198 ILLINOIS STATE DAIRYMEN'S ASSOCIATION. 



I have in mind a case where there was a herd of twelve 

 animals, they were divided into two parts and each six animals 

 kept separate from the other six animals. In one side a tuber- 

 culin animal was introduced and every animal on that side ac- 

 quired the disease and in the other side three out of six had it. 

 They got it from the common drinking trough by this animal 

 drooling into the tank and the others drinking out of the same 

 trough. They can get it even though the animal does not come 

 into direct contact with the other animals. 



Member: Suppose your individual bowls are connected 

 with the same pipe? 



Prof. Russell : There is an element of danger in that of 

 course. 



Member: Suppose we had a herd of twelve and only one 

 reacter. If we killed that one would that prevent the spread of 

 the disease? 



Prof. Russell: Yes, by disinfecting the barn and the 

 stall. One of the conditions in which tuberculin test does not 



give the proper answer is the time between the taking in of the 

 diseased germ and the period of incubation, the disease has not 

 developed. There is a period of a few weeks' time that that 

 animal will not react because there is no tubercular tissue. You 

 let that animal stay until the tuberculosis tissue is there and 

 then you will get a response, therefore my course of action would 

 be this : Suppose you have twenty-five in your herd and find 

 ten react. You take out those ten, yet there is a possibility that 

 some few of the fifteen inhaled the germ. I would retest that 

 herd every three or four months. If I did it now I would retest 

 them in May, that is a sufficient time. If there are any animals 

 which are going to respond you would get them on this test. 

 You see, if you have gotten tuberculosis in your herds it requires 

 the examination and the elimination of the reacters and then a 

 retest a few months later. After you have eradicated the dis- 

 ease a test every year or two is sufficient. 



