ccu s a g a la c tia e .

ch aracteristics

c an b e s t be g i v e n a s s e a t e d by H an sen ( 1 6 ) .

" I t h a s b e e n c o n c l u d e d t h a t t h e p r e f e r a b l e na me f o r t h i s

strep ­

t o c o c c u s i s S t r e p . a g a l a c t i a e , L eh m an n a n d Newmann ( 1 8 9 6 ) .
m ost s i g n i f i c a n t
o th er

c h a r a c t e r i s t i c s w hich d i f f e r e n t i a t e

clo sely re la te d

d u c t i o n from m a l t o s e ,
t i o n from m a n n ito l,
in u lin ,
slip t

red u ctio n ,

from

acid p ro ­

s u c r o s e , and d e x t r i n w i t h no a c i d p r o d u c ­

so rb ito l,
It

arab in o se,

xy lo se,

raffin o se,

a t t a c k s sodium h i p p u r a t e ,

and produces e it h e r a v ir id a n s

ty p e o f hem olysis

on b lo o d a g a r p l a t e s .

It

does not

or narrow -zone

c u r d le s m ilk b e fo re

r e d u c t i o n p r o g r e s s i n g a f t e r w a r d s s lo w ly from th e

b o ttom u p w ard s."
agar.

s p e c ie s of s tr e p to c o c c i a re i t s

and a m y g d a lin .

e scu lin ,

it

Its

T his

c u l t u r e w a s o f t h e gamma t y p e o n b l o o d

These c h a r a c t e r i s t i c s

E n g leb rech t

(14)

a r e e s s e n t i a l l y t h o s e r e p o r t e d by

and W illiam s

(3b)

for S trep ,

ag alac tia e .

2 . The p o r t a l o f e n t r y o f t h e s t r e p t o c o c c u s i n t o

the u d d e r.

E x p o s u r e o f t h e e x p e r i m e n t a l cows w e r e m ad e u s i n g t h e a b o v e
organism .
in a ll

A l l cows w e r e a t

cases

the b e g in n in g of a l a c t a t i o n p e rio d ;

being e i t h e r i n t h e i r f i r s t

or second l a c t a t i o n

p erio d s.

T h e f i r s t m o n t h o f s t u d y was a c o n t r o l p e r i o d

exposure)

fo llo w ed

in

by e x p o s u r e s f o r o n e m o n t h p e r o s , f o l l o w e d

t u r n by s u b c u t a n e o u s ,

not yet in fec te d ,

in trav en o u s,

d ip p in g t e a t s

and i f

th e t e a t s w ere l a c e r a t e d and t h e n d ip p e d

i n t o a b r o th c u l t u r e of th e organism .
are p resen ted

(no

in T able I .

The r e s u l t s o f t h i s work

T able I .

The p o r t a l o f e n t r y o f th e s t r e p t o c o c c u s i n t o
c ows u d d e r a s i n d i c a t e d b y e i t h e r i n f e c t i o n
i n f e c t i o n f o llo w in g e x p e rim e n ta l exposure*

MONTH 0 5 STUDY
6
5
3
4
M ethod o f E x p o su re
In ju re
Kone F e d S u b c u In traDip
tan eo u s venous T e a ts T e a ts
2

1

COW
G 1935-36

-

-

-

-

H 1935-36

-

-

-

-

1 1936-37

-

-

-

-

2 1936-37

-

-

_

GH( c o n t r o l ) 1 9 3 5 - 3 6

0

0

0

1936-37

0

0

0

3 ( c o n tro l)
Legend:

1*

th e
or no

+ * in fectio n ,

—

7
Dip
T eats

+

0

0

0

+

0

0

+

0

0

0

0

0

+1

0

0+g

0

0

= no i n f e c t i o n ,

-

0 = no e x p e r i m e n t a l
exposures.

C o n tr o l o f 1935-36 rem ained n e g a tiv e th ro u g h o u t p e r i o d of
e x p o s u r e o f t h e two e x p e r i m e n t a l cow s, a f t e r t h e i r i n r e c t i o n
the

2.

c o n t r o l cow was e x p o s e d b y d i p p i n g t h e t e a t s ,

C o n t r o l o f 1 9 3 6 -3 7 became i n f e c t e d a s a r e s u l t o f e x p o s u r e t o
t h e s t r e p t o c o c c u s d u e t o b e i n g s t a b l e d i n t h e sa m e b a r n w i t h
t h e e x p e r i m e n t a l cows.
T h r e e o f t h e e x p o s e d a n i m a l s (H, 1 a n d 2)

co ccic m a s t i t i s
In fec tio n

as a r e s u l t of d ipping the t e a t s

in to

the

c u ltu re.

f o l l o w e d s e v e n t o n i n e e x p e r i m e n t a l e x p o s u r e s m ad e t h r e e

tim e s a week.
only a f t e r

developed s t r e p t o ­

One o t h e r

d ip p in g o f the

cow (G) d e v e l o p e d s t r e p t o c o c c i c m a s t i t i s
lac era te d

te a ts.

In th is

case in f e c tio n

f o l l o w e d one e x p o s u r e .

T h is i n d i c a t e s t h e p a r t p l a y e d by

in ju ries

o f th e u d d e r on t e a t s i n t h e

m astitis

and th e n e c e s s ity

These r e s u l t s
i n w hich m a s t i t i s

spread of stre p to c o c c ic

f o r p ro p e r ly c a rin g r o r such i n j u r i e s .

c o n f ir m t h e work o r K i t t

k itt

(1 0 ), M aass

and M aass (23)

c o u l d n o t b e p r o d u c e d by i n o c u l a t i o n p e r o s

o r t h e s u b c u ta n e o u s and i n t r a v e n o u s r o u t e s
an im als,

(21)

(21), R o sell

(26),

Edw ards,( 1 3 ) ,

(23) and H a d ley and F r o s t

co ccic m a s t i t i s by in tr o d u c in g th e
can al or in to the u d d er.

It

is

in to

ex p erim en tal
D av is and Capps

(15) p ro d u c e d s t r e p t o ­

stre p to c o cc u s in to the te a t

sig n ific an t,

c o n c e rn in g the

r e s u lts here rep o rte d ,

t h a t th e e x p o su re of th e u n i n j u r e d and th e

in ju re d te a ts re s u lte d

in in fe c tio n ,

t u n i t i e s in the r o u tin e

t h e r e a r e m any o p p o r ­

s t a b l i n g a n d h a n d l i n g o f cows f o r

c o n ta m in a tio n s and i n j u r i e s
3.

for

such,

to occur.

The c o n t r o l o f s t r e p t o c o c c i c m a s t i t i s

by s a n i t a r y m e a s u r e s

and s e g r e g a t i o n of i n f e c t e d cows.
A fter the

two e x p e r i m e n t a l cows w e r e i n f e c t e d ,

w hich s e rv e d a s a c o n t r o l

cow d u r i n g t h e f i r s t y e a r , w a s

exposed t o t h e s t r e p to c o c c u s by d ip p in g th e t e a t s
cu ltu re,

cow G-E,

in to the

a n d became i n f e c t e d f o l l o w i n g t h r e e s u c h e x p o s u r e s .

The f a c t t h a t t h e

c o n t r o l cow (G) o f t h e 1 9 3 5 - 3 6 p e r i o d w a s

p r o t e c t e d from th e s t r e p t o c o c c i c m a s t i t i s p r e s e n t i n th e h e rd
by t h e p u r s u a n c e o f s a n i t a r y p r o c e d u r e s seems s i g n i f i c a n t .
T h e d a t a o n T a b l e I sh ow t h a t
perio d ,

cow 3 ,

c o n t r o l cow f o r

th e 1926-37

became i n f e c t e d Y /ith o u t e x p e r i m e n t a l e x p o s u r e e v e n

th o u g h s a n i t a r y p r o c e d u r e s w ere r o u t i n e l y em ployed t o p r e v e n t

th e spread or stre p to c o c c ic m a s titis .
the

d iffic u lty

th e

in fec te d

of c o n t r o l l i n g the

These r e s u l t s

in d icate

i n f e c t i o n by s e g r e g a tio n o f

cow s a p a r t f r o m t h e n e g a t i v e cows i n t h e sa me

b a m a n d t h e employment o f s a n i t a r y p r o c e d u r e s I n h a n d l i n g
the d a i r y h e rd .
the

freedom of i n f e c t i o n of the

p erio d p rio r
4•

That th e y a r e of v a lu e i s

c o n t r o l cow o f - t h e 1 9 3 5 - 3 6

t o h e r e x p o s u r e by d i p p i n g o f t h e t e a t s .

The v a r i a t i o n

in c o m p o sitio n of m ilk f o llo w in g i n f e c t i o n .

The p r e s e n c e o f m a s t i t i s
n o t a norm al c o n d itio n ,
in th e

d e m o n s t r a t e d by

strep to co cci

t h e r e f o r e one m ig h t

com position of m ilk as a r e s u l t

th e norm al f u n c t i o n of th e u d d e r.
n i t r o g e n , whey n i t r o g e n ,

expect v a ria tio n s

of i n t e r f e r e n c e w i t h

The d a ta of th e

and cu rd t e n s i o n ,

pH a n d p e r c e n t o f c h l o r i d e s p r i o r

w ere n o rm al, w ith s l i g h t v a r i a t i o n s ,

le u c o c y te co u n t,

In each case th e se v a lu e s
p r io r to in fe c tio n .

c u rd t e n s i o n d e c r e a s e d from i t s

in d ic atin g a so ft

H i l l f s (18)

c u rd and more

t h a n 30 g r a m s a h a r d c u r d w a s u s e d t o c l a s s i f y
c h a ra c te r of th e m ilk .

At th e

norm al v a lu e

t o a p o i n t w h e r e f r e q u e n t l y no c u r d was f o r m e d .
s t a n d a r d 30 g r a m s o r l e s s

the

curd

The c u r d c h a r a c t e r was f a i r l y u n i f o r m

du rin g th e p e rio d p r i o r to

strep to co ccu s in f e c tio n ,

and a g r e e s

w i t h t h e r e s u l t s r e p o r t e d by B e r ry (4) and B i d e l l e t a l .
W eisberg e t a l .

In.

t h e whey n i t r o g e n i n c r e a s e d

and t h e c a s e i n n i t r o g e n d e c r e a s e d a f t e r i n f e c t i o n .
same t i m e t h e

casein

to and a f t e r i n f e c t i o n of

e a c h cow a r e p r e s e n t e d i n T a b l e 2 .

fo u r of th e s ix an im als s tu d ie d ,

i n the u d d e r i s

(30) r e p o r t t h a t

(25).

t h e c o n c e n t r a t i o n o f whey

c o n s t itu e n t s w holly or s e p a r a te ly e x h ib i ts l i t t l e
in flu en ce
m ilk .

in d iffe re n tia tin g a so ft

o r no

c u rd from a h a rd c u rd

They d i d f i n d t h a t a h i g h c o n c e n t r a t i o n of

c a s e i n was

a s s o c i a t e d w i t h a h a r d c u r d m i l k a n d a lo w c o n c e n t r a t i o n w i t h
soft

curd m ilk .

D o a n a n d Y/elch ( 1 2 )

shOY/ed t h a t

the

curd

t e n s i o n v a lu e s o f m ilk from i n f e c t e d u d d e rs a re lo w e r,
p ared w ith the case in
a n d Doan ( 3 1 )

co n ten t,

th a n a norm al m ilk .

sum m arize t h e i r work t h u s — " s o f t

com­

W elch

curd i s not

e v i d e n c e t h a t m i l k comes fro m a n u d d e r sh o w in g d i s e a s e b u t u d d e r
in fectio n s
casein

do c a u s e a l o w e r i n g o f c u r d t e n s i o n d u e t o a l o w e r

co n te n t."

The d a ta o f T ab le 2 i n d i c a t e t h a t th e

decrease

i n h a r d n e s s of c u rd from i t s norm al v a l u e i n each c a s e d e v e lo p e d
c o in c id e n t w ith a d e c re a se in c a s e in n itr o g e n and an in c r e a s e
i n whey n i t r o g e n .
The p H ,c h lo r id e

co n ten t,

and l e u c o c y t e

p r o d u c e d b y t h e cows a f t e r i n f e c t i o n v a r i e d
tim e to tim e ; n o t a l l

of th ese

co n ten t of the m ilk
c o n s id e r a b le from

c o n d it i o n s w ere abnorm al a t any

one tim e u n l e s s t h e m i l k was f l a k y o r g a r g e t y .

Some o f t h e s e

t e s t r e a c t i o n s were a b n o rm a l c o n t i n u o u s l y a f t e r i n f e c t i o n by
the

strep to co ccu s.

resu lts

f r o m cow t o

d ifferen t

cows,

On a c c o u n t o f t h e v a r i a t i o n o f t h e s e

test

cow o r f r o m t i m e t o t i m e o n t h e sa m e o r

t h e pH,

c h lo r id e and le u c o c y te

co n ten ts of th e

m ilk can n o t a lo n e be used a c c u r a t e l y to d e te c t c a se s of
strep to co ccic m a s titis .

- 13 -

T ab le 2 *

The c o m p o sitio n o f m ilk p r i o r to i n f e c t io n and a f t e r i n f e c t i o n f o r each
one o f th e s i x cows o f th e e x p e rim e n t.

Month o f Study
1

2

U

3

.5

.. .

6

7

Cow G
P r i o r to I n f e c t io n
P e rc e n t o f c a s e in I 0 . 1+3
P e rc e n t o f whey & 0 .1 0 5
Card te n s io n
1+04-10
L eucocyte c o n te n t
50T
pH
6. 2
0.11+
P e rc e n t c h lo r id e s

0.1+1+
0 .1 1
U5+S
S5T
6 .6
0.11+

A f te r I n f e c t i o n
0.UU5
0 ,1 1
UO+lU
70T
6 .6
0.1U

.0.1+1+
0 .1 1
1+8+11
70T
6 .7
o .iU

0.U3
0 .1 1
32+12
75T
6 .6
0.1U

0.U1
0 .1 1 2
U^-10
100T+30T
6 .6
o .iU

0 .3 6
O .lgj-p.07
20+20
UOMi- UOM
7*3
0 .1 9

Cow H
P r i o r to I n f e c t io n
P e rc e n t o f c a se in IT
P e rc e n t o f whey IT
Card te n s io n
L eucocyte c o n te n t
PH
P e rc e n t c h lo r id e s

0 .3 1
0 .0 9

0 .3 2
0 .0 s

28+5

32+ 10

100T
6* 6
0.11+

100T
6 .7
0.11+

A fte r In fe c tio n
0 .3 2
0 .0 8
2U+12
100T
6-7
o .iU

0 .3 3
.079
30+8
60T
6 .7
O.lU

O.32
0.0 8
20+12
6Ut
6 .7
O.15

0*33
0 .0 8
28+10
75T
6 .6
0 .1 5

0 .3 0 * 0 .OU
O.lOf-O.02
10+20
5M+Um
7 * i+ 2 .0
0 .1 8

Cow I
P r i o r to I n f e c tio n
0 .388
0.1+0
P e r c e n t o f c a s e in 13 O.3S
0 .1 0
0 .1 0 5
P e rc e n t o f whey IT 0 *09*5
35+10
Card te n s io n
kO+15
U8+I2
HOT
L eucocyte c o n te n t
70T
100T
6 .6
pH
6 .6
6 .7
0.1U
o .iU
O.lU
P e rc e n t c h lo r id e s

0.U0
0 .1 0
U5+9
6o t
6 .7
0.1U

A fte r In fe c tio n
0.U0
O.3S
O.36
0.1 1
0.1 1 5
0 .1 1
32+10
30+12
36+7
10M+10M SM+ 3M Ul + UM
6 .9
6 .7
7 .1
0 .1 9
0. 1 8 .
0 .1 8

Cow 2
P r i o r to I n f e c tio n
“ 0 .3 2 *
O.3O5
P e rc e n t o f c a s e in IT O .3I
0 .1 0
0 .0 9
P e rc e n t o f whey IT 0 .1 0
2 8+8
35+10
28+5
Curd te n s io n
70T
100T
95T
L eucocyte c o n te n t
6 .6
6 ;6
pH
6 .7
0.1U
O.lU
0.11+
P e rc e n t c h lo r id e s

A f te r I n f e c ti o n
tmr Wh.

■ UM T T i f

0.1 0
32+12
130T
6 .6
O.lU

0.1 1
18+12
2M+2M
6.9
0 .1 7

0730”
0.116
3+13

~o”.
.0 .1 1
12+10

S00T+600T 200T
6 .7
6 .6
0 .1 6
O.15

- 1U T able 2 (c o n tin u e d )

Cow G-H
P r i o r to i n f e c t i o n
P e r c e n t o f c a s e in IT
P e r c e n t o f whey IT
Curd te n s io n
L eucocyte c o n te n t
pH
P e rc e n t c h lo r id e s

O.3 2
0 . 1.0

0*35

25*8
60T
6*7
O.lU

30+12
SOT
6 .7

0 .1 0 5

0 .1 5

0*33
0 .1 0
30 +s

120T
6 .6
O.lU

A f te r
I n f e c tio n
0 .3 2
0 .1 0
33±>

0.315
0 .1 0 2

2S+11

100T

85 T

6 .6
0 .1 5

0 .1 5

6.7

O.3 2
O.IO 3
33+15
120T

O.3 O
0 .0 9
16+17
2M+2M

6 .6
0 .1 5

0 .1 5

6 ,7

Cow 3
P r i o r to i n f e c t i o n
P e r c e n t o f c a s e in IT
P e rc e n t o f whey IT
Curd te n s io n
L eucocyte c o n te n t
pH
P e r c e n t c h lo r id e s

o.Uo
0.105
35+10
100T

0.39
0 . 10 s
2S+15
70T

6 .6

6 .6

O.lU

O.lU

0*395

0 .1 1
30+10

120T
6 .7
o.iU

A fte r In fe c tio n

O.3 8 8
0 .1 1

39+16
SOT
6 .6

O.lU

O.3 S
0.118
20 +1 S
6M+5M
7,U
0.19

0.37
0 .1 2
5+10
UMf2M

7*2

0 .2 0

0 . 3s
0 . 11 U
20+12
5mTUm

7*o
0 . 1s

5.

The r e d u c t i o n i n t h e q u a l i t y o r m ilk p ro d u c e d by i n f e c t e d
cows.
The c h e m ic a l and c e l l u l a r

c o m p o s i t i o n o f m i l k a r e imp­

o r t a n t b e ca u se th e y i n f l u e n c e th e b a c t e r i o l o g i c a l q u a l i t y and th e
f l a v o r an d odor w hich a r e i m p o r t a n t from th e
p o in t.

The s t a n d a r d p l a t e

consum er*s s t a n d ­

c o u n t o f t h e m i l k f r o m e a c h cow w a s

low p r i o r t o i n f e c t i o n a s i n d i c a t e d b y t h e d a t a o f T a b le 3;
e a c h c a s e w i t h i n from one t o t h r e e m o n th s a f t e r
count in c r e a s e d to w e ll over 1000.
a b ility
d u ctio n .

of h av in g m a s t i t i s f r e e

in fectio n

cow s f o r h i g h q u a l i t y m i l k p r o ­

during t h is

one i n e a c h

tim e th e le u c o c y te c o n te n t

o f t h e m i l k was l e s s t h a n a n a v e r a g e o f 1 3 0 ,0 0 0 p e r c u b ic
m eter.

the

T his d e m o n stra te s th e d e s i r ­

The m e t h y l e n e b l u e t e s t r a t i n g was c l a s s

case p r io r to in f e c tio n ;

in

cen ti­

F o l l o w i n g i n f e c t i o n f o u r o f t h e cows e x h i b i t e d a p o o r

m ethylene b lu e t e s t r a t i n g

(class

2 , 3 o r 4) and a t th e

same

tim e had an i n c r e a s e d le u c o c y te c o n te n t o f th e m ilk ra n g in g
from 2 ,0 0 0 ,0 0 0 to 8 ,0 0 0 ,0 0 0 p e r

cubic c e n tim e te r .

An i n c r e a s e

i n l e u c o c y t e c o n t e n t h a s b e en fo u n d to be r e s p o n s i b l e f o r t h e
r e d u c tio n of the m ethylene b lu e,

th e re b y causing such m ilk to

be c l a s s e d a s tw o,

(11).

th re e or fo u r

the d e c re a se in q u a lity of m ilk ,
p late

I n two o f t h e s i x

cows

a s m easu red by th e s t a n d a r d

c o u n t and m e th y le n e b l u e r e d u c t i o n t e s t , d i d n o t o c c u r

u n t i l from one to

t h r e e m o n th s a f t e r i n f e c t i o n by t h e

t o c o c c u s w h i l e t h e o t h e r f o u r cows e x h i b i t e d t h e
q u a l i t y w i t h i n t h e f i r s t m onth.

T herefore,

strep ­

decrease

in

a cow w i t h s t r e p ­

to c o c c ic m a s t i t i s w i l l pro d u ce m ilk of a low er q u a l i t y as

- 16 T ab le 3 *

The Q u a lity o f M ilk Produced by Cows b e f o r e and a f t e r I n f e c t i o n .

Month o f Study
1

2

3

^

5

6

7

Cow G
S ta n d a rd p l a t e count
Meth. b l u e c l a s s
L eucocyte c o n t e n t

100
1
50T

P r i o r to I n f e c t i o n
150
150
1
1
. S5T
70T

150
1
70T

A fte r In fectio n
150
1200*1+00
1
3
IOOT+3OT UOM+l+OM

200
1
75T

Cow H
A fte r In fe c tio n

P r i o r to I n f e c t i o n
S ta n d a rd p l a t e count
Meth. b l u e c l a s s
Leucocyte c o n t e n t

110
1
100T

125
1
100T

100
1
60T

150
1
6Ut

150
1
100T

150
1
75T

5000*1000
3
5M+1+M

Cow I
A fte r In fectio n

P r i o r to I n f e c t i o n
CVI

200
1
100T

0r-o

S ta n d a rd p l a t e count
Meth. b lu e c l a s s
Leucocyte c o n t e n t

1
70T

200
1
HOT

300
1
60T

2000+1700 22OO+5OO 2800*200
k
3
3
10M+10M
8M+3M
Ulfrl+M

Cow 2
S ta n d a rd p l a t e co un t
Meth. b lu e c l a s s
L eucocyte c o n t e n t

P r i o r to I n f e c t i o n
200
280
150
1
1
1
70T
100T
95T

A fte r In fe c tio n
280
1
130T

1+00
3
2M*2M

3000+1000 2800+600
2
2
S00T+600T
200T

Cow GH
P r i o r to I n f e c t i o n
S ta n d a r d p l a t e count
Meth. b lu e c l a s s
L eucocyte c o n te n t

100
1
60 T

150
1
SOT

170
1
120T

150
1
100T

150
1
S5T

100
1
120T

. A fte r
In fectio n
900+200
2
2M*2M

Cow 3
S ta n d a r d p l a t e count
Meth. b l u e c l a s s
L eu co cyte c o n te n t

P r i o r to I n f e c t i o n
3OO
200
250
1
1
1
120T
70T
100T

200
1
SOT

A fte r In fe c tio n
S5O+2OO 1S00+U00 2OOO+ISO
2
2
3
6i%5M
l+M+21!
5%kH

m easured by th e above t e s t s
a te ly fo llo w
b•

a n d t h e d e c r e a s e may n o t i m m e d i ­

i n f e c t i o n by th e s tr e p to c o c c u s .

The v a l u e o f t h e v a r i o u s

tests

in the d e te c tio n of e x p e r i­

m e n ta lly induced s tr e p to c o c c ic m a s t i t i s .
The v a r i a t i o n s

in the

c o m p o s itio n o f m ilk r e s u l t i n g from

i n f e c ti o n have been u t i l i z e d as th e b a sis of th e in d ir e c t t e s t s
for m a stitis.

S im ilar v a ria tio n s

c o n t e n t , pH ( t h y b r o m o l t e s t )

in leu co cy te

b eg inning or the

t h e cows r e m a i n i n g n e g a t i v e t o

m i c r o s c o p i c t e s t a n d g i v i n g no e v id e n c e o f m a s t i t i s
e x am in atio n of th e u d d e r.

ch lo rid e

and p h y s ic a l ap p earan ce have been

n o t e d i n t h e m i l k o f n o r m a l cow s n e a r t h e
of th e l a c t a t i o n p e rio d ,

co n ten t,

Such v a r i a t i o n s

cows m a k e d i f f i c u l t t h e i n t e r p r e t a t i o n

end

the

on p h y s i c a l

I n th e m ilk o f norm al

of the i n d i r e c t

tests

for m a s titis .
The d a t a of T a b l e 4 p r e s e n t t h e r e s u l t s
tests

em ployed,

i.e .

or th e v a r i o u s

the d i r e c t te s t-m ic ro s c o p ic ,

in d ire ct te s ts

l e u c o c y t e a n d c h l o r i d e c o n t e n t , pH a n d t h e p h y s i c a l a p p e a r a n c e
o f th e m ilk and th e p h y s i c a l e x a m in a tio n of th e udder o r each
cow f o l l o w i n g i n f e c t i o n .
n eg ativ e
The f i r s t

or norm al p r i o r

In a ll

to i n f e c t i o n by th e s t r e p to c o c c u s .

e v i d e n c e o f i n f e c t i o n was a p o s i t i v e m i c r o s c o p i c

w hich d e t e c t e d th e p r e s e n c e
cows o f t h i s

of the s tr e p to c o c c u s .

study d e te c ta b le

scar tissu e

f i r s t m onth o f i n f e c t i o n i n t h r e e
in

c a s e s th e t e s t r e s u l t s w ere

th e rem ain in g th r e e

order of e ffic ie n c y

cows.

te st,

In the s ix

developed d u rin g the

cows a n d i n t h e s e c o n d m o n t h

T h ese were f o l lo w e d i n d e c r e a s i n g

in d e te c tin g

s t r e p t o c o c c i c m a s t i t i s by th e

T able 4.

The e f f i c i e n c y o f t h e v a r i o u s t e s t s i n
d e te c tin g ex perim ental stre p to c o c c ic
m a s t i t i s i n s i x cows.

M onths r o l l o w i n g i n f e c t i o n when t e s t
r e a c t i o n became p o s i t i v e
N o t i n 2*

E xam ination

1

2

M icro sco p ic t e s t

6

0

0

P h y s i c a l exam o r u d d e r

3

3

0

L eucocyte

4

1

1

3

1

2

3

1

2

2

0

4

co n ten t

C h lo rid e co n ten t
;

Thybrom ol t e s t

(pH)

P h y s i c a l exam o f m i l k
*The cows w e r e e i t h e r
d isco n tin u ed a f t e r

s l a u g h t e r e d o r s t u d y o n t h e m was
t h e two m o n th s p e r i o d .

leu co cy te

c o n ten t,

c h lo rid e

co n ten t,

p h y s ic a l ap p ea ra n c e of th e m ilk .

thybrom ol

(pH) a n d t h e

The m i c r o s c o p i c t e s t a n d

"k*10 p h y s i c a l e x a m i n a t i o n o f t h e u d d e r a r e o f g r e a t e s t v a l u e
in the

e a rly d ete ctio n of strep to co ccic m a s titis ,

re su lts
w hile

of th ese

the r e s u l t s

or p o s itiv e
7•

two t e s t s
o f the

from tim e

rem ain c o n sta n t a f t e r

in d ire ct

and th e
in fectio n

t e s t s v a r y , b etw een n e g a tiv e

to tim e.

The c e l l u l a r and h e m o g lo b in c o n te n t o f bov in e b l o o d .
E r y t h r o c y t e and l e u c o c y t e

c o u n t s w e r e m ade a c c o r d i n g

th e m ethods l i s t e d

by K olm er and B o e rn e r

from each a n im a l.

B l o o d s m e a r s w e r e made on c o v e r g l a s s a n d

s ta in e d w ith H astin g s

stain

(22)

to

on c i t r a t e d b l o o d

fo r d i f f e r e n t i a l leu co cy te

co u n ts.

The c o u n t s d i d n o t v a r y s i g n i f i c a n t l y

from tim e t o tim e o r

du ring the d i f f e r e n t

strep to co ccu s.

exposures to the

c o u n t s a r e p r e s e n t e d i n T a b l e 5 f o r e a c h o ne o f t h e

T y p ical
six

cows.

T h e se n o rm a l c o u n ts a g r e e w i t h t h o s e r e p o r t e d by H ayden a n d
E is h (17)

a n d Hol m ( 1 9 ) .

by t h e s e i n v e s t i g a t o r s ,
b asis

H e m o g l o b i n d e t e r m i n a t i o n s , w e r e m ade
u s i n g th e T a l l q u i s t m ethod;

on t h i s

t h e y f o u n d f r o m 75 t o 92 p e r c e n t o f h e m o g l o b i n i n

blood.

The S a h l i h e m o g lo b in o m e te r was u s e d t o

b in co n ten t

of th e blood i n

th is

in v estig atio n ;

cow ’ s

d e te rm in e hem oglo­
t h e a m o u n t was

l o w e r a s i n d i c a t e d by a n a v e r a g e o f f r o m 1 0 . 2 5 t o 1 0 . 5 g r a m s
p e r 100 c u b i c
as

c e n t i m e t e r s o f b l o o d a n d f r o m 73 t o 75 p e r c e n t

com pared w i t h

Holm*

The d a ta

th e v a l u e s r e p o r t e d by Hayden and E i s h ,
confirm

t h e w o r k o f Holm t h a t b o v i n e b l o o d

r e m a i n s u n a l t e r e d by m a s t i t i s
in d ic ate

and

i n f e c t i o n and i n a d d it i o n

t h a t e x p e r i m e n t a l e x p o s u r e s do n o t

sig n ific an tly a lte r

PO

o
p
o

o
c+
CO
w

^<1
»P
P*
o
o
ci
CD
at

2
CD
P
ct
hi
o
P*
MH
CD
CO

CD
ct
P
O'
P
CD
P
ct
P
O
13*
HH
CD
03

tn
p
&
o
>d
P1
H>
M
CD
01

td
o
03
H*
P
O
>P
P
H*
J-*
CD
CD

h+

C
D

H

lr*
0

P
o
o
o

0

p

ct
H-

P

ct
0
03

(—
*

td
ct

p*
t-j
O

a

ct
0
0

1
©
hi
o

P

•

Table

Grams hemoglobin per
100 C.o. of blood

fcl
H
»-b

.

3
B
•

5.

CD

to
to

on

03
o

O

ro

Q

N*

O

o
o

10.25(75$)

Oo

«•
CD

03

CJi

-o

03!

«03
•
Qi
O

ro

o

o

10.5(75$)

CO

CJi
to

co

CD

cn

co

03

O
o

O
O
«+
o
o
o

o>
o
O'

o
«•
o
o
o

H

cq

cn
Vft

10.5(75$)

CJ

to
on
00

10.25(7$$)

03

C
JI
to

03
H

C
O
00

C
JI

03

ro

03

C
O

03

C
O

o
o
o

cn
«*
or
o
C
D o
w
03 o
O o
o
o
cn
«a
03
O
00 o
S
*
o
8
8

to

Q
frl

03

before

10.25(72$)

on
03

to
<»

o
o
o
o
o

o
o

c e l l u l a r and hemoglobin content of the blood
and a f t e r i n f e c t i o n (no marked v a r i a t i o n ) .

U1
-O

o
o

The

10.5(75$)

Cn
03

21.

Its

c e l l u l a r and hem oglobin c o n te n t.

Q*

-Q.r Q s s p a t h o l o g y a n d h i s t o p a t h o l o g y o f t h e u d d e r s .
O ro ss e x a m in a tio n s and h i s t o p a t h o l o g i c a l s t u d i e s were

made o r t h e u d d e r s o f t h e t h r e e cows u s e d i n t h e e x p e r i m e n t
i n 1930-36.
h o lstein )
free

T h e y a r e d e s i g n a t e d a s G ( g u r n s e y ) , GH ( g u r n s e y -

and H ( H o ls te in ) •

or tu b e r c u lo s is ,

A ll th re e

lac ta tin g

cow s w e r e

B a n g 's d i s e a s e and s t r e p t o c o c c i c m a s t i t i s

when p l a c e d on e x p e r i m e n t , and r e m a i n e d f r e e o f t h e f i r s t
d is e a s e s th ro u g h o u t t h i s

stu dy.

tw o

They w ere or a g e t h r e e and

o n e -h a lf to fo u r and o n e -h a lf y e a r s .

The e x p e r i m e n t was c o n ­

d u c te d d u r in g th e f i r s t l a c t a t i o n p e r i o d of G and d u r in g th e
s e c o n d l a c t a t i o n p e r i o d o f cows GH a n d H .
slau g h tered

T h e cows w e r e

t h r e e ho u rs a f t e r b e in g m ilk ed i n th e se v e n th

m onth of t h e i r l a c t a t i o n p e r i o d .

The u d d e r s w ere ex am in ed i n

g r o s s and m a t e r i a l s rem oved and p l a c e d i n t o Z e n k e r 's s o l u t i o n
w ith in th re e hours a f t e r

slau g h ter.

Cow G G r o s s e x a m i n a t i o n - T h e l e f t h a l f m e a s u r e s 3 b . b c e n t i m e t e r s
an tero p o sterio rly ,

1 2 . b c e n t i m e t e r s m e d i o - l a t e r a l l y a n d 20*3

cen tim eters d o rs o -v e n tra lly .
th e t is s u e

o f L R 2 D and C i s

of L F 2 A and B i n d i c a t e s
parenchym a.
tissu e

is

Upon i n c i s i o n i n t o

the th re e p lan es

flesh y or f ib ro tic .

The a p p e a r a n c e

the p re s e n c e or v ery l i t t l e

In th e t h i r d p lan e th e in te r lo b u la r

fu n ctio n al

co n n ectiv e

v e ry prom inent.

The r i g h t h a l f m e a s u r e s 3 b . b c e n t i m e t e r s a n t e r o - p o s t e r i o r l y ,
11 c e n t i m e t e r s m e d i o - l a t e r a l l y a n d 2 0 . 3 c e n t i m e t e r s d o r s o - v e n t r a l l y
Upon c u t t i n g ,

the

The i n t e r l o b u l a r

s e c r e t i o n t h a t exudes i s

l i k e a w atery m ilk .

s e p ta a r e u n ifo rm ly p rom inent i n a l l p la n e s o f

22.

th e B B and B F q u a rte rs*
R F 1 B in d icate

The a p p e a r a n c e o r B B 2 B and

the p resen ce of e it h e r

c o n sid e ra b le f a t or

p r o d u c ts o f ex udation*
M icro sco p ic f in d in g s - In th e f i r s t p la n e ;
fu n ctio n al,
tio n *

t h e r e a r e m any r o c i

though m o stly

or p olym orphonuclear i n f i l t r a ­

A lso t h e r e a r e num erous m o n o n u clear l e u c o c y t e s i n th e

i n t e r s t i t i a l tissu e*
n u clear

T h e r e a r e m an y a r e a s s h o w i n g p o l y m o r p h o ­

ex u d atio n in to

p laces.

the a lv e o li

M oderate f i b r o s i s i s

th is plane

on t h e l e f t

com pletely r i l l i n g

ev id en t,

them i n

w i t h g r e a t e s t amount i n

side*

The se c o n d a n d t h i r d p l a n e s a r e l a r g e l y n o n - f u n c t i o n a l and
c o n t a i n m arked p r o d u c t i v e c h a n g e s.
l o b u l a r and i n t r a l o b u l a r

M arked f i b r o s i s

co n n ectiv e t i s s u e

is

The f o c i
two a n d

ex u d ate, p olym orp hon uclear,

show ing e x u d a t i v e

changes

are

in te r­

u niform ly d i s t r ib u t e d .

T h e re a r e num erous s m a ll f o c i o f a c u t e i n f e c t i o n
by f i b r i n o u s

of the

ch aracterized

and lym p h o cy tic re s p o n s e .
v e r y num erousi n p l a n e s

th re e of the r i g h t sid e .

Cow OH

G-ross e x a m i n a t i o n - T h e l e f t h a l f m e a s u r e s 3 3

cen tim eters a n te ro p o s te rio rly ,

1 2.1 c e n tim e te rs m e d io - la te r a lly

a n d 24*1 c e n t i m e t e r s d o r s o - v e n t r a l l y ,
q u a rte r in p lane

q u a d ra n ts A and C of L F

one h a v e p r o m i n e n t i n t e r l o b u l a r

sep ta.

In the

se co n d p l a n e a r e a s of n o n - f u n c t i o n a l parenchym a a r e e v id e n t*
The c h a n g e s a r e p r o g r e s s i v e l y m ore p r o n o u n c e d i n t h e t h i r d p l a n e ;
here

the lo b u le s a re

very l i t t l e

s m a l l ,i n t e r l o b u l a r se p ta p ro m in en t,

norm al f u n c t i o n a l parenchym a a r e fo u n d .

and

r i g h t h a l f m easures 3 3 .3 c e n tim e te rs a n t e r o - p o s t e r i o r ly*

cen tim e te rs m e d io -la te ra lly ,

v e n tra lly .

The s e c r e t i o n t h a t d r a i n s o u t upon c u t t i n g i n t o

th e udder is
a ll

norm al in a p p e a ra n c e .

The i n t e r l o b u l a r s e p t a o r

q u a d r a n ts i n th e f i r s t p la n e a r e p ro m in e n t, parenchym a

a p p a r e n t ly norm al,
a p p e a r norm al b u t
changes i n
the

a n d 25 c e n t i m e t e r s d o r s o -

in the
give

seco n d p l a n e v e r y few, i f

any, lo b u le s

th e a p p e a ra n c e of m arked e x u d a tio n .

The

t h e t h i r d p l a n e do n o t d i f f e r f r o m t h o s e n o t e d i n

second p la n e .
GH - M i c r o s c o p i c f i n d i n g s - I n t h e f i r s t p l a n e a r e a f e w

scattered foci
i s a lso

of e x u d a tio n of poly m o rp h o n u clear c e l l s .

in filtra tio n

or i n t e r s t i t i a l

l e u c o c y t e s and ly m p h o c y tes.

There

t i s s u e by p o ly m o rp h o n u c le a r

Ho d e g e n e r a t i v e c h a n g e s o f t h e

parenchym a a re e v i d e n t .
As n o t e d o n g r o s s e x a m i n a t i o n ,
i v e l y m ore p ro n o u n c e d i n
lo b u les

the

changes a re p r o g r e s s ­

th e second and t h i r d p l a n e s .

I n m any

o n e -h a ir o f th e a l v e o l i a re in v o lv e d i n a c u te exudate

p ro c e s s e s w hile th e o th e r o n e -h a lf of the a lv e o li a re not y e t
in v o lv ed .

Many o f t h e a l v e o l i a r e

The f o c i o f i n t e r s t i t i a l

s m a ll and a p p a r e n t l y i n a c t i v e .

in filtra tio n

and e x u d a t i o n o f p o l y ­

m o r p h o n u c le a r l e u c o c y t e s a r e m ore num erous i n th e

second p la n e

w i t h g r e a t e s t number o f i n v o l v e d a r e a s i n p l a n e t h r e e .
t o m arked f i b r o s i s

is p resen t.

Cow GH - G r o s s e x a m i n a t i o n - T h e l e f t
cen tim eters

M oderate

h a l f m easu res 3 2.5

a n t e r o l a t e r a l l y , 1 2 . & cen tim eters m e d io - la te r a lly ,

a n d 2 3 * 7 c e n t i m e t e r s d o r s o —v e n t r a l l y .

Upon i n c i s i o n i n t o

th e l e f t

h a lf an a b sc e ss about the s iz e of a h a ze l n u t i s

found a t

th e base of th e L F te a t*

Xn L R 3 D i s

found a

y e l l o w i s h g r a y f i l m homogenous a r e a a b o u t 6 m i l l i m e t e r s i n
diam eter.

There is

en cap su latio n .

ev id en ce of n e c r o s is ,

V ery l i t t l e

b u t no d i s t i n c t

ap p aren tly fu n c tio n a l tis s u e

found in any p la n e of e i t h e r f r o n t o r r e a r q u a r te r s .
in te rlo b u la r
is

is

The

s e p ta a re v e ry prom inent and th e g la n d u la r t i s s u e

d isco lo red .

The l e f t

s u p r a mammary l y m p h n o d e i s h y p e r e m i c

o r edem atous.
The r i g h t h a l f - m e a s u r e s 34 c e n t i m e t e r s a n t e r o - l a t e r a l l y
1 2 .5 c e n tim e te rs m e d i o - l a t e r a l l y ,
v e n tra lly .

and 2 8.5 c e n tim e te r s d o rs o -

The t i s s u e o f p la n e one i s

uniform in appearance

e x c e p t i n R R 1 B w here an a r e a 3 m i l l i m e t e r s i n d ia m e te r i s
fo u n d or y e llo w is h g ra y c o lo r w ith p ro m in e n t i n t e r l o b u l a r
In the

second p lan e

first,

e x c e p t n e a r th e zone s e p a r a t i n g th e f r o n t and r e a r

q u arters.
The c u t

th e ap p earan ce i s n o t as uniform a s th e

O th erw ise,

th e in te rlo b u la r

of c o n n e c tiv e t i s s u e h a s t a k e n p l a c e a t

expense or th e

secreto ry tis s u e .

is

g iv in g r i s e

d isco lo red ,
H.

s e p ta a re p ro m in en t.

su rfa c e of th e udder in the t h i r d p lan e in d ic a te s

p ro life ra tio n

sep ta.

th e

I n a d d i t i o n much o f t h e t i s s u e

to a p a tc h y y e llo w is h -g ra y a p p e a ra n c e .

M icrosconic f in d in g s - In the f i r s t

a r e a s o f polym orpho nuclear i n f i l t r a t i o n
ly m p h o cy tic r e s p o n s e .

th at

plane are lo c a liz e d

to g e th e r w ith a lo c a l

Num erous f o c i o f e x u d a t i o n o f p o l y ­

m orphonuclear c e l l s a re p r e s e n t .

The s e c t i o n from R R 1 B

rep re se n ts
p lan e

su b-acute m a s titis .

of

one i n d i c a t e s a l im i te d , f o c a l i n t e r s t i t i a l m a s t i t i s

w ith areas

of a c u te ex u d ativ e m a s ti t is .

The a l v e o l i
are g re a tly
p resen t,

o f p l a n e tw o a r e

th ick en ed .

sm all and th e a lv e o la r w a lls

Numerous s m a l l f o c i o f i n f e c t i o n a r e

w h ic h a r e c h a r a c t e r i z e d by a f i b r i n o u s e x u d a te w i t h

lo c a liz e d areas
in filtra tio n
changes a re
liu m .

The p a t h o l o g i c a l p i c t u r e

of fib rin o u s

e x u d ate and p o ly m o rp h o n u c le a r

t o g e t h e r w ith a ly m phocytic re s p o n s e .

D egenerative

ev id en t throughout in v o lv in g d e s tru c tio n

M arked f i b r o s i s

of i n t e r s t i t i a l

tissu e

is

of e p ith e ­

e v id en t.

S im ila

changes a re p re s e n t in th e t h i r d p la n e .
T h e p r o c e s s e s i n p l a n e tw o a n d t h r e e a r e

of lo n g e r d u r a t i o n

th a n th o se of th e f i r s t p la n e a s ev id en ced by th e a re a s of
fib ro sis

and d e g e n e r a t i o n of th e e p i t h e l i u m .

f i b r o s i s in the

a lv e o la r w alls

a d d itio n th e re are several

The a r e a s o f

in d ic a te healed le s io n s .

In

sm all f o c i of i n f e c t i o n in v o lv in g

a n y w h e r e f r o m t w o t o a p p r o x i m a t e l y 20 a l v e o l i .

These a re

c h a r a c t e r i z e d by a f i b r i n o u s e x u d a te w ith l o c a l i z e d a r e a s

of

p o ly m o rp h o n u c le a r i n f i l t r a t i o n w ith d e f i n i t e ly m p h o c y tic and
m acrophagic c e l l u l a r r e a c t i o n .
A l l 12 q u a r t e r s

or the th r e e

cows w e r e i n f e c t e d w i t h

S t r e p , a g a l a c t i a e f o r p e r i o d s v a r y i n g fro m two weeks t o
and o n e - h a l f m o n th s.
12 q u a r t e r s ,
fiv e

E xudative p ro c e s s e s a re p r e s e n t

w ith p ro d u c tiv e p ro c e ss e s

q u arters.

two

in a l l

i n 10 a n d f i b r o s i s

The q u a r t e r s n o t y e t s h o w i n g f i b r o s i s

in

or w ith

no p r o d u c t i v e p r o c e s s e s i n e v i d e n c e a r e o f r e c e n t i n f e c t i o n .

S ix of

the

12 q u a r t e r s

In a l l

q u arters

show s u b - a c u t e i n t e r s t i t i a l m a s t i t i s .

th e p ro c e ss e s of p la n e th re e a re

of lo n g e r

d u r a t i o n t h a n t h o s e o f p l a n e tw o a n d s i m i l a r l y t h o s e

of plan e

two a r e o f l o n g e r d u r a t i o n t h a n of p l a n e one a s e v i d e n c e d by
the a re a s of f i b r o s i s ,

p ro du ctiv e p ro ce sses,

of th e e p ith liu m .

The a l v e o l a r w a l l s

are fib ro tic ;

in d ic a te s healed le s io n s .

th is

tim e a l l f o u r q u a r t e r s of t h i s
The S t r e p . a g a l a c t i a e

and d e g e n e ra tio n

i n t h e u d d e r o f cow H

cow show a c u t e ,

At th e

same

ex u d ativ e p ro c e ss e s .

i n f e c t i o n w a s o f two a n d o n e - h a l f m o n t h s

d u ratio n .
T h ese f i n d i n g s a r e i n harm ony w i t h t h o s e r e p o r t e d b y t h e
A nim al P a t h o lo g y d e p a r tm e n t
re su lts

of t h is

of M ic h ig a n S t a t e

study in d ic a te

th at,

th e

d u ratio n .

(3)

when s t r e p t o e o c c i c

t i o n becomes e s t a b l i s h e d i n t h e u d d e r,
recent in ju ry

C o lleg e

wT h e

in fec­

e v id e n c e o f a c u te and

can u s u a l l y be fo u n d i n t h e u d d e r r e g a r d l e s s

of

S t r e p t o c o c c i c m a s t i t i s may t h e n b e i n t e r p r e t e d

as a chronic b u t p ro g re s s iv e p r o c e s s .”

Summary
A ty p ic al stra in

of S tr e p . a g a l a c t i a e , r e c e n tly is o la te d

irom a c ase o f c h ro n ic m a s t i t i s ,

was u s e d i n e x p e r i m e n t a l l y

i n d u c i n g s t r e p t o c o c c i c m a s t i t i s i n norm al cows, i . e .
w ere f r e e

from t u b e r c u l o s i s ,

Bang’ s d is e a s e ,

cows t h a t

and s t r e p t o c o c c i c

m astitis.
T h e cows s u b j e c t e d t o e x p e r i m e n t a l e x p o s u r e b e c a m e i n f e c t e d
o n ly a f t e r r e p e a te d ex p o su re by d ip p in g the u n in ju r e d t e a t s
th e

c u ltu r e or a f t e r d ip p in g of in ju r e d t e a t s

When t h e t e a t s w e r e i n j u r e d ,

su ffic ie n tly

d e v e lo p e d a s a r e s u l t o f one e x p o s u re .
cows t o t h e s t r e p t o c o c c u s p e r o s ,
venous ro u te s

did no t r e s u l t

in to

th e

in to

cu ltu re.

to draw b l o o d ,

in fec tio n

R epeated exposure of th e

or by th e

subcutaneous or i n t r a ­

in strep to co ccic m a s titis .

Of t h e

s i x cows u s e d i n t h e s e e x p e r i m e n t s f o u r becam e i n f e c t e d by d i p p i n g
th e t e a t s
the

in to

the

cu ltu re,

c u l t u r e and one

(th e

one b y d i p p i n g t h e

c o n t r o l cow o f t h e

e x p e rim e n ta l e x p o su re b u t exposed to
o f b ein g s ta b le d

in

These r e s u l t s
to co c cic m a s titis
are

the

t h e same b a r n w i t h
in d ic ate

the

s e c o n d year-) w i t h n o

stre p to c o cc u s as a r e s u l t

the i n f e c t e d

d iffic u lty

cows.

of co n tro llin g

w ith in a h e rd even though th e

in fected

strep ­
cows

s e g r e g a t e d f r o m t h e n o n i n f e c t e d cows a n d s a n i t a r y p r o c e d u r e s

a r e em ployed i n h a n d li n g th e d a i r y h e r d .
of v alu e in th e
the

lacerated te a t in to

first

m eans.

Such p ro c e d u r e s a re

c o n tro l o f i n f e c t i o n s in c e the

c o n t r o l cow o r

y e a r s s t u d y was p r o t e c t e d from i n f e c t i o n by t h e s e

The c a s e i n n i t r o g e n ,
leu co cy te

co n ten t,

w h ey n i t r o g e n ,

pH a n d c h l o r i d e c o n t e n t o f t h e m i l k d i d

n o t v ary g r e a tly p r i o r to in f e c tio n .
i n f e c t i o n the

In g en eral,

v alu es w ith re s p e c t to

o th e r d e te rm in a tio n s gave in c r e a s e d

the

c o m p o s itio n of th e m ilk .

The q u a l i t y o f th e m ilk p ro d u c e d ,
g r e a t l y re d u c e d as m easured by the
m eth y len e b lu e re d u c tio n t e s t .

the

fo llo w in g in f e c tio n ,

stan d ard p la te

Three of th e

f i r s t m onth a f t e r i n f e c t i o n ,

i n th e t h i r d m onth.
dropped from c l a s s

c o u n t,

and t h e

c e n tim e te r d uring

two i n t h e s e c o n d m o n th a n d one

The m e t h y l e n e b l u e t e s t r a t i n g
one t o

was

cows g a v e m i l k w i t h

c o u n t o f g r e a t e r t h a n 1000 p e r c u b ic

m onth a f t e r

fo llo w in g

c a s e in n i t r o g e n and cu rd t e n s io n of th e m ilk

w ere d e c r e a s e d , w h ile th e

a b acteria

and cu rd t e n s i o n ,

c l a s s tw o, t h r e e

of the m ilk

or fo u r w ith in

on e

i n f e c t i o n i n f o u r c o w s , w i t h i n t w o m o n t h s i n o n e cow

a n d w i t h i n t h r e e m o n t h s i n o n e cow.
Th e v a l u e o f t h e v a r i o u s t e s t s
strep to co ccic m a s titis ,
1. m icro sco p ic t e s t ,

thybrom ol t e s t

ex p erim en tal

in d e c re a sin g o rd er of efficiao icy a re :

2. p h y s i c a l e x a m i n a t i o n of t h e u d d e r .

3. leu c o c y te count of m ilk ,
5.

in d e te ctin g

4.

ch lo rid e

co n ten t

of m ilk ,

(pH) a n d 6 . p h y s i c a l e x a m i n a t i o n o f t h e m i l k .

E x p o s u r e s o f cows t o S t r e p , a g a l a c t i a e a n d i n f e c t i o n o f t h e
u dder by t h i s

o rg an ism d id n o t a l t e r th e c e l l u l a r o r hem oglobin

c o n te n t of th e b lo o d .

The n o r m a l v a l u e s ,

for

the

cows s t u d i e d ,

are p resen te d in th is paper.
E x u d a tiv e p ro ce sses

of the th r e e
processes

were p r e s e n t i n a l l tv /e lv e q u a r t e r s

e x p e r i m e n t a l cows s l a u g h t e r e d , w i t h p r o d u c t i v e

i n 10 a n d f i b r o s i s

in f iv e of the

q u arters.

In a l l

q u a r t e r s t h e p r o c e s s e s ot* p l a n e t h r e e w e r e o f l o n g e r d u r a t i o n
t h a n t h o s e o r p l a n e two a n d o f p l a n e tw o t h a n t h o s e o f p l a n e
one.

The e v i d e n c e p r e s e n t e d i n d i c a t e t h a t

strep to co ccic

m a s t i t i s m ay h e c o n s i d e r e d a s a c h r o n i c h u t p r o g r e s s i v e
co n d itio n .

so.

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2.

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5*

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13

Doan

*

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ACKNOWLEDGMENT

I w i s h t o a c k n o w l e d g e my i n d e b t e d n e s s t o
D r . W ard G i l t n e r ,

Dr.

C. D. B a l l f o r t h e i r
t h i s problem .

E. T. H a llm a n , a n d P r o f e s s o r
i n t e r e s t and c o o p e ra tio n in