632 DISEASES OF SWINE 



development of paralysis of the hind limbs. During the breeding 

 season this condition may develop as a result of injuries produced by 

 an overvigorous and heavy boar. After nursing a large litter of 

 pigs, sows are frequently left in a weak, run-down condition, and 

 posterior paralysis is not uncommonly seen in such animals. 

 During the winter months, when hogs are allowed to overcrowd 

 and pile up on top of each other, injuries to the back frequently 

 occur which result in inflammation of the cord and paralysis of the 

 hind parts of the body. 



Indigestion and constipation are regarded as possible causes for 

 the condition. Especially is constipation to be regarded as a 

 possible cause of this paralysis, as the overloaded large bowel may, 

 by pressure upon the spinal column, cause disturbances of nerve- 

 supply and pressure paralysis. 



A condition which very closely resembles posterior paralysis is 

 seen in the acute infectious diseases, and especially in hog-cholera. 

 The condition in these diseases is more due to muscular weakness, 

 however, than to interference with the nerve-supply. 



Symptoms. — The condition may appear very suddenly or, 

 more commonly, it may come on gradually. In practically every 

 case of true paralysis both hind legs are involved. In those cases 

 that come on gradually the animal will first be noticed to have a 

 pecuHar, unsteady gait. The animal is noted to weave from side to 

 side when walking, the hind legs not being able to follow in a 

 straight Une with the front feet. The hind part of the body may 

 be carried very much to one side and sort of dragged after the front 

 portion. In attempting to move or stand the animal gets the hind 

 feet crossed over each other. For a time the animal is able to stand 

 and sort of throw the hind hmbs after the front ones. When the 

 hog so affected lies down there is considerable difficulty in getting 

 up. As the condition advances and grows worse, the weakness 

 becomes more pronounced, and after a time it is impossible to get 

 on the hind legs at all, and the animal simply drags the hind 

 quarters along the ground. 



At the beginning of the attack the general health is usually 

 good. The animal eats well and there is httle disturbance of health 

 or loss of condition for several days. If recovery does not take 

 place, however, within a week or so the animal begins to show signs 



