EXPERIME^NT STATIOtSI BULLETINS. 32? 



CONTROL OP THE DISEASE. 



Unfortunately it is not possible at this time to suggest an entirely 

 effective and satisfactory plan of controlling this disease. 



Bacterial vaccines. In our experimental work with the use of bac- 

 terins on pregnant animals and with the use of living cultures of the 

 abortus bacillus on open females we have found that the results have 

 not been encouraging. So far we have been unable constantly to prevent 

 abortion by the use of bacterins on pregnant animals and we are yet un- 

 certain as to the beneficial, or even injurious effects, resulting from the 

 use of living cultures on open females. Others have reported similar ex- 

 periences. 



Carbolic acid. There are a number of so-called abortion cures on the 

 market, none of which we can recommend. The principal constituent of 

 some of the most widely advertised abortion cures is carbolic acid. This 

 drug has been used in the treatment of infectious abortion for many 

 years and is recommended by some but our experience with it in this 

 state has not been entirely satisfactory. 



Methylene hlue. Kecently methylene blue has been recommended. We 

 have had little opportunity to observe the effects of this drug on preg- 

 nant animals in affected herds, however we have seen animals abort on 

 the methylene blue treatment and we have had unfavorable reports from 

 dairymen who have used the drug. Owing to the limited data at hand 

 as to its merits we do not feel justified in recommending it. For the 

 benefit of those who wish to try methylene blue we quote from a per- 

 sonal communication from Dr. Rich of the Vermont Station. "I would 

 say that the interrupted method of giving the methylene blue advised in 

 our preliminary bulletin did not prove as satisfactory as our former 

 method of giving it constantly for from four to six weeks, so for nearly 

 a year we have advised giving about a half ounce daily for at least four 

 or five weeks." He would revise the directions to read as follows: "The 

 opinion of the writer to date is that the treatment should begin early in 

 pregnancy; that 10 to 20 grams (% to % oz.) should be given on silage 

 or moistened grain feed, each day, for four or five weeks." To Dr. Rich 

 is due the credit for having first suggested the use of this drug for in- 

 fectious abortion in cattle. 



Acquired immunity. Occasionally we hear of apparently favorable 

 results from the use of various remedies, but we are convinced that in 

 the majority of cases, the apparent beneficial results are explained by a 

 possible tolerance to the disease which may follow after a previous abor- 

 tion. Many cows abort only once or twice, subsequent pregnances ter- 

 minating normally. 



Sale of aborting animals. Frequently one is advised to sell for slaugh- 

 ter the aborting animals. The disease cannot be controlled in this way 

 since all affected animals do not abort. An animal affected with the 

 disease but not aborting may be as great a source of danger to other non- 

 affected animals as is one aborting. 



Suggested plan. In the light of our present knowledge of the disease 

 the only plan that we suggest for the control of the disease in affected 

 herds, that offers any hope of reward, is one of local treatment of the 

 affected cow, disinfection and sanitation. 



