Wisconsin Dairymen's Association / Fortieth annual report of the Wisconsin Dairymen's Association : held at Beloit, Wis., November, 1911. Report of the proceedings, annual address of the president, and interesting essays and discussions relating to the dairy interests
Hastings, E. G.
Tuberculin and its uses, pp. 97-106 PDF (2.1 MB)
Fortieth Annual Report of the DiscussioN. A Member: Professor, that first chart shows that the first and the last cow had the same temperature. Why did you condemn one cow and not the other? Prof. Hastings: These animals were not condemned, the whole herd was slaughtered. The herd was all infected and the whole herd slaughtered. This last animal would always be looked upon as perfectly healthy from the standpoint of the tuberculin test. She may have been one of these animals that we call a ceased reactor, that is, where the disease is dormant in the system and the tuberculin did not cause any disturbance that we could detect, or she may be an animal in which the disease is progressing at the time the test is made, and the disturbance is not great enough to be detected. A Member: Do you find many animals such as that one? Prof. Hastings: It Is absolutely impossible to collect figures on that except under such conditions as this, and yet we know they occur, for we get them in practical work now and then. Frequently a herd is tested and all reacting animals removed, and yet, an animal being killed afterwards for some reason, is found to be diseased. A farmer comes in and says, "I have had my herd tested. The test shows thus and so. I have been told if I tested my herd and took out the reacting animals it would all be over with, the rest would be all right." Of course some explanation must be advanced and often it is not very satisfactory because he has it firmly fixed in his mind that the tuber- culin test is infallible. A Member: Is it possible that if that cow had been given a double dose of tuberculin it would have been more satisfactory? Prof. Hastings: Perhaps with such a cow it would; usually when an animal looks to be perfectly healthy we know of no reason why a double dose should be given. A Member: How would you account for the fact that if a man had his cows tested and they proved all right, but a year later one should die; then he retests the herd and finds the remaining animals perfectly healthy. Prof. Hastings: That first animal might have been in one or the other of the conditions I have mentioned. An animal may have be- come infected recently, you may test her and she does not react, and yet within a year from that time she may get into a diseased condi- tion. A Member: How could the disease be introduced where the herd has been tested and found perfectly healthy, before the retesting in a year? 104
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