Bovine Tuberculosis. 123 



the chronic nature of the disease and its tendency to become arrested. 

 The large percentage (35.4 per cent) of dairy cows in Denmark that 

 reacted to tuberculin, suggested the importance of replenishing the herds 

 with healthy cows before the total destruction of the reacting ones. 

 The method is summarized in the following statements : 



1. A herd is tested with tuberculin. The animals that are in a bad 

 condition are slaughtered. The reacting animals that show no physical 

 evidence of the disease are isolated. They are kept for breeding pur- 

 poses. 



2. The offspring from the reacting cows are promptly removed from 

 their dams and fed milk from non-reacting cows, or the pasteurized 

 (heated to a temperature of 85° C. or 185° F.) milk from the reacting 

 ones. The milk of the isolated cows after pasteurization is also used for 

 human food. 



3. If any of the isolated cattle give evidence of the disease advancing, 

 such as enlarged glands or emaciation, they are slaughtered. 



4. The non-reacting animals are tested from time to time, and if any 

 individuals react they are placed with the isolated ones. 



5. The calves that are raised from the reacting cows and which fail 

 to react to tuberculin, are placed in the sound herd. 



It is important to test, with tuberculin, calves that have been born of 

 tuberculous dams and raised on pasteurized milk of tuberculous cows 

 for the reason that it is possible through inadvertent accidents that some 

 of them have become infected. In my observations in various herds, 

 from one to four per cent of the calves brought up under these conditions 

 have reacted to tuberculin at six months of age, but very rarely after 

 that if proper precautions are taken. 



As the sound herd is replenished, the isolated cattle may be fattened 

 and killed, under proper inspection, for beef (See page 273). In this 

 way the people of Denmark have been able greatly to reduce the very 

 high percentage of tuberculous cattle and at the same time to minimize 

 the loss they previously sustained by the death of diseased animals. 



The Bang method, modified to suit the local conditions, has been 

 applied with great success in Hungary, where the reports show that 

 many highly infected herds have been freed of the disease in from 

 four to six years. In Norway and Sweden, the results have been equally 

 good. Professor Regner'^^ states that the percentage of reacting animals 

 among 36,149 cattle was, at the beginning of the application of this 

 method, 33.6 per cent. After a period of two to nine years, in 

 different herds, it has been reduced to 4.7 per cent. 



This method has been applied with success at the Wisconsin Agri- 



*Regner, Gustav. The suppression of tuberculosis among domesticated ani- 

 mals. Eighth International Veterinary Congress, Budapest. Sept., 1905. 



