Blackleg 365 



large part of this country, and causes serious losses in 

 the central and western stock-raising states. 



Calves that are in good condition, or fat, are more 

 likely to contract the disease than those in thin flesh. 

 In some countries, the disease is said to be confined to 

 low -lying pastures; but in the western states it is quite 

 as frequent on the high, dry prairies as on lower lands. 

 It is thought that the germ of the disease does not 

 belong naturally within the animal body; but, taken 

 into the bodies of young cattle, it finds conditions favor- 

 able for multiplying, and produces the disease. Black- 

 leg may develop on pastures and in localities where it 

 has never been known before, and where there seems 

 to be no possibility of the germs having been in- 

 troduced. 



The afifected calf is first noticed lying down apart 

 from the others. If driven up, it is found to be stiff and 

 lame in one leg, or one whole side of the body may 

 be almost useless. There are swellings on some part of 

 the affected leg or side, which, if rubbed firmly with the 

 hand, will be found to be filled with gas and will emit a 

 crackling sound. This is a characteristic symptom of 

 this disease. Calves with blackleg will usually live 

 for some days; only a few recover. 



Well calves should be removed to uninfected pastures 

 or quarters, and given water that has not been contami- 

 nated. Medicinal treatment is of little value. Exer- 

 cise and purging with salts are recommended, the latter 

 being given as a drench in one -half to one pound 

 doses. All susceptible animals should be vaccinated 

 with blackleg virus — a safe and reliable preventive. In 



