600 DISEASES OF SWINE 



to be trampled upon in feed lots or may be accidentally caught 

 under a wagon. Where the herd is allowed to pile up in over- 

 crowded sleeping pens the back often becomes injured, and an 

 acute inflammation of the kidney is the result. 



Exposure to cold, damp weather, especially if the animals are 

 overheated, is often followed by a nephritis. Dipping animals 

 while overheated or in cold weather may result in the production 

 of this disease. Another cause for the disease is the ingestion of 

 irritating chemical substances. This may occur as a result of vari- 

 ous chemical compounds contained in kitchen slop, or as a result 

 of drinking solutions of carbolic acid or bichlorid of mercury thrown 

 upon the ground. 



Primary cases of acute nephritis are not nearly so frequent in 

 the hog as the secondary inflammation, seen as a complication of 

 acute infectious diseases. Practically every case of hog-cholera 

 is complicated by an acute inflammation of the kidneys. So often 

 is this the case that we have already seen how the hemorrhagic 

 spotting of the kidneys is one of the most positive postmortem signc 

 of cholera. Acute nephritis is also seen with great frequency in 

 other acute diseases, such as pneumonia, pleurisy, and severe in- 

 flammation of the bowels. 



Symptoms. — In the cases that are due to hog-cholera and the 

 other acute infectious diseases there are no distinct symptoms of 

 the kidney inflammation, and this part of the trouble is usually 

 entirely masked by the symptoms of the primary disease. 



In a primary nephritis, coming on as the result of an injury or 

 exposure to cold and wet, the symptoms at first are not very severe. 

 The animal becomes somewhat dull, loses appetite and desire to 

 move about, and will lie in the nest most of the time. When forced 

 to move about the gait is slow and of a pecuhar straddling nature. 

 The evidences of pain in the back may be very noticeable, and the 

 animal may be unable to bear weight on the hind limbs. The sick 

 hog will usually stand with the hind feet well up under the body, 

 the back arched, and the flanks drawn up. 



The amount of urine passed is quite small, and is passed at 

 frequent intervals. The color of the urine is much darker than 

 normal, and in severe cases is of a smoky or even blood-red color. 

 The more severe the inflammation, the more marked are the changes 



