Bovine Tuberculosis. 121 



appreciates the necessity of complying with every precaution necessary 

 for obtaining the correct results of the test. If the cows come from a 

 tuberculous herd they should be retested in a few months. Russell has 

 pointed out the great danger of buying cows from infected herds without 

 the proper use of tuberculin. 



The handling of tuberculous herds. 



In herds in which the disease already exists to a greater or less 

 extent, the problem is far more difficult. The diseased animals sooner 

 or later become a source of expense and loss rather than profit. The 

 danger of spreading the infection to calves, swine and possibly children 

 by the use of infected milk is too great to take chances with tuberculous 

 cows. The loss of valuable strains of animals and the stigma of having 

 a diseased herd are further reasons for eliminating the disease. It is 

 clear that a dairyman cannot afford to have tuberculous cows in his herd.* 

 The question is, how can a man who has such a herd eliminate the 

 disease with the minimum loss? 



There are at least three procedures to choose from: (i) The total 

 destruction of the infected animals; (2) their slaughter for beef under 

 proper inspection, procuring the meat value of those that are only slightly 

 infected; (3) the application of the Bang method. 



(i) The slaughter of infected aiiiuials. The plan of total destruction 

 (except for fertilizer purposes) is based on the assumption of State aid 

 for at least partial compensation of the owner. This method has not 

 proved entirely satisfactory because of lack of appropriation to pay 

 for the cattle and, further, because it calls for an unwarranted destruction 

 of property in cases of annuals suitable for beef that are found upon post- 

 mortem to be oily very slightly diseased. In many herds where a large 

 number of animals react and where the infection has not been of long 

 standing, a very large percentage of the cattle have a beef value, but the 

 few badly diseased animals have no value and their destruction is the most 

 economic disposition to make of them. If the herd has been infected 

 for a long time, a large percentage of the animals are liable to be suffering 

 with advanced generalized tuberculosis. 



(2) Utilising slightly infected animals for beef. The plan of using the 



^Tuberculosis destroys by death a certain number of animals after the disease 

 has become established in a herd. 



Tuberculosis causes a waste of food by feeding- it to animals that are diseased 

 and cannot ffive an adequate return. 



Tuberculosis causes heavy losses by infecting- other animals, such as swine, 

 calves and adult cattle through the milk and by contact. The enormous annual 

 lost trom tuberculosis in swine illustrates the latter point. 



Tuberculosis reduces the productive and market value of the cows. As soon 

 as there is physical evidence of its existence the animals have practically no 

 market value. 



Tuberculosis destroys the good reputation of a herd, which renders it diffi- 

 cult to sell the animals and often to dispose of their products. 



