134 ANNUAL. REPORT OF THE Off. Doc. 



There is at this time practically complete unanimity of opinion, 

 among- those who have given the subject careful attention, to the 

 effect that the eradication of tuberculosis from a herd without 

 the use of the tuberculin test is such a slow, laborious and uncer- 

 tain process as to be unjustifiable under ordinary conditions; al- 

 though it is known that the losses from tuberculosis in herds may 

 be diminished by subjecting herds to repeated and careful physical 

 examination. By the latter means, the animals that are afflicted 

 with tuberculosis in the most advanced stages, that are excreting 

 the greatest number tubercle bacilli and that are most likely to fur- 

 nish infectious milk may be detected and removed. But the com- 

 plete eradication of tuberculosis must, for the present, at least, 

 depend on the use of the tuberculin test. This is so well under- 

 stood that the demand for the test upon the part of herd owners is 

 growing from year to year. 



After the herd is tested and the animals that are tubercular are 

 pointed out, the immediate question confronting the herd owner 

 and his veterinary advisor is, what shall be done with the animals 

 that have reacted and that are infected with tuberculosis? It is 

 well known that the tuberculin test does not indicate the extent 

 of infection, it merely reveals the fact that the animal is infected; 

 the disease may be extensive or it may be slight. It is frequently 

 impossible by means of the most careful physicial examination, even 

 with the knowledge that the animal has reacted to the tuberculin 

 test, to determine, while the animal is alive, the location or extent 

 of the lesion. But even in these cases the postmortem examina- 

 tion not infrequently shows that the disease is of such extensive de- 

 velopment and is so situated as to permit tubercle bacilli to be 

 excreted by the animal, thus rendering it capable of spreading in- 

 fection to its associates. From this it is clear that cattle that have 

 reacted to the tuberculin test, even though they appear to be per- 

 fectly healthy at the time, are, in many cases, capable of spreading 

 the disease, and all such cattle must be treated as though it were 

 known that they are actually distributing tubercle bacilli. It is 

 not necessary as a sanitary measure, nor is it required by the laws 

 of the State or by regulations of the State Live Stock Sanitary 

 Board, that animals that have reacted to the tuberculin test, and 

 that do not show evidence of advanced or generalized tuberculosis 

 or lulder tuberculosis, shall be destroyed. It is required, merely, 

 that such animals shall be so cared for that they may not spread 

 disease. This means that they shall be kept apart from other cattle, 

 and that their milk shall not be used without jjrevious sterilization 

 or pasteurization in a way that will insure the destruction of the 

 tubercle bacillus. Therefore, if cows that have reacted to the test 

 can be maintained as a separate herd and their milk pasteurized 

 before it is used, this is allowed and encouraged. 



