124 ILLINOIS STATE DAIRYMEN'S ASSOCIATION 



possibly one^third or one-half of the area. The progress 

 depends upon the degree of infection found and the co-op- 

 eration furnished by the owners. 



In 1910 the Bureau of Animal Industry took up the 

 eradication of tuberculosis from the herds in the District of 

 Columbia, which has an area of 60 square miles. At that 

 time 1,701 cattle were found. Every animal was tubercu- 

 lin tested; of the total number, 321 cattle, or 18.87 per 

 cent, were tuberculous. The reactors were removed from 

 the herds and, in most instances, were slaughtered. The in- 

 fected barns, sheds, and premises were cleaned and dis- 

 infected. 



Each year since the inauguration of the campaign all 

 the cattle have been tuberculin tested with the result that 

 the infection has almost disappeared. 



There are States in which tuberculosis exists to less 

 than 1 per cent among all the bovine population. The plan 

 of carrying on eradication in several counties at the same 

 time in those States is practicable and is being conducted in 

 a number of States. 



Before undertaking the work in any area, large or 

 small, the cattle owners should be consulted, and unless 

 they are willing to lend their earnest co-operation and 

 know the sacrifice they may have to make, it is inadvisable 

 to start. The better the organization and the more nearly 

 perfect the plans are made, the more efficiently the work 

 should progress. 



The larger herds, especially around cities and those 

 supplying milk locally and for shipment to other cities, 

 should be tested before the small lots. If it is known that 

 the herds are but slightly infected, the intradermic method 

 should be employed, as faster progress can be made with it 

 than with the subcutaneous test. If reactors are found in 

 using the intradermic test, the entire herd should be tested 

 subcutaneously within a short time. The ophthalmic test 

 may also be used in conjunction with the subcutaneous in 

 "check" testing herds. General experience shows that it is 

 sound practice, if there is any doubt, to use all three meth- 

 ods of testing with tuberculin. Such a policy is especially 



