74 NON-SPECIFIC OR GENERAL DISEASES 



In this country, Keer, Good, Giltner and others have proven 

 that the Bang hacillus of abortion is infectious for other species 

 of animals, and outbreaks of this disease have been said to occur 

 among breeding ewes pastured and fed on infected premises. 

 Its infectiousness for the females of otlier species has never 

 been proven in natural outbreaks. 



The disease-producing germs are present in the body of the 

 foetus, the fetal membranes, the discharge from the maternal 

 passages, the ficces and milk of aborting animals. The male 

 may carry tlie infection in the sheath, urethra and on the penis. 

 The natural avenues of infection are the maternal passages and 

 digestive tract. 



It is very seldom that abortion is carried from one herd 

 to another by means other than through the breeding of ani- 

 mals free from abortion to animals affected by this disease. 

 The purchase of a hull or coiv from an infected herd and breed- 

 ing them to animals that are free from disease, is a common 

 method of spreading the disease. After serving the diseased 

 animal, the male may carry the bacillus of abortion into the 

 maternal passages of the next cow he serves. There are numer- 

 ous cases on record where the bull was a permanent carrier of 

 the Bacillus ahorlus and infected nearly every anifnal served. 

 The distribution of the disease in the herd following the intro- 

 duction of a cow, sow, or ewe that has aborted before or after 

 being purchased, takes place through contact of the other ani- 

 mals with the virus that may be present on the floor, or in the 

 manure, or by taking the virus into the digestive tract along 

 with the feed and drinking water. Experimental evidence indi- 

 cates the latter avenue of infection. 



The stallion is the most common source of infectious abor- 

 tion in mares. An infected stallion may distribute the disease 

 to a large percentage of the mares that he serves. For this 

 reason nearly all of the marcs in a certain localit^y may abort. 



In case the infection occurs at the time of service, the abor- 



