Tuberculosis in Line Stock. 
29 
grade cattle, or pure breds not specially valuable for breeding, it 
will probably be more economical to have them slaughtered than to 
hold them in quarantine. Of course the fact is recognized that in 
States and communities where tuberculosis exists extensively the 
slaughtering of all reactors is impracticable. In such instances the 
infection can be reduced on all the farms by keeping the tuberculous 
animals separate from the healthy ones. The tuberculous cattle are 
kept under quarantine restrictions until no longer profitable; mean¬ 
while the healthy animals are safe from the danger of infection. 
RETESTING. 
It is rather uncommon for tuberculosis to be eradicated from an 
infected herd after one tuberculin test. After the removal of 
reactors the herd should be retested at the expiration of six months, 
and a second retest may be advisable six months later, but the prac¬ 
tice of testing herds more frequently than that is not usually advised. 
After two or three semiannual tests the herd should not be tested 
oftener than every 12 months. While the subcutaneous test is con¬ 
sidered preferable for gentle cattle, the ophthalmic and intradermal 
methods of testing may be employed to advantage as adjuncts to it; 
and it is believed that in some instances herds may be freed of tuber¬ 
culosis earlier by the judicious use of all three methods. No general 
outline can be given as to when all three tests should be employed; 
the matter should be left to the judgment of the veterinarian under 
whose direction the work is carried on. 
MARKING ANIMALS FOR IDENTIFICATION. 
It is very important to mark properly all cattle which react to 
the tuberculin test, so that they may be easily identified as affected 
with tuberculosis. One method that is quite generally used is that 
of branding; a letter “T” about 2 inches high is branded on the 
lower jaw, or sometimes it is placed on other parts of the body where 
it can be seen readily. In addition to the branding it is advisable 
to tag the reacting animals so that one may be identified from 
another, and in that way the results of the post-mortem examination 
can be connected up with the reporting of the tuberculin tests. The 
tag is usually placed in the ear of the animal and contains a serial 
number as well as the word “Reactor.” 
Another method that is sometimes used is the punching of a letter 
“T” out of the ear, and it has been quite satisfactory. 
The marking of cattle that have passed the tuberculin test is a 
matter that is being handled in different ways throughout the United 
States, and it is believed that the present methods of marking will 
be improved. In some cases a metal ear tag is used and in others 
certain marks of identification are tattooed in the ear. Tattoohig 
