Bovine Tuberculosis. 159 



The question arises, what can be done with the reacting animals? 

 The examination of a large number of cattle that have been killed 

 after the test, shows that a small number in every herd containing 

 reacting animals are very extensively diseased and would undoubt- 

 edly have died in a short time. These are of no value and should be 

 destroyed. Usually they are poor, and will not take on flesh. A 

 much larger number of the reacting animals are but slightly diseased. 

 These will readily take on flesh and can be fattened and used for l^eef. 

 They must be carefully examined when killed, and if the disease is 

 found to be extensive or in the two large body cavities, the carcass 

 must be condemned. The government meat inspection regulations 

 permit of the use of the meat of slightly tuberculous animals for food. 

 These animals, therefore, have a beef value. 



If the reacting cows are valuable, they can be isolated and kept 

 for breeding purposes by removing the calves at once and feeding 

 them on milk from healthy cows. The milk of the reacting cows can 

 be used if it is sterilized first. 



7. How TO Prevent Tuberculosis. 



As the most common method of introducing tuberculosis is by the 

 purchase of a diseased animal, or feeding the milk of such animals, the 

 most effective way to prevent the disease is not to do those things. 

 Buy all animals on a tuberculin test, and retest after three to six 

 months. Do not feed skimmed milk that comes from tuberculous 

 herds to calves without first sterilizing it. The method is simple. 

 The disease is produced by the tubercle bacilli and if we keep these 

 bacteria away from our cattle they cannot possibly develop tuber- 

 culosis. 



8. Necessity for Field Experiments for the Study of Animal 



Diseases. 



A careful review of our })rescnt knowledge of bovine tuberculosis 

 shows that while we have many important facts concerning it, we still 

 need further information. This information can come only from 

 actual investigation on a considerable number of animals living under 

 what might be considered normal conditions. In order to know the 

 best, or at least the most economical method of dealing with tuber- 

 culin-reacting animals, we need to have more knowledge concerning 

 the recovery of the slightly affected individuals and the conditions of 

 the diseased processes in the cases that fail to react on the second 

 test. We have very definite knowledge as to the means of infection, 



