100 THE COW IN HEALTH AND DISEASE 



gina during copulation has the power of passing 

 the mucous plug in the neck of the uterus, gaining 

 access to the uterus where it sets up a catarrhal 

 inflammation of the mucous membranes lining 

 the uterus and also the membranes covering the 

 foetus and also the attachments between the cho- 

 rion or outside layer of the covering of the foetus 

 and the cotyledons, to which the membrane is 

 attached. This produces a secretion and grad- 

 ually the membrane becomes loosened from the 

 cotyledons or their attachments and then the 

 contents of the uterus or the foetus is expelled. 

 During this diseased condition, the bacilli caus- 

 ing this condition may gain access to the foetus 

 itself. Sometimes, however, the foetus is not ex- 

 pelled but simply mummifies and is retained to 

 full term and sometimes even longer. A cow 

 will often abort twice, but not usually more than 

 three times at the most. 



Cows most often abort in the fifth or sixth 

 month and mares from the fourth to eighth 

 month of pregnancy. Animals that are preg- 

 nant for the first time will usually abort earlier 

 than those that are older or that aborted prev- 

 iously. Abortion may occur at an earlier or later 

 date, however. The first symptoms that are no- 

 ticed are a catarrhal inflammation of the genitals 

 with a swelling of the vulva and an inflamma- 

 tion of the vagina with a mucous discharge which 

 is always dirty, but may be clear or of a dirty 

 gray or occasionally a bloody discharge. In cows 

 the milk flow is diminished and looks much like 



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