192 COMMON AILMENTS OF CATTLE 



from bloat. Bloating, however, is not a frequent symptom. 

 The body temperature may be normal, although we more fre- 

 quently find it to be irregular, being inclined to be much higher 

 in the evenings. Tuberculosis of the udder manifests itself 

 by the formation of hard lumps or swellings in certain parts of 

 the gland. Milk from such an udder should not be used, as it 

 is quite apt to be laden with genus. 



The Manner by Which the Disease Spreads. — Tuberculous 

 cows sooner or later give off the germs which may escape, by the 

 mouth, the nose, in the milk, in the manure, and in the dis- 

 charges from the genito-urinary organs. When the germs are 

 thrown off in any of the above-named ways, the disease is known 

 as open tuberculosis. The germs discharged from the mouth 

 and nose are coughed up from the lungs, some of which are 

 swallowed while others are sprayed over the feed in front of the 

 cow. Cows in adjoining stalls may take in these germs with 

 the feed or the water and thus contract the disease. 



The manure and urine from tuberculous animals usually 

 contain the germs and will spread the disease unless properly 

 disposed of. Manure mixed with the germs of tuberculosis 

 may fall into the milk pail or be carried to the milk direct by 

 the cow's tail and thus contaminate the milk. The germs are 

 not removed when the milk is strained. When the disease affects 

 the udder the milk, as a rule, contains the germs in vast numbers. 

 Such milk will readily transmit the disease to young animals. 

 Milk of this kind is also very dangerous to young children. 



The Manner by Which a Herd Becomes Infected. — The 

 principal ways through which tuberculosis may be introduced 

 into a herd are : First, through the buying of cattle from other 

 herds infected with the disease. Buyers should purchase only 

 from healthy herds in order to safeguard their healthy animals. 

 Second, calves may become infected by feeding them milk, butter- 

 milk, or whey from tuberculous cows. Such material should not 

 be fed unless boiled or pasteurized. Third, by allowing healthy 

 stock to mingle with diseased animals. Fourth, by keeping cattle 

 in poorly ventilated, insanitary, dark, and unclean quarters. 



Tuberculin Test — Only a small percentage of tuberculous 



