Bischoff & Co., it is stated : "As a rule only apparently healthy 

 animals at the age of from two weeks to three months (for the 

 first inoculation) are chosen. In such calves a previous tuberculin 

 test is not necessary, even if the animals were taken from a notori- 

 ously tubercular herd." However, Bischoff & Co. wrote that the 

 tuberculin test should be made, and accordingly it was, except in a 

 few cases which a year afterwards proved to be non-reacting. We 

 found the normal temperatures very variable, as would naturally 

 be expected in such young animals. We believe that the tuberculin 

 testing of calves less than sixteen weeks old is unreliable as an 

 indication of tubercular infection. Nevertheless none of the calves 

 which showed an abnormally high temperature after injection were 

 vaccinated. 



Another requirement imposed by Bischoff & Co. was that the 

 calves be kept from possibility of tubercular infection until four 

 months after the second vaccination. This in a measure was possi- 

 ble with the calves secured from the non-reacting herd, and the 

 danger to the calves in the other herd was obviated as much as 

 possible by weaning them at as early an age as seemed expedient. 

 As soon as possible the calves were all removed to the University 

 Farm, where at that time there were no tubercular cattle. 



In the winter of 1908 the calves were all tested with tuberculin 

 and none reacted. They were then subjected to infection by placing 

 in their pasture five reacting cattle that were apparently in an 

 advanced stage of tuberculosis. They were associated with the 

 calves in a twenty-acre pasture and in a corral. Within six months 

 these five cattle had all died of tuberculosis as proven by autopsy 

 in each case. During the winter of 1909 no tubercular animals were 

 with the young cattle. They were fed under a shed during rainy 

 weather. Other than this they lived out-of-doors. In March, 1909, 

 ten reacting dairy cows were placed in the corral and pasture with 

 the young cattle. The proofs that several of these cows were af- 

 fected with open tuberculosis are given later in this paper. 



In July, 1909, all the young cattle were tested and the reacting 

 ones sent to an abattoir having federal meat inspection. Special 

 arrangements were made with the abattoir company and with the 

 federal veterinary inspectors for their post-mortem examination. 

 The animals were killed after all other killing was over, and a more 

 searching inspection than usual made. 



Since last July two tuberculin tests have been made on the re- 

 maining cattle, and to date (April 30, 1910) twenty-four of the 

 experimental animals have been slaughtered and found tubercular. 



OF THE TWENTY-TWO VACCINATED CATTLE TEN 

 WERE TUBERCULAR; SIX OF THESE CAME ORIG- 

 INALLY FROM THE NON-REACTING DIARY HERD, AND 

 FOUR FROM THE REACTING DAIRY HERD. OF THE 

 TWENTY-THREE NON-VACCINATED CATTLE FOUR- 

 TEEN WERE TUBERCULAR, SEVEN CAME FROM THE 

 REACTING DAIRY HERD AND SEVEN CAME FROM THE 

 NON-REACTING DAIRY HERD. 



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