116 PRINCIPLES AND PRACTICE OF MILK HYGIENE 



been reported, there is no doubt that the milk is injurious 

 to health because numerous cases of meat poisoning are 

 on record from the use of meat from cows slaughtered 

 while suffering from this condition. Cows affected with 

 septic metritis should therefore be removed from the milk 

 stable and the milk should not be used for food. 



RETAINED PLACENTA 



Following retention of the placenta, there is a dis- 

 charge from the uterus which frequently contains par- 

 ticles of the fetal membranes and cotyledons which are 

 undergoing putrefaction, also pus, pyogenic organisms, 

 and putrefactive bacteria. The tail, thighs, and udder 

 become soiled with the discharges and the milk may be 

 contaminated during milking. In cases where the milk 

 has been centrif ugalized and the sediment examined micro- 

 scopically, large numbers of staphylococci and diplococci 

 have been found. The milk will also give a positive re- 

 action to the alcohol test, indicating that the secretion is 

 not normal. Milk from cows with a purulent or putrid 

 vaginal discharge should not be used for food purposes. 

 Such cows should not be placed in the milk stable 

 until the condition disappears, as there is a possibility of 

 the discharge contaminating the milk of the other cows. 



INFECTIOUS ABORTION 



The milk of cows which have aborted contains the 

 Bacillus abortus Bang very frequently, in some cases for 

 months after the abortion. Immediately before and 

 for several weeks after abortion, the bacillus is also elimi- 

 nated through the vagina and may infect the milk second- 

 arily. When the placenta is retained, the vaginal dis- 

 charge also contains pyogenic and putrefactive organ- 



