INFECTIOUS ABORTION AND STEKLITY IN CATTLE* 



Circular No. 40 



BY E. T. HALLMAN_, ANIMAL PATHOLOGIST. 



It is believed that abortion is most frequently introduced into the herd 

 througli the purchase of pregnant or recently freshened cows altliougl; it 

 inny be introduced 1)}' lu'eoding to a neighbor's bull, niid i)«'ili;i]»s in other 

 wjiys not yet fully understood. Newly purchased females, though lliey do 

 not abort, may be carriers of the infection. 



When abortion manifests itself in a herd, immediate steps should be 

 taken to ascertain if it is infectious. This is best determined by a blood 

 examination. Any one may have this test made by sending about one 

 ounce of blood from each animal to be tested to the Bacteriological De- 

 partment, East Lansing, Michigan. 



When abortion first manifests itself in a herd many dairymen are 

 tempted to sell for beef the aborting animals, thinking that the infec- 

 tion may be eliminated in this way. 



It is not advisable to attempt to eliminate the infection in tliis way. 

 There are two reasons why this is so. First, the extent of infection in 

 a herd cannot be measured by the number of abortions since many in- 

 fected animals carry their calves to maturity; and second, when many 

 animals are sold for this reason it becomes necessary to purchase new 

 animals to maintain the herd, and in so doing one is likely to introduce 

 a more virulent strain of infection thaii alreadv exists If aborting, 

 animals are i)ioperly handled they may develop into regular breeders 

 and should not be sold simply because they have aborted. 



There are no known cures for abortion. Many proprietary prepara- 

 tions are to be found upon the market, both medicinal and the so-called 

 bacterins and serums, but none of these have proved sufficiently effective 

 to warrant their recommendation. 



There are no measures by which the infection can be completely and. 

 surely eliminated from a herd other than disposal of the entire herd. 

 It is more likely that once the infection is introduced, it will remain more 

 or less indefinitely, but this characteristic of abortion should not dis- 

 courage one from going on with the cattle business. 



There are measures l)y which one may reduce the percentage of abortion 

 to such an extent that dairying and calf production may be made profit- 

 able. There will perhaps be a few abortions each year but its ravages 

 may be checked. There are no easily applied measures, but ones which 

 require persistent effort, not for a week or a month but for the entire 

 time that one remains in the business of producing milk and calves. 

 The only measures that have proved effective are stable hygiene and 

 disinfection. 



To enable one to most effectively apply these measures one should 

 know the ways by which the abortion bacilli are eliminated from the 



♦Adapted from numbers 1, 2 and 3 of Quarterly. 



