efi- 



Issued May 1927; Revised March 1935 

 Slightly revised December 1946 



?Ae PREVENTION sT 

 ROUNDWORMS « PIGS 



BHRANSOM (l) CHIEF, ZOOLOGICAL DIVISION 

 BUREAU OF ANIMAL INDUSTRY 



Tffii jgur 



LEAFLET W'fF «FTJ* NUMBER 5 



UNITED STATES DEPARTMENT OF AGRICULTURE 



CONTENTS 



Page 



Damage done by worms . 1 



Sources of infection 2 



Development of a system for prevent- 

 ing infection 3 



The swine-sanitation system 4 



Page 



Permanent hog lots dangerous 7 



Skim-milk diet supplements sanitation. 7 



Benefits from the system 7 



Summary of the swine - sanitation 

 system 8 



Damage Done by Worms 



The common intestinal roundworm or ascarid 2 is one of the most 

 injurious of the various kinds of parasites that infest the pig. It 

 causes digestive troubles, retards growth and development, and in 

 other ways interferes with the well-being of pigs, especially the 

 younger animals. Furthermore, scientific investigations have shown 

 that this parasite can cause a great deal of damage otherwise than 

 merely as an intestinal parasite. In its early stages of development 

 in the pig, and while still too small to be seen by the naked eye, the 

 worm travels in the blood stream from the intestine to the lungs and 

 then back to the intestine by way of the windpipe and esophagus. 

 This curious journey (fig. 1) requires about 10 days for its comple- 

 tion, after which the young worm settles down in the intestine and 

 grows to maturity in about 2% months. If many of the young 

 worms take this trip at the same time, as often happens, the injury 

 that results is liable to be serious. 



When the lungs of a young pig are thus invaded by numerous 

 young worms, the pig often shows symptoms commonly known as 

 thumps, and may die of pneumonia. Probably most of the cases 

 of thumps in little pigs are caused by worm infection, though the 

 characteristic thumping cough in young pigs has sometimes been 

 attributed by some hogmen to an overfat condition, or cold weather 

 with resulting lack of exercise. Pigs that survive a severe invasion 

 of the lungs by the young worms frequently do not recover fully 

 and fail to grow and develop at a normal rate. Bacterial compli- 



1 Died Sept. 17, 1925. This is a revision by M. C. Hall and H. B. Raffensperger of a 

 mimeographed article by Doctor Ransom issued by the Bureau of Animal Industry July 1, 

 1921. The revision incorporates some minor additions which are regarded as desirable in 

 the light of later developments. 



2 Asoaris litoribriooides or Asoaris suwm. 



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