316 Missouri Agricultural Report. 



factory that his faith has been somewhat shaken in the work 

 and teachings of the veterinary scientists. 



Taking the country over, we have no accurate data as to the 

 percentage of sows whose fertility is seriously affected by cholera 

 contracted from natural exposure, nor the percentage that 

 become sterile, or have their fertility affected from the "inocu- 

 lation disease" caused by the injection of hog cholera blood 

 when the "simultaneous method" is used. But that this is a 

 factor that must be considered by the breeder of valuable pedi- 

 greed sows cannot be questioned. Our correspondence with 

 farmers and the reports of the men we have sent out to investi- 

 gate cholera in various parts of the State show that cholera when 

 contracted from natural exposure, and cholera virus, when in- 

 jected with a hypodermic syringe, do cause abortion and affect 

 the breeding powers of sows in numbers of cases. It is my 

 opinion that no breeder will fmd it permanently profitable to 

 "advertise" that he maintains an immune herd by the applica- 

 tion of the "simultaneous method" of vaccination. This simply 

 advertises the fact that he maintains a cholera-infected farm 

 which in the end will drive customers away rather than attract 

 them. The disadvantages of attempting to maintain a per- 

 manent immunity of a registered breeding herd by means of the 

 "simultaneous" or "cholera blood" method so overbalance the 

 advantages that good breeders who now follow the practice will 

 discontinue it and others who are wise will not adopt it. Simpler 

 and harmless measures, of which I shall speak, will secure better 

 permanent results. The best advertisement that any breeder 

 can have is to show that his hogs that are offered for sale are 

 vigorous, in perfect health and have never had any disease, and 

 have never been injected with virulent hog cholera blood; more- 

 over, that the farm of the breeder is not infected with cholera 

 germs, but is kept in a sanitary condition. 



A breeding experiment which we made with a lot of 23 

 hyperimmune sows that had been used in our serum work may 

 interest you; these were a mixed lot of sows bought from farmers 

 in the neighborhood and represented the average in quality of 

 the unregistered breeding stock of the country. These sows 

 varied in weight from 250 to 400 pounds. They had been in- 

 jected a number of times with virulent hog cholera blood, in 

 the course of their treatment in preparing them for serum-pro- 

 duction, and were therefore thoroughly resistant to hog cholera. 

 Their breeding record, however, was nothing to be proud of. 



