TENTH ANNUAL YEAR BOOK— PART VH 285 



sis ill a dairy herd may serve to contaminate a number of farms that 

 were previously free from disease, and to spread tuberculosis among the 

 hogs and calves of the vicinity. This particular means of spreading tuoer- 

 culosis could be absolutely prevented if all creameries could be induced to 

 sterilize their separated milk before returning it to the producers. 



The second cause to which we have referred is closely related to the 

 first, but may be more easily controlled. It is a cause which usually affects 

 but a single farm at a time, and does not damage any of the neighboring 

 stock, as it simply consists of feeding to the young stock on any farm 

 the raw whole milk from one or more tuberculous cows that may chance 

 to be members of the dairy herd upon that particular dairy farm. 



The serious results of feeding milk from tuberculous cows will be ap- 

 preciated when you learn that 83 per cent of a test lot of hogs that were 

 fed on tuberculous milk for three days only, contracted tuberculosis from 

 this brief contact with contaminated material. Other hogs that were fed 

 for 30 days upon tuberculous milk contracted tuberculosis without excep- 

 tion. 



The third cause of tuberculosis in hogs, feeding behind tuberculous 

 cattle, is far more important than is generally conceded. The discovery 

 was only recently made that many of the cattle that are affected with 

 tuberculosis, yet without shov\ ing any outward signs of the disease, have 

 their diseased areas so located that any discharge of tubercle bacilli must 

 pass into the alimentary tract, and thoy are thence evacuated with the 

 feces. It is impossible for a lot of hogs to run with a herd of cows of 

 this description without coming into dangerous contact with infectious 

 material from their feces. 



Feeding upon tuberculous carcasses is a fourth important source for 

 the development of tuberculosis among hogs. Occasionally a farmer's cow 

 will waste away and die, and the owner in an endeavor to save as much 

 of her value as possible, removes the hide and allows his hogs to devour 

 the remainder of the carcass. In case the loss of the cow was due to 

 tuberculosis, no more certain method of conveying this disease to these 

 hogs could be found. 



The fact has been well established that nogs may contrart tuberculosis 

 through eating the sputum of consumptives, and that whenever this oc- 

 curs, the form which the disease assumes is fully as severe as though it 

 had been derived from some bovine source. Proper precautions in select- 

 ing caretakers for farm animals will prevent infections from this source. 



Tuberculosis may be transmitted from hog to hog, especially from a 

 tuberculous brood sow to her pigs, but this manner of infection is so very 

 infrequent compared with the number of cases of bovine origin that we 

 do not need at this t'me to give it any very lengthy fonsideration. 



The Bureau of Animal Industry has recently been investigating a case 

 in which a large proportion of the hogs shipped from a certain ranch 

 were found to be tuberculous when examined at the packing house, while 

 at the same time it was learned that practically the whole poultry popu- 

 lation of the farm had the disease to a serious degree. 



It was learned that it had been the custom at this place to throw all 

 the dead hens over into the hog yard where they were greedily eaten. Ob- 

 taining a .pair of tubrculous hens from this affected farm, and a pair of 



