DISEASES OF SWINE 481 



through the milk-secreting structures of tuberculous cows with 

 healthy udders, and hence no tuberculous animals should be al- 

 lowed to remain among dairy cattle or in dairy herds. 



The feces of tuberculous cattle are a menace to hogs even 

 when not deliberately fed to them. Very few establishments that 

 keep both hogs and cattle make provisions effectually to prevent 

 the access of the former to the manure heap on which the drop- 

 pings of the latter are thrown. No farmer or stockman intention- 

 ally practices a system of feeding that is lacking in economy, and 

 to know the benefits that are derived by hogs from the manure 

 heap of stables containing heavily grain-fed dairy or beef cattle 

 immediately causes its location in the hog yard. This practice is 

 not harmful when the cattle are healthy; but when they are af- 

 fected with tuberculosis it means, in the light of evidence we now 

 have, an almost certain transference of the disease to the hogs. 

 (B. A. I. B. 88.) 



Only recently a probable instance of infection of hogs by 

 cattle feces came under observation. Of 34 hogs which were mar- 

 keted in one lot 23 were found diseased, and upon investigation 

 it was ascertained that the owner had a herd of dairy cows, the 

 stable manure from which was thrown into the hog yard. The 

 hogs were given no milk, nor were they permitted to mingle with 

 the cattle, but were pastured and fed on corn and what they could 

 gather from the cow manure. In fact, the latter form of exposure 

 was the only plausible explanation of infection, and this was later 

 accepted when the tuberculin test of the herd revealed 19 out of 

 the 27 cows diseased, which test was confirmed when the cattle 

 were slaughtered and found to be tuberculous, some in an advanced 

 stage. (B. A. I. Cir. 144.) 



Pigs confined in small dry yards are no more susceptible to 

 tubercle bacilli taken in the food than are pigs on pasture, while 

 at the same time they are fully as resistant as are pasture fed pigs 

 to tubercle bacilli from other sources. In tuberculous swine, tu- 

 bercle bacilli of the typus bovinus are almost without exception 

 the only ones found in the disease centers. Tuberculosis of swine 

 has its principal origin in the tuberculosis of cattle and in the sec- 

 ond place in the transference of tuberculosis from one hog to an- 

 other. Nor is it impossible for the tuberculosis of other domestic 

 mammals and of fowls to be transferred to swine. The tubercu- 

 lous human being can give tuberculosis to swine, no matter what 

 be the origin of his own disease. As a source of infection, the excre- 

 tions and the flesh of diseased mammals in which living tubercle 

 bacilli are contained come chiefly under consideration. The great- 

 est danger comes from feeding swine with the separator refuse 

 from the dairies. The tuberculosis of the other domestic mammals 

 is to be traced back in most cases to the tuberculosis of cattle. It 

 is to be expected that the repression of the tuberculosis of cattle 

 will lead to a decrease of the tuberculosis of swine and the other 

 domestic mammals. (Iowa B. 92.) 



