46 MASTITIS OF THE COW 



Udder-infection 



The streptococcus causes milk-infection and acute 

 stroma-infection. The milk-infection is the most important. 



MILK-INFECTION [PareuchT/matous Mastitis] 



This is almost always primary, very seldom secondary. 

 The primary milk-infection as a rule is caused by infection 

 through the teat canal, seldom through the rupture of 

 tubuli in fresh wounds. The secondary milk-infection is 

 one following the embolic stroma, in- 

 fection. It is very infrequent indeed. 

 The local condition is originally con- 

 fined to one quarter, as is the usual case, 

 but later other quarters may become 

 infected. 

 Fig. 9— Typical chronio Tlic Drimarv iufectiou varies con- 



Btreptomycosia. Milk infec- •*• •' 



^ ^(x'?5orTpTthXi siderably in quantity and quality, 

 cXlhow"w?ar^tS depending upon the virulence of the 

 iTTntralobuitrconSve iufcctious orgaulsm and the condition 



tissue thickened. Tubules />ii ii /i* /»■ i'\ 



compressed. Cells in the in- oi thc udder ( timc aitcr calvmg). 



tralobular connective tissue _^ , , . .. ., -, 



and within the tubules. A j\ odular uccrosis can be produced, 



moderate number of strep- i i i i t rv* 



tococci were demonstrated althOUffh I haVC UCVCr SCCU dllFuSC 



in the tubules with bacterial ~ 



^*^'°^- necrosis in this infection. 



The quantity and quality of the inflammation varies 

 with that of the primary lesion. 



Since the infectious organisms cannot liquefy the 

 coagulation necrosis, the exudate often shows a decidedly 

 croupous character. 



An infectious organism of low virulence which only 

 produces a circumscribed inflammation in the parts around 

 the base of the teats can easily induce a chronic progressive 

 condition. The quantity of milk is only slightly diminished 

 by this condition, which is of little importance in the be- 

 ginning. It is, however, a sufficiently good culture medium 



