ANOMALIES AND DISEASES OF YOUNG PIGS 



215 



Etiology. — This condition is caused by infection, but the specific 

 exciting cause has not been positively identified. The Staphylococcus 

 pyogenes aureus has been isolated from the lesions and was ap- 

 parently present in practically a pure culture. A streptococcus ap- 

 pears to be the exciting cause in some cases, and in other cases the 

 colon bacillus or some of its derivatives have been identified. Bacillus 

 pyocyaneus sometimes causes this condition. The young animals are 

 predisposed to the various types of infection by filthy surroundings 

 and improper care. Some breeders claim that if the sows are per- 



Pig. 42. RACHITIS. Typical standing posture of elghteen-months' old pig 

 affected with rachitis and perhaps rheumatic disturbances also. Note the 

 bowed front legs and enlarged bones. 



mitted to farrow in clean quarters, and are maintained and fed in 

 the proper way, that the pigs will not contract this disease. 



There is evidence of the transmission of the disease in utero from 

 the dam to the foal in horses, but such evidence has not been ob- 

 tained in swine. 



The infection gains entrance through the thrombi in the umbilical 

 vessels. The infecting organisms extend in the thrombus, ultimately 

 reaching the blood stream, by means of which they are disseminated 

 throughout the body. 



