FACTORS INFLUENCING BEEF PRODUCTION 263 



become very thin, the coat of hair is more or less harsh 

 and staring, there is diarrhea, bloat and weakness, and cough- 

 ing may ensue when rising after lying down. 



Tuberculosis is very contagious, and one affected cow 

 will spread the disease amongst a herd and ruin it. The 

 germs live for a long time in dark stables, in mangers and 

 manure trenches, etc. When the udder is affected, they 

 also pass off in the milk, and, if this is fed to healthy calves 

 or pigs, they usually contract the disease. The tubercular 

 germ is killed by a few hours exposure to sunlight, and is 

 destroyed in milk that is heated up to 145 degrees for 25 

 minutes, and then suddenly cooled to 40 degrees. For 

 family use, milk heated to 165 degrees for 5 minutes and then 

 cooled to about 40 degrees, will be safe to use. 



The universal method of determining whether a cow has 

 tuberculosis to-day is by the tuberculin test. A serum is 

 produced in the laboratory by growing the germs of the 

 disease, in a solution, which at a certain stage of develop- 

 ment is boiled to destroy all germ life. If some of this solu- 

 tion is then injected beneath the skin of a tubercular cow, 

 her temperature during a few succeeding hours will go 

 through a rather steady rise of two degrees, and then fall. 

 If she has no tuberculosis, her temperature will not change. 

 There is also another test, the intradermal, in which the 

 serum is injected between the outer and inner layers of skin, 

 and still another test, the ophthalmic, in which tuberculin 

 is applied m the eye. 



Every herd should be tuberculin tested, and each reactor 

 should be killed, subject to inspection. If the carcass itself 

 is not affected, and the disease is confined to the organs 

 that are removed, the meat is suitable for food. In 1921 at 

 10 Armour Packing Houses, 4,728 cattle were held by the 

 Government inspectors for further examination, because of 

 suspected tuberculosis. Of these 76.48 per cent were con- 

 demned as unfit for food.* 



♦Progressive Beef Cattle Raising, Published by Armour & Co. 1922. 



