682 DISEASES OF SWINE 



cold weather may produce abortion. In like manner, sows that 

 are allowed to burrow around straw-stacks and manure piles may 

 abort as a result of overheating. Overheating may also occur as 

 a result of excessive exercise, as by being chased about the feed lot 

 by boys, by strange hogs, by dogs, or by sows that are in heat. 

 Sows that are in heat are especially liable to cause abortion in preg- 

 nant sows through chasing them, riding them, and also by causing 

 a great amount of nervous sexual excitement. 



Abortion may occur as a result of straining, as from chronic 

 constipation, or by a slip on the ice. Falls received as a result of 

 slipping on the ice account in great measure for the large number of 

 cases of abortion during the winter season. 



Rough handling is another very common cause for the sow 

 aborting. This may occur in ringing, loading in wagons, or while 

 handling the animals for the purpose of injecting with hog-cholera 

 serum. When using serum in pregnant sows they should be han- 

 dled by means of a rope slipped into the mouth, and the serum in- 

 jected in the loose tissue back of the ears. 



In connection with the use of serum and its relation to abortion 

 it might be well to again consider the danger of producing abortion 

 from use of hog-cholera serum. In the experience of the author no 

 case of abortion has been seen following the use of the serum that 

 could be directly charged to this cause. Cases will occur now and 

 then from careless handling, but there is very little doubt that the 

 serum itself is harmless as far as producing abortion is concerned. 



Ergot and some other poisonous fungi and molds are capable 

 of producing abortion. Especially is this the case with ergot, and 

 where animals are allowed to pasture upon rye stubble fields abor- 

 tion from eating of ergot-bearing straw may occur. Food poisoning, 

 as from brine, washing powders, and similar substances, may result 

 in irritation of the womb and thus cause abortion. 



Abortion is also a common occurrence in the course of the 

 various acute infectious diseases. Especially is this true with hog- 

 cholera, and practically every pregnant sow that takes the disease 

 will slip her pigs unless she herself dies of the disease, and even 

 then she will frequently abort a few days before death takes place. 



Infectious Abortion. — This form of abortion results from the 

 infection of the genital passages by some specific germ, the true 



