120 Tuberculosis 



A cow effected with tuberculosis of the lungs coughs chiefly at feed- 

 ing and watering times, which is especially noticeable after exertion. 

 If an effected animal happens to be in front of a healthy animal at feed- 

 ing or watering time and the effected animal coughs the spray from her 

 mouth into the nosirils of the healthy animal, the healthy animal has a 

 good chance to become infected. In the same way it is possible for an 

 infected animal to infect the water or feed of healthy animals. Where 

 animals are closely confined, the spray may be carried by dust particles, 

 since a dust particle is in size to bacteria as an aeroplane is to a man. 

 About 50 per cent of the tubercular cattle have the disease in the intes- 

 tinal canal. As inferred above, a tubercular animal may infect food by 

 breathing or coughing, especially in close quarters. Infection does not 

 occur so often in the open pastures for sunlight soon kills tubercular 

 bacteria, but they will live many months out of sunlight. Many ani- 

 mals effected after they are killed show tuberculasis in more than one 

 organ. That is, the same cow often has the lungs and intestines both 

 effected, due probably to swallowing lung expectorate. 



SYMPTOMS 



Tuberculosis takes a chronic course in cattle and symptoms do not 

 develope till the disease is well advanced. Fully eighty-five per cent of 

 the cattle that react to the tuberculin test have no symptoms of tuber- 

 losis or any other disease, but after slaughter, the disease can be found 

 in one or more organs of the body. 



The lung form of tuberculosis is probably accompanied by more 

 accurate symptoms than are found when any other organ is effected. A 

 weak, slow, dull, dry cough at feeding and watering time is probably 

 the most noticeable symptom. This cough is accompanied usually with 

 one or more of the following symptoms. The hide is leather like, the 

 hair stands erect, sunken eyes, and cows are usually hard to keep in con- 

 dition, but the appetite is not lost till the very last stages of the disease. 



In the worst intestinal form, an incurable diarrohea or constipation 

 developes in the last days of the disease. 



The symptoms of other forms of tuberculosis are variable in the 

 different organs, and I do not consider a discussion of the same would 

 be of any advantage. 



The tuberculin test for tuberculosis is very reliable and is the only 

 certain way to diagnose the disease, provided the animals are stabled 



