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147 



usually iu adjoining' stalls, whieli miscarry, sometimes 

 one after another in consecutive order down the line of 

 stalls. The disease may be confined to one side of the 

 barn for years. If the bull distributes the infection, in- 

 fection occurs promiscuously through the herd. 



2. Allowing the bull to serve infected cows or pat- 

 ronizing a bull which has served infected cows. 



3. Shipping in cars and keeping in pens or stalls 

 \\ hich have been occupied by aborting animals. 



4. An attendant who removes the afterbirth of an 

 infected cow has been known to transmit the disease to 

 other cows operated on afterwards. 



5. It is possible to have the infection transmitted 

 from one herd to another by the interchange of help or 

 by securing milkers, herdsmen, etc., from dairies where 

 the disease prevails. Overalls and like clothing which 

 are worn at one farm go with the owner to new locali- 

 ties, of times without even a washing. 



6. The manner of handling manure in cow barns 

 w here one trench receives the excrement from a whole 

 row of cows in open stalls may be responsible for the 

 spreading of the disease in the herd. It is the rule to 

 begin at one end of the trench and push the manure 

 along uutil enough accumulates to shovel in quantities, 

 thus the discharge from an aborting cow may be scat- 

 tered behind a dozen or more animals. 



How the germ gains access to the genetal organs may 

 be explained as follows: 



When the bull is infected, it is easily understood how 

 germs would be introduced into the vagina at copula- 

 tion. There are a number of instances on record where 

 the purchase, borrowing or patronizing of bulls have 

 been responsible for serious outbreaks. More often the 

 disease spreads from one cow to the next nearest, and so 

 on as already indicated. 



