DISEASES COMMUNICABLE IN MILK 



45 



that lays heavy toll on both man and beast. One of the great advantages 

 it possesses is that it has no ill effect whatever on the health of cattle 

 that are not affected with tuberculosis, either when a single injection is 

 given or when it is applied repeatedly as in using it in the eradication of 

 tuberculosis from a herd. 



Results of Tuberculin Testing. In the United States and Europe 

 tuberculin testing of cattle has been widely used with the result that 

 dairy cattle have been shown to be extensively infected with tuberculosis. 

 Some of the results obtained in this country may be noticed. 



Tuberculin Testing in Wisconsin. The State of Wisconsin has used 

 the tuberculin test more extensively and effectively than have any of the 

 other States. Russell says that it is certain that two-thirds of the 

 herds of the State are free from tuberculosis. Work was begun in 1893 

 with the testing of the college herd and has been pursued in the State at 

 large ever since. It is estimated that at the present time the tuberculin 

 test has been applied to from one-sixth to one-fifth of the milch cows. 

 Hastings says it is certain that not over 5 per cent, and possibly not over 

 4 per cent, of the dairy cattle are tubercular but he also says that while 

 the percentage of tuberculous cattle has decreased the number of infected 

 herds has undoubtedly increased and that the great problem in Wiscon- 

 sin is to prevent the introduction of tuberculous animals into herds now 

 free from the disease. The extent to which the tuberculin test has been 

 applied may be seen in Table 19. 



TABLE 19. TUBERCULIN TESTING IN WISCONSIN, 1893-1912 (HASTINGS) 



(a) Slaughter demonstrations begun. 



(b) Indirect compulsory legislation. 



(c) Estimated. 



(d) Indirect compulsory legislation repealed. 



The Wisconsin methods are worthy of close study not only because 

 they have been tried on a large scale but because of the policy of the 

 State in not confining the testing with tuberculin to veterinarians but 



