Bovine Tuberculosis. 125 



Sonic principles to be observed in the elimination of bovine tuberculosis. 



If tuberculosis is not allowed to spread to uninfected animals and the 

 infected ones are disposed of as promptly as possible, tuberculosis will 

 soon disappear. In facing the discouragements of finding tuberculosis 

 in his herd, the dairyman should consider these conditions : 



1. There are some cattle suflFering with advanced tuberculosis. These 

 are of no value, but a menace to the health of the herd and consequently 

 should, for economic reasons, be promptly destroyed, 



2. There are many infected, though but slightly diseased animals, 

 that are poor milk producers but which do have a good beef value. 



3. There are presumably many valuable strains of cows and many 

 high bred animals that are infected though but slightly diseased. The 

 value of these animals is in their ofifspring quite as much or more than in 

 their milk production. The Bang method affords a means for preserving 

 these animals and procuring their offspring without danger to others. 



4. There are large numbers of uninfected herds, and many cows in 

 the infected ones, that should be carefully protected from infection, 



5. Tuberculosis can not spread unless the bacteria that produce it 

 are brought by some means to the uninfected animals. They are most 

 commonly carried by infected individuals or their products. 



Practical procedure. — As it is to the advantage of every cattle owner 

 to have a sound herd, the greatest progress will be made in the eradication 

 of tuberculosis when the greatest number of owners take up the work of 

 elimination for themselves with the aid of competent veterinary advice. 

 The first steps to be observed in the procedure against tuberculosis may 

 be summarized as follows : 



1. Promptly eliminate from the herd all animals that have tubercu- 

 lous udders or that give evidence of being tuberculous. This will greatly 

 reduce the danger from the milk, 



2, As soon as possible, have the tuberculin test applied to all the 

 remaining animals to ascertain which individuals are infected. These 

 are the ones that are still dangerous to the herd, 



3, Separate the well animals from the infected animals. When the 

 reactors are pointed out, the most economic method of dealing with them 

 must be determined from the local conditions. 



4. The stables is which the diseased cattle were kept should be 

 thoroughly disinfected. 



5. The non-reacting animals should be tested every six months until 

 all those previously infected are detected and removed. This will leave 

 a sound herd which will remain so if properly protected, 



6, In buying cattle, great care is necessary not to bring infected 

 animals into the sound herd. They should be carefully tested with 

 tuberculin, and retested in three to six months and all reactors removed. 



